What’s That Noise in My Differential?

This video chronicles what I went through to diagnose a whining noise coming from the 10 bolt (8.5” 30 spline) differential of my 1990 C1500 truck (GMT400/OBS). The noise has been there ever since I installed a new carrier and gears last year.
I cover checking backlash, measuring pinion depth, bearing inspection, gear tooth patterns, and fluid inspection.
I hope you find this information useful!
#ETCGVideo #ETCGDadsTruck
My Patreon Account: / ericthecarguy
The best place for answers to your automotive questions: www.ericthecarg...
Check out the ETCG Blog for the latest info: www.ericthecar...
Check out my ETCG1 channel: www.youtube.co...
Thanks for watching!
Links
Summit Racing: www.summitraci...
More info on noise diagnosis: www.ericthecar...
Diagnosing Ring and Pinion Issues: www.onallcylin...
Tools
Pinion Depth Measuring Tool: www.raceplumbi...
Dial Indicator Set (Checking Backlash): www.jbtoolsale...
Bleepin Jeep Pinion Tool: store.bleepinj...
Astro Pneumatic Bushing/Seal Driver Kit: www.jbtoolsale...
Milwaukee 1/2” (the big one): milwaukeetool....
1/2” Breaker Bar: www.jbtoolsale...
Torque Wrench: www.rakuten.com...
Part Links
My Differential: www.summitraci...
My 3:73 Gear Set (Original): www.summitraci...
New Gear Set (Richmond): www.summitraci...
My Differential Cover: www.summitraci...
Ratech Ring and Pinion Installation Kit: www.summitraci...
Pinion Bearing Set: www.randysworl...
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**Answers to your automotive questions found here: www.ericthecarg...
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ETCG
Due to factors beyond the control of EricTheCarGuy, it cannot guarantee against unauthorized modifications of this information, or improper use of this information. EricTheCarGuy assumes no liability for property damage or injury incurred as a result of any of the information contained in this video. EricTheCarGuy recommends safe practices when working with power tools, automotive lifts, lifting tools, jack stands, electrical equipment, blunt instruments, chemicals, lubricants, or any other tools or equipment seen or implied in this video. Due to factors beyond the control of EricTheCarGuy, no information contained in this video shall create any express or implied warranty or guarantee of any particular result. Any injury, damage or loss that may result from improper use of these tools, equipment, or the information contained in this video is the sole responsibility of the user and not EricTheCarGuy®.

[@labradormcgraw]

There's always a certain 'family' feel to ETCG's videos. The familiarity of his style makes us feel as though we're coming home to an old friend - a rare gift indeed. That's all before you get into the tuition, which is still - by a clear country mile - the best on KZbin. Long live ETCG!

[@ericthecarguy]

Thank you!

[@BillyRamirez]

It feels like we’re hanging out at his shop

[@tonyburts7998]

@@ericthecarguy where are you finding that pinion bearing preload should be 20-25 in lbs. All I’m finding is that it should be 14-17lbs. I’m chasing the same problem you had in my 05 Silverado. I think that I’m going to contact my gear distributor and see what they say.

[@wshazbot62]

@@tonyburts7998 this sound is the same thing my 09 Silverado is making. Makes me wonder if the shop I’m waiting for an appointment to take it too, is going to figure out the problem. Odd things always happens to me 😔, just hope it doesn’t cost me a fortune. I’m a disabled mom 58 yrs old, but was married to a mechanic for many years. So I always look for help, he’s now passed away. So I have no help, why I’m here

[@redwaller1]

@@tonyburts7998 I read in my manual for my Ford that the target preload should change depending on if you're trying to re-use bearings and crush sleeves. lower values for re-use.

[@jwstanley2645]

I am so glad to see that even someone who knows as much as you, and with all your tools and experience, gets frustrated from time to time trying to figure it out. So, here's to you!

[@ericthecarguy]

Anyone who says they don't is likely stretching the truth.

[@Salmon_Rush_Die]

Why are you glad someone is getting frustrated? lol misery loves company. I always end up doing everything three times to get it right, & then I realize I did the wrong thing after all.

[@myvideotablemyvideotable528]

After finding everything ok with my transfer case. i was going to open up the rear diff for diagnosing the shuddering in my 4wd. Well, after seeing this video, i guess i d rather leave it alone.

[@jwstanley2645]

@@Salmon_Rush_Die Knowing that even Eric gets frustrated helps me feel one tiny bit less stupid, after I stop cursing.

[@tona6g72]

Eric, I've been watching you for over a decade now. I am absolutely blown away with patient you are. You have a gift my friend. Wow! We can all learn from you in so many ways other than just auto mechanics.

[@ericthecarguy]

Meh, it's all in the editing. Thanks for watching!

[@billmillican3747]

I can't begin to tell you how much I've struggled with the same thing. Especially with pinion depth, damaging the inner bearing while taking it off to re-shim. I appreciate your videos.

[@dreednlb]

Yep, I just went through this. I paid an "expert" to install a new to me used diff in my diff housing so he could check backlash, etc. It was noisy. Then I took it back to him a second time and he said it wasn't my diff making the noise, it was the transmission. I paid to have my transmission replaced with another (used) transmission. It still made noise. I spent quite a bit of time researching the issues myself, purchased all new bearing for the diff and assembled it all myself this time. It's quiet now!

[@mubashircheentavida]

Ugh pretty sure I'm in the same situation, guy told me it was the trans but I'm like 90% sure it isn't but at the time I didn't know.

[@garychandler4296]

A mechanics stethoscope can save you a lotta money plus warn you of upcoming failures!

[@harvestblades]

How was the bearing replacement? Setting backlash has always kept me from messing with my ring & pinion on my Jeeps, but I don't have nor do I want to spend $1k on a shop replacing this.

[@dreednlb]

@@harvestblades bearing replacement was fairly easy. For the backlash, I pulled the diff myself and just handed it to a transmission shop to do the backlash, then I reassembled.

[@rayhat5111]

This is one of the best vids I’ve seen on auto repair. You’re skills and tool set are beyond the average home mechanic. This is no shade tree project. I understood everything you described so accurately, and have been at the end of a job to find out that wasn’t the fix. I would have lived with the noise after the first tear down. Outstanding job. I’m a subscriber now. Thank you.

[@AndrewBrowner]

the fix was right in front of you the entire time.. more volume on that radio!!

[@louiswhetsell1144]

Lol

[@AndrewBrowner]

@@louiswhetsell1144 thanks for your input.....

[@hunterlogan2913]

until one day... and with luck the wrong day...

[@arielbonilla1623]

Bro wth 🤣

[@michaelcrider8413]

🤘

[@pv2smurf]

That moment when you want to walk away and you realize...."this thing ain't going to beat me that easy". Then you take a moment and decide "it's getting fixed, regardless if "it" knows that or not. Love this setup of videos. Strongly encourage more like this!

[@ericthecarguy]

Thank you! Glad you like them.

[@cheesemons]

Great to know you figured out the problem. That's one less thing on your mind to worry about and that's one more things that we learn! Thanks for your effort.

[@tomcardale5596]

I've had a very similar issue with my rear diff after swapping it out for an ATB one. It's loud at 70mph driving along a flat road, quiet when accelerating, decelerating or going up a hill. If it's under heavy load it's quiet. This video has confirmed my suspicion that I'm likely to leave it alone!

[@DDescalchuk57]

From my experience majority of acceleration and deceleration noise is ring and pinion. Usually on worn out gear sets or improperly installed gear sets. Couple thou. Makes all the difference sometimes. Bearing noise is usually constant.. if you ever hear a mechanic say they don’t ever make mistakes they’re full of shit. We all do, great video

[@darrellhughes6773]

My 96 SS Impala is making d same noise think it's d same problem he's having??

[@frankpaya690]

Maybe the mechanic didn't make a mistake but his parents did?

[@williamtoon6021]

I was curious about the torque spec not being right. It wasnt just a little òff, it was quite a bit under. Jus' sayin...

[@mikebaz7843]

I ruined a pinion bearing after a clutch dump as it was only noisy on acceleration, replaced it and it's still silent years later. Carrier bearings will give you constant rumbling though

[@kalstonii]

@@mikebaz7843replaced what exactly? Im having noise between 20-50mph, and as i slow down

[@johnfink5060]

I have been watching Eric's videos for a number of years. I enjoy his videos because he is thorough, careful, and offers good advice. The way he shoots his videos and talks is very good. Kind of a comforting way of speaking is what he does. I used to be an auto mechanic from the tail end of the 70s and through the 80s and 90s before I hung it up. Eric has good methods on how he does his repairs. He is a good mechanic. He has been very helpful during the years when I used fix my kids cars. Oh the things kids can do to their cars! Good job Eric.

[@the_cheese]

From my training working in a bearing shop, it is a bad idea to replace a cone but not the cups in a tapered roller bearing. The races can have microscopic pits or grooves that will cause the rollers to hammer and degrade the bearing at a significantly faster rate than a new cup and cone. Glad you got that sorted out, Eric!!

[@carsandcoffee4546]

Here a little tip for ya, when you're doing axel bearings, don't soak them in gear oil and install them. I probably sound nuts, but use assembly lube. Reason being is because, if you soak them in gear oil, nine times out of ten by the time you get it back together. All the gear oil is gonna be ran off and when you go to drive it you're gonna be running the bearings dry. I've burnt up I don't even know how many bearings like that because of that reason. I started using assembly lube and I haven't had a issue since.

[@V28KINSA]

I hope this video was helpful? God bless you Eric! You really solve much doubt about differential...

[@shadetreeautomotiveenthusi1284]

My Dana 60 calls for 250 on the pinion nut. I had the same experience 10 years ago with Richmond gears, on a semi-floating Dana 60. Seeing those pinion bearings cut leaves me with the impression that the torque specs were off, and it break in the ring and pinion to a whine/houl. By the time you replaced the bearings again, it already existed. Replacing the bearings was necessary, but double check that torque spec. And my videos aren't monetized, so when I say Chinese mil spec is junk, that's exactly what I mean. Japan, Germany, or old stock U.S.A. is all we can hope for, for good mil spec bearing race kits. Good video, guy!

[@80sfordguy]

Great video Eric, though no matter what gear lube you use, even with perfect gear tooth pattern, pinion bearing preload, carrier bearing preload and gear backlash there will always be a slight gear wine on deceleration. It’s normal...... Now that your differential is broken in, readjust your backlash to within the Factory or Gear Manufacturers 0.005” - 0.009” spec and try getting it within the preferred spec which is likely 0.006” - 0.008”. Personally, anything gear backlash between the tight 0.005” and midway point of 0.007” on a GM 10 bolt is good and you’ll still have slight gear wine on deceleration!!! Run it for 500 miles then change your gear lube to remove any wear deposits and go from there with fresh quality 80W-90 or 85W-140 (viscosity is dependent on the temperatures you drive in) synthetic gear lube with LSD additive (4oz is common) if you have a Limited-Slip Differential. I think Eric has just proven that you never mismatch new bearings with old bearing races is not a good idea. Plus, if your gear teeth have any chips, it may cause noise even if everything setup correctly. Also all differentials have a lube oil change interval like other oil change intervals your vehicle needs as maintenance.

[@jeffkelley3419]

I agree. He should run his truck for a few hundred miles, drain the old oil, and readjust tolerances. It's sad that he will have to drain the synthetic oil. However, he'll be happier in the long run. Sorry, Eric. Easy one for you.

[@frankpaya690]

@@jeffkelley3419 You really think it was necessary like he did, when he was trying to figure out what was wrong, to dump the new oil when it was brand new and in a broken in assembly and all he did was test drive it?

[@williamtoon6021]

Both of the gears had chips in them. Spinning at thousands of rpm, out of balance parts are likely to "sing". Thats what ive been taught.

[@SSCREAM100]

Had the same noise in me colorado. Though after some digging, seeing this video and remembering repairs I've done to the pinion seal, I have come to the conclusion of water damage to either the gears or pinion bearings as water had been getting into my diff via the diff breather and blowing out the seal. I hope it's just the bearing anyway. I learned more in the video than I have in weeks researching shit I dont understand because of all the bullshit everyone else talks about to sound smart. Cheers mate

[@ThatKZ900LTD]

Did replacing the bearings and seals solve the problem? I just did all my bearings and seals and I still have this noise the wear pattern is fine and I’m not sure if it’s gears ( backlash and depth being wrong ) or if it’s just noisy from factory

[@SSCREAM100]

@@ThatKZ900LTD it did. My pinion bearings was rooted. Haven't had am issue since now.

[@chriskystoneadventures]

If your carrier dropped out it probably was not preloaded properly resulting in too much pinion backlash under load which would cause noisy gears. Those two big holes on each side of housing are for a carrier spread tool to remove carrier assembly. You spread the housing with your dial indicator very carefully to not over spread. This is what preloades this style of diff. Use a long bar after carrier is installed to pry on carrier with dial gauge set to get zero end play and then add proper amount of side shims to get carrier side bearings preloaded.

[@geoffreyplagnieux7517]

Hi Eric, I'm from France and I have exactly the same problem on my 1998 Chevy Tahoe. Your video was very helpful and permits to me to gain a lot of time. Nearby 2 years ago I've rebuilt my rear diff I've changed all the bearings, my mesures were very accurate, and my pattern was very nice. But since 6 monthes I've the same noise on my rear end. As you, I Thought that is was comming from pinion bearings, and it has to be my first step to check where does it comes from, I thougt too that it could came from the gears themselves... and that is it! Thanks for all!

[@richu27]

Eric: I am closing this chapter for now. Also Eric: *with disassembled differential* this is where I am now.😂

[@ericthecarguy]

Take a break, get some food, get some rest, and start fresh tomorrow. Good luck!

[@frankpaya690]

@@ericthecarguy How about go around the shop and pick- up the tools and parts ?

[@CalloftheCrow]

Great video man. I respect a man that can reveal hurdles of troubleshooting and not be prideful.

[@Rook101]

Wish I had this video as an introduction when I tried my first dif rebuild. Well done Eric.

[@arth.4196]

I have been watching you for so long I learned a lot. A craftsman like you just shows how easy it is to do what you do. If a person really wants to learn a Trade. I have learned a lot. I took an ASE test and passed it for Brake and Suspension Certification. Keep on doing what you do. Thanks

[@ericthecarguy]

Thank you, and congratulations on passing your ASE test!

[@Mo-sf7wc]

Hey Eric, I appreciate how open you are and with your experience that you are not afraid to be honest when having an issue or troubles. Something I wasn't sure if you checked but I had this exact same issue with a Silverado. Done plenty of rear ends before never had an issue however one Silverado I did kicked my butt. I had that thing out a million times it felt like. Long story short my preload on the carrier was the issue. I think that may have been your issue too because you mentioned you ended up using the factory shims in the Richmond set up. Long story short I did what you originally did and measured my old preload and stacked shims to obtain the same. Turns out a little bit of fluid/dust between the shims gave me a false reading of more preload. What I ended up doing was cleaning the shims in acetone and measured then separately. I wrote down the measurements and played them out. Than I added off of those figures vs stacking and than seeing how thick they were. I did it each time I took it down until I got the right combo to get the gear lash I wanted. That solves my issue. My theory is my preload was a little loose and that ultimately would cause the ring gear to move away from the pinion on decel which caused the exact same noise. I've never had to go to that detail/trouble before with any other build since. Makes me think the Chevy 8.5/8.6 are just sensitive. I could be wrong but that's my theory. Anyways how is your dad's truck doing? Been a while since we've seen an update on that.

[@JeremyDN]

I know this is very old but I have this exact problem right now. I have a lot more faith in doing this myself and actually fixing the problem and not just throwing money at a mechanic. Very much appreciate this video and all of your videos.

[@krawlr]

I use the Yukon "super carrier shim kit" and "crush sleeve eliminator" whenever I can on gear installs. You can dial that backlash in where you want. (yes I prefer the tight end of the spec) And no more finger crossing while setting pinion preload.

[@jcnlala9461]

I have a Ram 1500 and it has this same noise. It just started noticing it. I'm glad I came across this video.

[@jockosboy17]

I had the same issue after going from 3.08 to 3.73 with the same diff but in a Tahoe. It was ultimately better after replacing all the bearings a couple times and setting it all to spec but never solved. I traded it off...

[@jeffkelley3419]

Sorry to hear it. I hope you have a better truck, now.

[@jockosboy17]

@Nick J What was I suppose to do with it?... Keep it forever? NO. I traded it to a GM dealer who has the capability to correctly solve the issue.

[@kevbush]

Many a year ago I worked for Ford in their powertrain NVH group and axle whine was a inexact science even on new axles. Visteon (our axle supplier) had an expensive machine called a veritach that would measure the transmissibility error (TE), which is the rotational discrepancy between the pinion and carrier. Even that machine wasn't perfect at predicting axle whine. Axle whine can be a system problem, meaning that the engagement can set off a natural frequency in the axle. Everything from component materials to weight to suspension bushings can affect its severity and manifestation. We used everything from torsional dampers in the driveshafts to "moose balls", which was a tuned damper bolted to the rear end, to improve the noise. Glad you got it fixed; great video 👍

[@ericthecarguy]

Fascinating. Thanks for that info.

[@billyleedee]

I’m on your side about prior setups. Seemed reasonable. Two years ago I rebuilt my diff with the identical Richmond set, and it’s behaved well. Hope the same with yours..

[@thhall459]

I will never disassemble or work on a differential. Having said that, I couldn’t wait to watch you do it and I couldn’t stop until I saw it all the way through to the end! I like what one of the other commentators said about you having a familiar family friend charm! That’s a very apt description of your style.

[@ericthecarguy]

Thank you!

[@jeremymoran5123]

Eric, I think your problem might be in the excessive backlash. Every time I built a rear end I’d always shoot to get the backlash within the manufacture specs.. Typically if you could hit the within the specs. you were on the money. Great video as always, thank you sir from Oklahoma 🤠

[@shellyshell311]

Thanks for this video. I have the same noise with my Mustang as I hear in the beginning of this video, and the same issue of it increasing with deceleration. Was contemplating doing it myself until I watched all the tools and knowledge required. Am so proud of you for your persistence and payoff, you're so inspiring and easy to learn from. I love your axle cam! 😄 Thanks for enlightening my evening and at the very least giving me the assurance, that, yes, that noise is in the differential.

[@bizzybcarm.d.7828]

Very informative as always! I've never been confident setting up rear and this is why haha

[@gc1362]

I just did my first set of ring and pinion gears in my 84 GMC Sierra classic 1500. It had 2.73 gears in it originally so that's what I put back in it. I bought a set from O'Reilly Auto Parts made by Motive Gear and installed new pinion bearings and races... I checked everything several times and all my specs were good... took it for a test drive and heard that exact same noise that's in your video. Immediately came home, put it back on jack stands and check everything again... put new fluid back in it and I still have the same noise... I really hope my noise is caused by the same thing.

[@BrewBlaster]

I didn't like how that old pinion gear looked at all. You just got a better quality gear set the second time around.

[@NoWr2Run]

YES, WAS NOT HIS MECHANICAL SKILLS IT WAS THE BAD PART.

[@jeffreymurdock8366]

Eric theres a trick i used on a noisy rear diff. Couple small tubes of graphite powder. It helped. The reason is it fills in any slight imperfections.

[@megaglowz8540]

The mechanics shanty. What’s That Noise in My Differential? What’s That Noise in My Differential? What’s That Noise in My Differential? Early in the morning!

[@hornetkeeperh]

Wife comes in, says I smell of oil Wife comes in, says I smell of oil Wife comes in, says I smell of oil, Early in the Mornin

[@kiellivingston7100]

@@hornetkeeperh Wife says come to bed, it's midnight, Wife says come to bed, it's midnight, Wife says come to bed, it's midnight, Early in the morning!

[@the_cheese]

Are you sure that clamp is tight Sure I'm sure that clamp is tight I'll swab that coolant up just right early in the morning!

[@jaimejay6056]

That's tenacity

[@PutteDanerhag]

Work for a truck manufacturer in Sweden and I assembled the differential and now I work as an operator manufacturing the pinions and gear. Point of contact is very important but what will make that sound is the chipped tooth without a doubt. When we test the gears in a sound machine just a small strand of hair at the edges can make it sound very bad. I figured it out though and installed new pinion and gear so everything was fine after that 👍🏻

[@PutteDanerhag]

* u figured

[@emasbury]

Eric, I have this annoying noise coming from my passenger seat of my 2015 Chevy Silverado, but I have found out that is goes away when I leave my wife at home. Can you help? :)

[@russlehman2070]

Well, if you absolutely can't convince your wife not to ride along, duct tape can work wonders. Disclaimer: I take no responsibility for what your wife does do you after you apply the duct tape.

[@Fuaarrkk]

Divorce

[@chevrolot06]

I try try ty

[@FortniteZombiekiller]

@@russlehman2070 duck tape fixes everything

[@DuckOff691]

Dont have this issue on mine. Made damn sure of that!

[@earache_srt8790]

I have the same noise in the rear of a Dodge truck. I had a mechanic disassemble and inspect it because I had plans for a motor swap. The noise was slightly different after it was reassembled with synthetic oil. It has about 6000 miles and still has not changed. The motor swap was completed about 4500 miles ago. It had a 4.7 and now sports a 6.4 Hemi. Sounds like I need a different gear set as well from your video. I had suspected the pinion bearings same as you. Anyway, well done sir.

[@Erik_Swiger]

"Well that was easy enough" said no car mechanic ever except ERICTHECARGUY

[@jeffkelley3419]

'bout right!

[@Steff320i]

The technical quality of yor videos has become so good. Excellent lighting, sound + editing. Thanks for sharing.

[@iaahner]

Good video and I love the content! As a guy who does a lot of diffs though, let me say this. 4 thou on the pinion depth is not something I would call "close enough" and move on. And the paint pattern you show at the end confirms. It's close, but I probably would have made a shim adjustment to get that closer. Same with backlash, 11 isn't really what I would call "close enough to 5-9" and leave alone. A few thousandths seems like a silly small amount to be bothered by, but in differential setup it really does make a difference. Regardless, glad to see you got the problem fixed!

[@dannybracken3499]

I appreciate all of his hard work and time spent , and shared his journey with us . Even though it was a little noisy , it probably would have been ok . I thought the same thing from the very beginning, ring gear end play excessive . In hindsight I guess that even if ya have to take your thicker shim to a machine shop and have it ground to get the clearance at the bottom of spec ,,, it's the right thing to do. If that was a High performance car , it would have scattered the gear ! Thanks Eric

[@jayfuller3709]

Hi, now I am Leery about changing my Diff. My truck is a one wheel diff. I purchased a Tru-Track diff for it. I have all the equip to do it, but this video makes me rethink what I am doing!!

[@ericthecarguy]

Just allow yourself plenty of time to work and be patient. If you can, track down one of those pinion depth gauges as it takes a lot of the guesswork out. That said, if you're only changing the differential, you really won't have to worry about the pinion at all. You just swap the ring gear onto your new diff. Good luck.

[@don_chuwish]

This gives me an idea for a collaborative series "Eric consults with Eric" on head scratchers. ETCG and South Main.

[@jayss10]

Didn’t get to the end but this is extremely common with certain manufacturers of gear sets. Richmond gears tend to whine ALOT due to how they are cut. Motive gears are much quieter.

[@Brownnproud91]

I always thought eric the car guy was eric from south main auto. Lmao

[@Smalltechguy]

I never tire of your videos. When I seen this Chevy getting some attention I just had to tune in. I've had my 1988 Cheyanne reworked with 4.56 gears in the back. I'm running 35 12.50 RL 15 tires. Since I didn't replace the front gears placing it in four wheel drive is useless. My issue is trying to find out the original gears that came in this model truck. I had written Monster Transmission since I had purchased a new transfer case from them, but I guess folks are still not getting back to work yet to answer my question.

[@AnonymousAlcoholic772]

Haha, just discovered this dude has his shop 7 miles from my house. Passed it the other day. Small world. Im in Reading lol

[@fatkat311]

Wow.. I never knew that. I live a few exits up from his shop just off 275. Never knew he was in Cincinnati

[@leonardcherry1314]

Lucky bass

[@jwbranham2009]

I appreciate your video and the honesty of your presentation. I like the detail and efforts to make sure we can see the important aspects. My grandfather would say to me there may not be enough time to do the job right the first time but always time to do the job over.

[@jonnymiskatonic]

"Differential fluid is one of my favorite smells" until you said "Not" I was just stunned. I mean putrid rotting skunk sprayed onions would probably be more pleasant than that stuff. Ick.

[@Jakek200]

Some GM AcDelco fluid smells like Grapes... Yes really, its scented. You can still pick up a little whiff of the normal gear oil smell under the grape smell though.

[@timwhite4288]

Need that smell to warn you the Pinon seal leaks and throws differential oil on the muffler!

[@hisagisan]

Your videos are awesome. Your out loud self talk is super valuable

[@rogerhinman5427]

"Okay Eric we'll send you a new set. Thanks, bye!...Hey Frank! You still got that pinion set that you dropped off the truck? I got someone who'll take it!"

[@jeffkelley3419]

Hil-larious!

[@ericthecarguy]

Funny, I had a similar thought but kept it to myself.

[@armoricain]

ROFLMAO!!!

[@Fir3Chi3f]

I appreciate you posting these videos where things haven't gone quite right. Thanks Eric!

[@MechanicMindset]

So clean under there!!👌

[@brianhind6149]

Eric: The suggestion to use synthetic oil I didn't agree with. The manufacturer used hypoid gear oil & it didn't make noise & doesn't in millions of differentials.. If synthetic oil had cured the noise, I would still be scratching my head when they buried me ! Great video, & as always, I learned something. Thanks Eric

[@grandmackdady]

wow you would go nuts with my diff. yours is quit compared to mine

[@hemp6956]

Thanks for the videos, brother. Even though most don't pertain to my vehicles, they're informative and enjoyable.

[@ericthecarguy]

Thank you for watching!

[@josh33025]

I had a rear end that sounded like you were banging on the frame with a hammer every rotation it made. I didn't take it apart to see what was wrong I just replaced it with a junkyard one.

[@bradrolling8637]

Im not a mechanic and i dont have an issue with my differential, BUT, i watched the whole thing, twice! lol Very good ,informative video. You sir were made for this . Thanks

[@aserta]

20:36 every lip on "inside" portion of those teeth is raised, as if someone had smashed it with a hammer (absurd comparison). Note how the cut marks travel up, so that wasn't a factory thing, this was something that was raised in use...could it be ...that there's an angle of contact issue here, like a defective case or defective ring gear seat? Because that would cause excessive noise. These gears are extremely finicky and demand very precise angles of contact both in the ring's plane and the pinion gear's. The way i see that gear, it's almost as if the contact was done only on the inside (towards the bearing), with rotation upsetting metal, raising those lips on each of the teeth. This would also explain the chips. You're essentially asking an elephant to walk on ballet shoes. You can clearly see the difference between the new and old gear.

[@ericthecarguy]

The old gear was like that out of the box, see the previous videos linked in the description. I wish I had smoothed out those chips before installation as that might have solved the problem from the get go. As for measurements, as you can see in the video I was pretty much bang on since the beginning with the exception of backlash. Note that the backlash was the same on both gear sets though. Still, I learned a great deal during this struggle and now I have a new tool that I can use on the next set of gears. So much of what I do is sharing my experiences with this stuff so that viewers know what to look for when they go to do this work. In a way, my experience is their experience. Some people see that as me not knowing what I'm doing, but in truth, I show my failings so that others don't have to suffer the same fate. Thanks for your comment.

[@jeffkelley3419]

@@ericthecarguy I still believe the new set was fabricated better. The teeth weren't so sharp. The old one looked like it was designed for a jet turbine, but that metal is probably titanium or something similar. I'm more comfortable with the new set. And, hey, it's not my truck. : \

[@OOpSjm]

@@jeffkelley3419 Night and Day difference in the manufacturing quality of those 2 sets.

[@MASS1866]

I have known guys to rely on the gear pattern past for ever. It’s how we were tough in college back in the day. I agree with those who have been saying your way of presenting and persisting in showing how to solve a particular problem is second to none. Thanks Eric.

[@NickNakorn]

Excellent video Eric. The take-away for me was whether or not it's worth tracking down and solving such a noise given the cost of finding it and curing it. Mostly I'd say not. I had a vehicle with a noisy diff that ran well with the noise (it did get louder over the years) for nearly 100,000 miles. Passengers would say 'what is that noise - do you have a bearing on the way out?' and I found that regular oil changes kept my mind happy even though I knew the diff was in need of work. Of course, if the vehicle was going to be raced or used to haul heavy loads I would have been anxious but otherwise; no. Nevertheless a great video albeit an expensive fix in terms of time and money.

[@ericthecarguy]

It really is about picking your battles isn't it?

[@NickNakorn]

@@ericthecarguy Yes, definitely! :-)

[@fabricancustoms]

My friend is having the same issue on his '90 Mercedes E300. I'm glad you are so thorough, because the diff rebuild video and this one will help him out a lot. Thanks, Eric

[@ericthecarguy]

If you can, find one of those pinion depth tools. Extremely helpful. Linked in the description.

[@sidwalker6902]

Pinion had summer teeth, made ol' girl talk with a lisp

[@1BarryMoore]

Thanks again and your attempts at objectively! New tools, new measurements, oil, parts, and installation, etc.

[@martij30]

My guess would be on the edges of the chipped pinion gear, that must make some local vibration resulting in the sound.

[@jeffkelley3419]

A case where maybe you shouldn't let the chips fall where they may. : o

[@frankburn6312]

They don’t touch the ring gear.

[@kevinteeter8098]

I talked to a very knowledgeable older drag racer when I built my 10 bolt and he told me to set the backlash on the tight side for street and loose for racing. My first install was with a motive gear set. Made bad noises. Switched to nitro gear with no more noise

[@andrewbutton5580]

Depends on stick/transbrake vs stalled auto and a bunch of other stuff. Depends on the intended usage. High shock load then 12 seconds of running needs different specs than highway heat building.. Gear composition as well setup. Just like an engine, horses for courses.

When you said differential fluid was your favorite smell i was thinking you were some maniac lol. Good thing it was a joke. That stuff is ronchy, and then when the diff goes out, ah man that swamp water smell is just torture.

[@eaglefeather]

Tell me, I changed my clutch in my FTW diesel and y trenny was bad so i bought a new (used) one from a car that have sat for almost 10 years. I got the trenny checked and it was just fine but the guy that I was checking the trenny with said that by the smell and color of the fluid it may only had 1 fluid change (in 23 years). BOY that smell was hard hitting.

[@jeffkelley3419]

@@eaglefeather Wha'dya expect from dead dinosaurs and manure?

[@eaglefeather]

@@jeffkelley3419 gas smells better xD

[@jimtekkit]

I reckon that Castrol Limited Slip 90 gear oil actually smells good. Other brands I've tried have been the total opposite. Real nasty like rotting mucus or something.

[@richardmitchell7836]

Perfect timing ,I was doing brakes on my 04 Super duty and while pulling the axles out I heard a Unfamiliar noise, pulled cover off and found chunks of teeth 👍. This video made my mind up to do it myself since I was on the fence about it. Thanks Eric! Don't forget that every tool is a hammer lol...always good content from your channel Thanks again

[@ericthecarguy]

If you can, I highly recommend tracking down one of those pinion depth tools. They can be very helpful. Also check out the rebuild videos linked in the description. Good luck and thanks for the comment.

[@richardmitchell7836]

@@ericthecarguy I have done a couple of rear ends but with a guy that's done it all his life and along with transmissions and he's retired now but he reached out to a buddy of his that will loan me that tool as well show me how to use it, weekend keeps looking better thanks for all you do for us! 🇺🇸

[@ericthecarguy]

Thank you! Sounds like you're in good hands. I'll be releasing the video about how to use that tool next week but it doesn't sound like you'll need it.

[@richardmitchell7836]

@@ericthecarguy I'm still going to watch it, never have enough knowledge...and I agree with the smell of gear lube...the worst. Btw the wife is happy since I adjusted the valves on her 2.3 hondoo..thanks to your video. I'll stay dirty lol

[@MendingThings]

I actually noticed in your first video series that you installed the carrier bearings flush with the stub, instead of tight against the shoulder. As when you pushed them on, you didn't use anything to push the bearings past flush. I would think this would potentially leave a few thousandsth of gap between the bearing and the shoulder that it is suppose to rest on. That would also explain why when you tried to use the same shims that was origninally in it, they were too tight. Just wondering if this had anything to do with it?

[@bunning63]

Mechanic told me of his days working as a tech for a Jaguar dealer in the seventies in New Zealand. They had a customer with a XJ12 they had bought new, and it had a rearend noise. They ordered in a new gear set and pulled the rearend apart for installation then realised there was an issue with the new set, if I recall the ringgear had the holes drilled but no threads cut, a problem after heat treatment. Since the customer needed the car for a trip that weekend, they reinstalled the old set with the expectation they would redo the job once they got some new parts. Customer contacts them the following week and told them the noise was gone. I asked if they reset the diff and they simpley reinstalled it as it came out.

[@CameronPinto]

Learned a bunch. Thank you!

[@willhikearizona]

At first I couldn't figure out what the noise or problem was, but then you finally got it sorted out, only then could I tell the difference in the noise.

[@yambo59]

deceleration is often to much tolerance / tooth pattern, im also thinking gearset mismatch. You likely got a badly machined gearset.

[@joshlentz6665]

What about acceleration only? I've seen that yal have mentioned deceleration in particular twice now

[@europeanlingerie1761]

mismatched used gearsets, almost always cause additional noise, it will go away as they run in another 100.000 miles or they can completely explode, al depends one ones luck

[@mnmz6934]

Hey man, great video! I've been puzzled issues with grinding, thumping, and clacking noise on my Jeep Wrangler JL for a year now. I highly suspect noise is caused by the diff, but the dealership is telling me its normal. These noises are driving me nuts, and only happens occasionally (mostly when its colder or wet). The vehicle would thump/clunk coming to a stop when it happens and if I put the vehicle in reverse, a clacking sound happens occasionally too (sounds like something is binding). I've been hearing a whirring noise when going around 45 mph and this noise can be manipulated by feathering the gas pedal. Dealer told me that some Danas are just louder than others. My tires were also cupping, which dealer blamed it on alignment. Lastly, there was oil residue on my diff and the dealer said it was the drain plug, which I find it hard to believe because oil residue can be seen all the way to the driveshaft area. I don't feel any vibrations or turning issues. So could this just be normal diff slack or is my vehicle's diff starting to go bad? Thank for your time

[@jaywilbur515]

Same dilemma with my significant other. Years have i tried to solve it. I came to the conclusion years ago there will always be a little whining ◑﹏◐

[@painterken2542]

Try given it a good wack with ball peen hammer..if the wineing continues use larger hammer and more force..it will stop

[@darthvincor]

So frustrating, all that work and then it's still making a whining noise. Good you fixed it in the end.

[@the2120company]

yep, I just been there in april, same "dancing with a wolf" noise auuuuuuuuuuuuuu :)

[@Redlinecarcare]

Great man,great display of patience and not giving up, you are blessed with a great gift and knowledge,and it is trait to share knowledge

[@ninjamaster3453]

Seems like that pinion gear all nicked and mating poorly to the ring gear. Would've lived with it on an old truck, doing this 3 times no way.

[@jeffkelley3419]

It may be that there is something more Eric's new and old subscribers could learn from this. I know I did. This seems like a straight-forward operation with the right tools and a little patience.

[@miketienhaara7783]

I heard a clunk sound today during a turn. Sounded like it was from driver side. Differential has fluid on outside. Whole thing needs attention I know. Your video is excellent. I like that you saw it through to the end Two thumbs up!!!

[@MrWilliam.Stewart]

Why did the alcoholic chase the car down the street? Because there was a wine in the diff.

[@chrisw3771]

Just watching this & the noise is exactly the same we used to have with some straight cut gears in the 70's -80's. It was the gear teeth bottoming out in the opposite gear. slightly relieving the tips of the gears & undercutting the oposite groove always worked. Utter pain to do though.

[@yourface8698]

Hey where's my digital cake it's my birthday 🎂😁

[@ericthecarguy]

I do that on my ETCG1 channel not here. kzbin.info Happy Birthday!

[@jayjanyh2932]

I had his channels mixed up too. His budget is bigger over on his ETCG1 channel, so that's where he can afford the cakes.

[@pizzamon795]

Happy birthday your face

[@markmckinley5989]

I have a 97 K1500. A couple of shops I asked about having rear end done claimed they would only use original GM gears since all the aftermarket ones they had tried would whine.

[@Retired70]

Patience is golden. Good job

[@GeertPolo]

8:20 Yes it is, my personal opinion. Lovely to see the truck, very nice build. Good quality content.

[@ericthecarguy]

Thank you!

[@dueyshaw3023]

Going thru a 2001 Silverado rear end right now. It is the open rear end and the smaller bevel gears both had most of the teeth breaking off the outer edge. Your video was a big help in what to look for and what to expect. Thanks

[@ASEWorldClassTech]

So if you look up about any Pinion bearing/race combos on Advance Auto, Autozone, Orielly's they always have Bearings & Races Separately. There are combos you can buy with the bearing & race in the same box. I always advise people when your rebuilding a diff. Always use either Koyo or Timken or OEM Bearings which are usually one of the first 2. That should be your first choice and don't cheap out. Buying Chinese bearings that aren't made as well as Japanese or USA made will always have you doing it all over again. Your backlash was 11 in the other video and will always get a tad bit higher after it breaks in. You seem like a great guy and your videos are always pretty entertaining and I appreciate the upload and the content. I did however look up BCA bearings and it says that 30% are made in Illinois which possibly means that the other 70% are China. I'm waiting on parts myself for a GM 8.0" rear on an LS swapped Canyon Race Truck. Eaton Detroit Truetrac is the LSD I chose. Most Pinion bearings are like $16.99-$25 for me. The Dealer Koyo Bearing that doesn't interchange well is $86 for the inner. The Outter is a Timken that's $56... It's insanity, but I wanted to keep the same bearings that are in the rear. I would rather pay twice the amount for a part than pay for the part twice or argue with the parts store about warranty. Wise words for the less experienced viewers of the channel. Take care bud...

[@dave_n8pu]

I especially enjoy these episodes with your dads truck because I also have a GMT400, BUT the body on his truck is SO much nicer than mine. If I remember it started out in Chicago as a delivery truck, salt on the roads...

[@davidlanghoff]

I admire your tenacity and technical skills. Always a learning experience watching your videos. Thank you very much.

[@sweenep86]

Eric, you need a lower range torque dial gauge and have to measure carrier bearing preload either by case spread or cumulative rotational torque of the pinion.

[@Roaddog77]

Really helpful. I have the 1999 LS 4X4 full size pickup and I have to diagnose the issue with my rear differential, however. I won't have to do any of the rear-end stuff this will be the pinion gear and ujoints. This video was very helpful. Thanks a lot..

[@SmittySmithsonite]

Nice work getting to the bottom of that one. Based on an experience I had 20 years ago, I would've sworn it was pinion nut torque that was the issue. I had an '86 Grand Marquis (exactly like the one I own now, only dark blue instead of light blue) that I changed the pinion seal on. After the job, on the test drive, I got an awful howl on decel. I ended up just having to turn the nut another 1/8th of a turn tighter, and the noise was 100% gone. Of course, this was with well worn-in ring and pinion gears - 230k miles at that time. I swapped the carrier in my '07 Silverado last year after a routine spill-and-fill turned up a bunch of metal stuck to the magnet inside. Closer inspection revealed that nearly all the teeth on my side gears were shed right off! 97k miles - they sure don't build stuff like they used to! I bought this truck spankin' new, and I haven't the slightest idea when this happened, or when it started - the diff was completely silent in all modes of operation, and never gave me a hint of any trouble. I installed an OX air locker, and set the preload pretty tight at .004" - the very bottom of the spec. I have a nearly imperceptible howl at light throttle settings that goes away upon the slightest loading in each direction, accel, or decel. Running Amsoil Severe Gear 75w-110, since I haul cars every so often. It's not something I'm going to chase, because I think it's due to moving the mating of the ring and pinion out of the already established wear pattern. Only a ring and pinion swap would cure it completely. Recently I had a '95 Volvo 940 wagon come in the shop with rear end shudder that would happen only when on the brakes, and just before a stop. On the lift, the whole housing would violently shake! I can't for the life of me figure out what is causing this! I pulled an axle - bearings and races look perfect. Had the cover off, and everything looks good there. All the support arms have good bushings in them, so there's no strange pinion angles happening. I would think if this were a bearing issue, we'd hear noise - it's silent, until just before the vehicle stops. The problem is exacerbated using the parking brake. Starting to wonder if maybe I have overlooked a bad rear u-joint? Differentials are amazing pieces of engineering! I would have never attempted my own install of that Ox Locker had I not seen your Fairmont and the truck vids. I just had to see someone else do it first, and that gave me the confidence to go for it. THANKS Eric!! 👍🍻 And you and the family have a great Independence Day.

[@HoldandModify]

As soon as I heard that noise I knew right away. Gears. Only because in the Mustang world we’ve been dealing with Motive brand gears always being whiney just like that on coast. Which is why I don’t buy Motive. Glad you got it sorted. Rear end wind bugs me like nails on a chalkboard.

[@indayceles6408]

Eric, i would have to think that the gear tolerance is a precise limit. Therefore, i would also think it is crucial to be in those tolerances. .002" out could be a big difference in certain industries and possibly there also. If the noise comes back, let us know. Also, i can't believe you, as a mechanic, would re-use the bearing races! We leaned not to do that in H.S. Auto Shop Class back in the 70's! (Back when high schools still offered it as an elective!) Other than that, love your videos! Thanks for posting! Nick.

[@ericthecarguy]

Both gear sets had a backlash of .011, so I'm not as inclined to agree with you that tolerance was an issue, but it could have been I suppose. As for reusing the bearing races, like I said in the video, they were the same brand and part #. Also, changing the bearings and races had no effect on the noise, so I don't think it's as big a deal as you mention, but it is the 'proper' practice. Thanks for your comment.

[@darelvanderhoof6176]

I did that with a rear wheel bearing on a front wheel drive Horizon, I reused the old outer race with the new bearing. The result was it kept loosening up for about a year due to accelerated wearing, then it settled down and was good for the rest of the car life. So I concurr, change the whole bearing and do not reuse the old race.

[@jaredcowan3180]

Great video! I’ve watched a lot of these and you did a much better job than most on this.

[@ddlago]

Yes you are correct , always install new races that come with the bearing and always put a new crush sleeve in never reuse it, i also look at the outside of the pinion races as the diff housing wears and the races will spin or move in the housing .