Making Quieter Oil Pump Gears for E55 / CLS55 AMG

Website: xfmotorsports.com/
Instagram: / xfmotorsports
E-mail: [e-mail]

[@Uninfluenceable]

this whole time I thought that the whine was coming from the alternator, I even called it the supercharged alternator!

[@project_amg]

I thought it was the power steering

[@Uninfluenceable]

@@project_amg the noise is quite different than power steering whine. It sounds more like a roots/screw type supercharger whine

[@nickmarshall2676]

@@project_amg mine is power steering. But also this pump noise. On baby benz m112k

[@lucasatsuoito7978]

Well, you can still call it the supercharged oil pump!

[@dreieinhalbeck]

@@lucasatsuoito7978 when you need to make the oil faster

[@roxxas5]

This guy out-German'd the Germans

[@adams4100]

Apart from the fact they will last about month.... they need to be made from steel....

[@hendrahendra]

@@adams4100 i dont think they do because those gears will have a constant film of oil and wont ever touch each other to wear down. Well, they will wear down but probabbly outlive the engine/car. Edit: spelling

[@nickopedia5669]

@@adams4100 How would they only last a month? They are on 2 individually driven, timed shafts. They literally don't do anything other than push against the fluid.

[@adams4100]

@@nickopedia5669 and each other.... we reproduce oil pumps and the gears are precision ground steel for a reason.

[@nickopedia5669]

@@adams4100 No they do not run against each other. It is the job of the other gears that are pressed on to keep the shafts synchronized. (the ones that pump only oil with no air entrained with it, and are precision ground from steel as you said because they actually operate against each other.) The lobe design he made isn't even capable of driving the other shaft if the other gears were to fail. If they were asked to do any work, it would literally just jam up.

[@000polsris000]

I'm a dealership Mercedes technician, and I always wondered what that noise was. This video is awesome! You've got a great modification there. I'd be curious to see how it holds up after a few tens of thousands of miles.

[@Vespastendert]

Lol same. Sometimes when i start one of them i make the noise with my voice 😜

[@ZZZHarpy101]

Longevity can be corrected by changing the alloy or the heat treatment used if it happen to become an issue.

[@archangel3237]

The new gears don't actually touch anything at all, no contact no wear.

[@lordhelmchen616]

@@archangel3237 cavitation will destroy anything. look up cavitation damage on ship propellers. those don't touch anything but water and yet they can get chewed up pretty badly.

[@LynxStarAuto]

@@archangel3237 lol that's not how that works bud. Everything touches *something* in this universe.

[@flippy9133]

Netflix: are you still watching? Someones daughter: 20:02

[@rensvanbreukelen3762]

Oh god

[@fila1445]

Bruh

[@Your_username_]

🤣

[@1uzfe]

This channel is a big motivation ☝️literally keeping me in engineering school without wanting to give up all together

[@Rogerfuk]

This makes me regret studying finance instead of engineering 😔

[@kasparsjansons9220]

@@Rogerfuk I studied mechanical engineering, and now I can't find a job 💪

[@CabronazoMotivado]

@@kasparsjansons9220 epic win

[@flemmings5534]

@@kasparsjansons9220 where do you live?

[@cade469316cw]

Keep it up

[@wreckervilla]

18:40 ah yes, the sound of german engineering

[@blanchae]

Press fitting aluminum onto a steel shaft - how does the difference in thermal expansion between the two metals affect the fit when the engine heats up?

[@xfmotorsports]

Aluminum expands more but the press fit is much tighter than it will ever expand to. I heated them till they started melting. Still remained tight

[@shaadydog1]

They should never be much more than 220 degrees like the oil in the pan....

[@cadgrampadavidb9853]

@@xfmotorsports I know it would mean additional machining, but adding a keyway to both shafts would allow perfect alignment of the lobe gears without any possibility of expansion related failure. It would also make assembly/alignment dramatically easier. For an alternate lobe shape, look up "Waukesha Pumps". These are food grade product pumps used in the food/dairy industry that are basically just large slow oil pumps. We used to use them to pump heated peanut butter to packaging machines. What a mess to clean up!

[@emmettmartin2639]

@Vivid Media yeah but not at any temp close to 220 degrees

[@Qujav]

More then that I would be in fear off electro-chemical corrosion, those two metals gives up some voltage together

[@poptartmcjelly7054]

Might be worth machining an assembly jig for the pump gears. Maybe just a bracket to hold the gears in alignment.

[@blipman17]

He could even machine three small alignment slots on the side of the gear, then machine an alignment bracket which keys into the slots. Then just press em both in at once.

[@poptartmcjelly7054]

@@blipman17 maybe not slots just holes for alignment pegs that would be on some thick backplate to use on the press

[@douglassenriquez423]

PLEASE HELP!!! Can you help me with putting my m113k oil pump back together? My car 8 the serpentine belt so I have the oil pump apart and noticed the stars and Dot's on the teeth of the oil pump gears but I do not know how they realign.... Can you please help me with this! PLEASE HELP!

[@johndoe1778]

Has a CNC but no press 😂❤️❤️❤️

[@camillosteuss]

Regarding the material chemistry, the aluminum is a poor material, as what wears the gears out is not the contact as they are made of the same material and are lubed, its the cavitation proces which is also part of the reason for your noise, as its imploding air by crushing it and doing that chunks the gears or the walls depending on the pump type, taking small fragments of material from the part where the cavitation happened... Aluminum being turd soft is not the best thing, especially for the initial gears which see the largest air bubbles... Steel should be used as was for the factory gears, but apart from the material, great design! I'm not saying the aluminum wont work, but it will wear out much quicker as the wear as stated above in pumps if ran lubed is rarely caused by the contact of the parts which are of same material, but rather caused by impurities/solids in the fluid pumped and cavitation process...

[@bowez9]

Cavitation is the real problem and the finite fatigue life of Aluminum. Further the is no reason to have made them out of Aluminum, no useful weight savings plus extra cost over steel. The only reason I could see to use Aluminum is machining time (assuming only having HSS tooling) but this shouldn't be a concern given the product and application. Now if you're building a car were every gram counts then this is a good idea.

[@liridoni123]

Yes I'm opinion like you say aluminum sound good but not in the right place for doing the job because one little piece of aluminum so to the crankshaft and the engine blloout.

[@colinbowman8816]

He didn't talk about the level of the press-fit either, or thermal growth. That bore is going to grow ~.0025" in operation. Will it still be a good fit with hot oil wicking in the material, lubricating it nicely? Will it crack from the stress when he parks it in a -20c lot? Steel really would have been the better choice.

[@TheCarpenterUnion]

Idk about steel..​Brass is usually used in the scavenge pumps that I've seen

[@realestateeric]

I actually love this noise! It's how you know you have a 5.5! When I got a C55 for my wife I was stoked to find it made the same start up noise as my SL55!

[@nickmarshall2676]

Should have got a c32! But hard to find

[@mkwmoe]

@@nickmarshall2676 No way! The C55 is so much more lovelier, it's still a hard find too! Both great cars though.

[@gixx3r]

Well done! This is some refreshingly straight forward trial and error mechanical engineering. Keep up the good work!

[@abreezy1016]

Imagine taking a shot every time he says “these gears”😂

[@taylorrobertson1016]

Alcohol poisoning within the first minute

[@taylorrobertson1016]

Death within the 2 minutes

[@brianhbinesh]

XD

[@osamahnajjar2824]

Now I'm only looking for "these gears", thanks to you.

[@brad3378]

The gears don't need to touch for brinelling to become a problem as unfiltered oil debris inevitably becomes embedded in the aluminum rotors as they squeeze together. The gears should be designed with cast iron or steel.

[@mjcapp2174]

I wouldn't use these without an oil filter installed for sure. Most dry sump pumps have aluminum gears and I wouldn't run without an oil filter with those either. Good point

[@Alex-xh1zi]

For getting the gears aligned on the shaft, a 3D printed jig would have helped get it spot on. SLA printers are very cheap now and are perfect for this sort of thing. Great job using your eyecrometer though!

[@douglassenriquez423]

PLEASE HELP!!! Can you help me with putting my m113k oil pump back together? My car 8 the serpentine belt so I have the oil pump apart and noticed the stars and Dot's on the teeth of the oil pump gears but I do not know how they realign.... Can you please help me with this! PLEASE HELP!

[@Guust_Flater]

For future scale up and ease of assembling....wouldn't it be a good idea to make your new gears parts fixed on the shaft using a key? Yes, you have to cut a slot in the shaft, but you can use the existing one as reference. Once the CNC has made this slot, the rest is "easy". Takening apart and reassemble wouldn't be a specialist, like yourself, to line it up perfectly. 👍Love your videos!! 😃😎

[@peglor]

Keyways must have play in them in order to be assembled, so, as well as adding more manufacturing steps and a stress riser that could initiate fatigue cracking in the shaft and gear, doing this will not locate the gears on the shafts as precisely as a press fit. It also add radial movement to the gears, which will likely create noise through imbalance as the gears will naturally tend to run off centre with the shafts, which can't happen on press fitted parts.

[@douglassenriquez423]

PLEASE HELP!!! Can you help me with putting my m113k oil pump back together? My car 8 the serpentine belt so I have the oil pump apart and noticed the stars and Dot's on the teeth of the oil pump gears but I do not know how they realign.... Can you please help me with this! PLEASE HELP!

[@alexanderneukam1065]

Well done ! Also, as you said, it looks like a massively higher oilflow - tremendous!

[@MotownModels]

This is a great idea, but what's the thermal expansion effects going to be like? Aluminum has about double the coefficient of linear thermal expansion compared to steel, so when submersed with hot oil for hours, could the new gears begin to slip from their press fit on the shaft and hit each other?

[@Smokkedandslammed]

I was wondering where your videos went! I was just thinking the other day I hadn't seen any updates about the car, this is just as cool!

[@boltonky]

Awesome video and its interesting how rotary style lobes (don't know what you actually call them) are coming back into fashion for water pumps / dry sumps etc. I learnt about them from my commercial rotary compressor only draw back from my understanding is tolerances play a huge part in them working efficiently or at all. Keep it up i shall be back to watch more

[@SkalabalaK6]

Be careful with that extra amount of flow, I've seen pump gears explode due to the resistance of the oil at high rpm. Awesome work :)

[@youmakeitwhatitis]

This concept intrigues me. I know oil pressure is largely formed by the bearings, so is there any way to keep the oil pressure down after you beef up the pump? Do more/bigger oil passages do anything about oil pressure? What if you simply used a smaller pan and reduced the amount of oil in the system? Less oil would mean the pump will have periods during which it pushes less or no oil, so I'd guess that's actually a lubrication concern for the pump and the bearings, not to mention a concern for the longevity of the oil between changes. Thoughts?

[@timramich]

@@youmakeitwhatitis Higher pressure means the film layer in the bearings can support more load. Not a bad thing at all. The only cost is power to provide that pressure. Probably minuscule.

[@atsernov]

@@youmakeitwhatitis All pressure pumps have a bypass of some sort to control pressure; usually part of he pump but sometimes fitted in the main oil gallery. If you increase the flow of the pump significantly, you then need to increase the size of the bypass. However, since this is a scavenging stage, there should be no significant pressure. I don't think that's what the OP had in mind though. I think he is talking about surface tension. The faster a solid strikes a fluid, the more that fluid behaves like a solid. Hit a fluid fast enough and it can well be "harder" than the solid that hit it. I can see how this property could be a problem in a scavenge pump at very high RPM.

[@angreygt3508]

He hasn't altered the pump or output performance of the drive pumps, only the transfer pump in stage one that's essentially a siphon from one sump to the other. Frankly the whole system is a little overdesigned, as an easier way is to simply have a larger sump and more oil (which is better for cooling) and then the active pickup is never starved for oil. Anyway, this modification will only affect how quickly the stage one pump transfers and dries the first sump and keeps the active second sump fed. As he states in the video, the face cut gears were much quieter when moving material, but the motor spends very little time in that condition, once the stage 1 moves all the available oil from that sump, they go dry/partially dry and whine loudly from then on. The active side pumps (that push oil pressure to feed the motor) weren't changed other than fixing the second set of gears to act as the drive gear for the second shaft. That should have negligible effect (if any) on the pump characteristics and performance of the active system

[@kevliong2952]

I think you underestimated the wear it is subjected to from picking up dirty oil from the sump. Bold move making it out of aluminium.

[@thomasaltruda]

Lycoming aircraft engines used aluminum gears early on.. they had issues and changed them to steel. Interesting test he did here, but steel is better.

[@n.shiina8798]

thanks for the laugh material on that stock pump. what about using key instead of press fit for both ease of assembly and serviceability?. or key on one side and locking screw on another side for adjustability?

[@aqa321]

Oh how I miss that noise. Each time I hear it I regret selling my old SL55....

[@BorisBidjanSaberi11]

I think of my first time I sat in a C55 Wagon....

[@olliesgaragebyfp6275]

Found your video on KZbin suggestion. You guys are amazing. Keep it up.

[@forrestcarroll9350]

If you plan on doing more of these you could make an installation fixture which both gears sit inside of in the correct orientation, center distance and axial offset offset so you can press fit both at the same time, that should remove any potential for them to be out of phase. It would basically just be a stepped piece of material with a close tolerance to the outside of each gear and two through-holes so you can press both to full depth in one operation.

[@NNFaNRacing]

I'm surprised it was worth it to go with aluminum rather than a more thermally stable metal like steel. With steel couldn't you tighten up the clearance between the gears more because they will expand less, ending up with a more efficient pump?

[@endeavour2127]

Awesome video! There's nothing you can't solve!!! Keep up the good work!

[@AMGmeister]

Very interesting! Great video.

[@TheKeenMechanic]

Amazing engineering. Well done mate

[@ikocheratcr]

Great video and explanation about the noise source. I thought this noise was coming from the chain. My W163 which has a M112 has little noise, but my w210 M111 has way more winning noise, and mostly on idle. Now I know ...

[@machinist1337]

As a machinist, I would say that the use of aluminum in this application is insufficient. I would be very worried about the aluminum spinning on the shaft causing catastrophic failure. That being said, your ingenuity and execution was spot on. You did a really good job. I dont know what cost is associated with producing these lobes, but im assuming less that 50$ for material and machine run time. Take a lobe and a straight cut gear to a tool grinding shop they can precision grind id and profile with tighter tolerances and better press fit. Very awesome video! And the shop cam select the correct material based on hardness of straight gear.

[@Truthcanbeconfusing]

dude you're killing it!!!

[@TysonEngineer]

love this one man!, great work!

[@cadgrampadavidb9853]

What type of CAD software are you using for the CNC design/programming? If you already know 3D CAD (Inventor, Solidworks) is it difficult to learn?

[@mrh3085]

Just curious if this vast improvement in oil flow could cause over pressuring elsewhere in the system? Thanks for your talent and patience in creating this product and video.

[@steveman1982]

Wow that was an unsettling noise it made before the fix :D

[@Uninfluenceable]

pretty much every MB from the early 2000's have that noise. The loudest I have ever heards was always from the W203 C240's

[@Erteywie]

not an unsettling noise when it's been there since day 1. Mechanical whining is.. different.

[@shaadydog1]

Whoa, did you consider like a twin screw design where you have 2 different lobes that fit to each other? Or a slight helix to help compress from pan side to port side?

[@bigtrucksfastcars745]

What tool did you use to press the chain sprocket back on the oil pump

[@liridoni123]

Can l ask you one question where did you learn about all these things I'm allso mechanics you inspired me I'm from Kosova and i fix all mark's car bye.

[@Doktoreq]

Have you factored thermal expansion of aluminium in your design? If not you could have problems when engine oil gets hot - press fit could get loose because steel shaft expand less than aluminium gears and tolerances between gears could shrink too much.

[@sepg5084]

Yes he did

[@master6435]

Would give the gears a twist similar to a roto/twin scroll style supercharger help with increasing oil pressure to?

[@bigthecat1808]

This channel needs more recognition

[@akuhafiz1128]

VERY VERY EXTREMELY CRAZY GENIUS BRO

[@dadagogo7839]

Can changing the type/weight of engine oil help reduce that whine? Is this procedure any easier on the M113 motor?

[@meritonberisha3871]

Will you fit these to any of your cars for a before and after comparison?

[@elektrosmokes1911]

I used to love that pump whine when I had my 55K way back in the day. lol

[@albertorobinson7611]

Can you explain some of the volumetric approach of the drysump system in this engine

[@BlahBleeBlahBlah]

Awesome work! I always thought that whine on a lot of cars was a worn hydraulic power steering pump! Interesting to know it’s actually the oil pump.

[@dominicnocon4]

This is what happens if you never stop Formula SAE haha

[@anythingbenz4005]

So this whole time on my E500 it was the oil pump making the whine? Do you know if E500 use the same oil pump ?

[@peakperformance8960]

Is this only an issue for the E55 and CLS55? I have a 2004 S55, wondering if they have the same issue?

[@philipcooper8297]

What kind of oil pressure and volume you get with your pump?

[@hashemmatter5389]

Can I ask if you have your own cnc machine ? And what system do you use ?

[@milkforcoffee]

Straight cut gear is more commonly known as a spur gear. Love that you did this.

[@modified5047]

Would it be a problem if the scavenging and second stage was replaced with these gears?

[@cyronader]

wow! will this work on the m112 engine too?

[@MrJellyGhosty]

Love your channel!

[@azargelin]

Been waiting for a vid

[@DenysSene]

despite the clearance, did you consider material dilation when running?

[@abea4696]

For years I couldnt figure that noise out. 👍👍👍

[@alejandroloterono7602]

it is similar to root blower. to reduce the noise use helical gear instead of spur gear the pair you're using, but assembling with helical gear is more tricky

[@jameswoodsist]

really curious about how the aluminum gears hold up. im not sure wear is the only concern, my first thought was cavitation damaging the peaks and valleys of the gears (where cavitation is most likely to occur) i wonder what a set looks like after a few thousand miles.

[@dgpgarage9291]

Awesome job, very complicated work to get it right.... are you worried about cavitation damaging the lobes over time? I’ve seen it damage steel gears over time, not sure how aluminum will hold up

[@tommysimon9353]

Man, you made my day. I own and drive a M272 with this whining noise for about 10 years now and was always wondering what it is. As I exchanged the timing chain and pulleys for some other reason 😎, I already suspected the oilpump and it‘s drive chain. As always: excellent job, nicely documented. Thank you very much!!

[@LynxStarAuto]

272 is a different engine, and uses a different pump. 272/273 doesn't suffer from this problem. Check your drive belt pulleys, AC compressor, or PS pump. Those are the main culprits for noise on that engine.

[@johnmcclain3887]

That is a substantial display, the additional problem is the standard gears break down the long chain molecules that give viscosity, much faster than your design because you don't put the oil in "shear", a real problem with hot engines, lots of pressure, and there is no recovery when the molecular structure is broken, cooling doesn't restore viscosity, and it foams far faster than "sound oil, unscathed". Very much different. Thanks for the demonstration.

[@Rourkeize]

Is it the same pump as on older M113 engines?

[@cristianbustos4918]

what oil pressure you get on hig rpm?

[@Chirpy_Ceilingbird]

I got to drive an s63 coupe around for a few months when I was in Southern California. Miss that Mercedes.

[@taranraja9819]

Pls do an video on the E55 ASL project cost for all the parts and future plans

[@georgerobartes2008]

Interesting gear design taken straight from multi lobed superchargers ( Rootes, Sprintex ) that have been around for many decades . The supercharger rotors are actually machined helical but theoretically they too , do not actually come into contact with each other except when there is an idler gear backlash and contact. The Sprintex units have coated rotors . Basically a pump is a pump whether hydrodynamic or aerodynamic . An improved version of this pump would incorporate the helix .

[@thomastymrakiewicz7381]

Well done!!!

[@mohamedyasinarakkal5130]

Hey shehryar so the s55 and cl55 doesn’t have the two oil pans that the e55, cls55

[@FrankoZetto]

do you make part for 300zx ?

[@naknak2473]

What software are you using?

[@ademc8872]

I don’t mind the noise, as long as it doesnt fail and its solid😁

[@GoldPitbulla]

Can you use a high temperature plastic?

[@FixItRyan]

Non-AMG M113's have this too! I've wondered my NA CLK500 made this "supercharger whine!" Good to know!

[@gman3725]

Love the dish washing gloves!

[@sethgt1234]

It's really hard to improve on German inginering. Awesome job!

[@lukef13]

Will this work for 2005 clk 55 amg oil pump?

[@59sttrackplayer80]

Does every Benz have this type oil pump gears or just the 55 AMG??

[@6ix13ree]

I have a 06 C55 , do you have a fix for this model?

[@johngaltline9933]

So, is the speed difference we see in the input shaft due to the added resistance from the old gear's friction fitting? If actually spun at the same speed is the flow actually that much higher? I would think the volume of oil pumped would be equal to the engagement area of the teeth times the number of teeth. Without the exact numbers it's hard to say, but it looks as if there is less 'total tooth volume' per rotation on the new design which would equate to less oil pumped per turn. When spun by an engine that won't notice the torque difference needed and that is set to maintain a given RPM in any case, I have a feeling the flow rate is actually lower on the new set of gears.

[@northerner1374]

Skills 👍🏻 wonder what the long review will be? 🤔

[@eformance]

You could make a special press tool that holds both of the lobed gears in the proper orientation and allows both of them to be pressed on simultaneously. Also, since you used Aluminum, heating the lobed gears will make installing them much easier, they should FALL into place if they are heated, avoiding the need for pressing altogether. Combine heat and an installation jig and you'd have a relatively easy installation process.

[@xfmotorsports]

It's a very tight fit. You can't expand aluminum that much without melting. Making a fixture might make it easier but because of the backlash in the gears it still won't be a 100%, unless the gears on the other side have a fixture as well

[@eformance]

@@xfmotorsports What is the interference fit?

[@eformance]

@@xfmotorsports You can add shims to either bias the lash to one side or center the gears to divide the lash, then install the lobed gears on center.

[@xfmotorsports]

@@eformance I believe it was 2.2%. Aluminum expands around 1% max. Yeh shims could have solved it

[@douglassenriquez423]

​@@eformancePLEASE HELP!!! Can you help me with putting my m113k oil pump back together? My car 8 the serpentine belt so I have the oil pump apart and noticed the stars and Dot's on the teeth of the oil pump gears but I do not know how they realign.... Can you please help me with this! PLEASE HELP!

[@camclarke567]

I found this extremely satisfying

[@Julianray91]

Legitstreetcars would love this

[@bernardwarr4187]

Very good design and engineering Very impressive

[@georgobergfell]

I wonder if the M111 engine has the same pump design, since mine sounds exactly the same on startup. I always thought it was the power steering pump

[@xfmotorsports]

Remove the serpentine belt and start it for a few seconds. If the noise is still there then it's the oil pump.

[@hammerphilosopher]

Let us know, I had a m111 too and I always thought it was the supercharger..

[@headontoast4510]

Heaving a dot here, also got a M111 with this noise.

[@armyman8889]

Same here, also got the M111 sc

[@minercraftal]

Could anyone tell me where can I find this pump rotor shape, I think I might need it... is it from a 3d mode website?

[@TA-mm7rv]

You are a genius 👍

[@user-oj4xh8cg2l]

How long do you expect these gears may last ?

[@skidwilliams9451]

So you thinking about a complete package switch out and a customer ships a core and you assemble all? Charge a core return? I have a sl55 and would have interest to do this as long as I had to only put the complete pump in. Great video. Great content!

[@haas4262]

My c55 makes that same noise. Never thought anything of it haha

[@draggonhedd]

Yeah but what kind of *pressure* can it maintain?

[@droman752]

Great job! I wish I can get into the Mercedes scene now!

[@crazeguy26]

$1000 you can get a broken Mercedes.

[@KindredAutomotive]

Wow! Awesome work! Do the regular 5.0 engines use the same pump? All our E500’s make a similar noise and it’s always drove me nuts.

[@modified5047]

Yes. Its the same scavenging section.

[@mohabatkhanmalak1161]

The three lobe pump has been out there for a while and companies like Komatsu, CAT, Hitachi etc have been using them in their hydraulics. But you have shown a good application in Mercedes Benz engines to rid of the whinning noise. Maybe you could get in touch with Daimler Benz AG, their head office and show these improved results and who knows they might use this designs in their engines. The only concern is the higher flow (so the pressure release valve needs adjusting) and using the softer aluminum for the lobes. The aluminum could wear out due to cavitation and friction from molecules of oil. Steel would be a better material. Finally, you can time the lobes perfectly and easily by using a jig to line them up while assembling. And if you have ideas that have not been patented before, register a patent or design and reap the benefits of your invention.

[@stevebez9556]

The straight gears have the noise at startup only and then quiet down quite quickly. Is this because the pump is saturated with oil or all the oil has been scavenged from the front sump? And to be clear this 'new' gear chamber just moves oil from the front sump to the back right? It is a very annoying noise tbh - and having it quieter is much preferred - its just a bit difficult to pick up the different noises generated with the impact gun in the background! Do the other straight gears also make this noise? Why is the front gear the loudest? Personally I would have made the gears out of steel - but I assume this is just a case of changing the base stock during manufacture? Press fitting ally onto steel gets me a bit worried about the ally fracturing over time - when under load for many hours and heat cycles especially given the very tight tolerances.