GMC 4L80E LOSS OF OVERDRIVE, HARD SHIFTS, ACTUATED FEED LIMIT BORE IS THE ISSUE. Read description.

Tranny on my 2000 GMC C3500 would work fine until worm, at which point I'd lose overdrive (4th gear) and would get a jerky shift from 1 to 2nd and 2nd to 3rd, I found out my harness plug was leaking, it's not the O-ring it's the plug socket itself on transmission side wicking trans oil through the plug, shorting out connectors. I JB welded the inner side of the plug, leaking stopped BUT did not fix the issue, which actually is caused by ACTUATED FEED LIMIT bore being worn out. To fix it valvebody needs to come out.
Parts needed for this are
Sonnax Transmission Actuator Feed Limit Valve Kit PN: 34200-16K - $42 on Amazon
Reamer Transgo PN: 48-act-tl around $100
While in there might as well replace Lube Valve Sonnax PN: 34200-14k around $60
Also two gaskets along with plastic check balls if balls "bored out" the holes on the gasket.

[@Trainreck99]

Hi. Thanks for the video. I have all the problems you can have with my 1993 K3500 6.5 turbo diesel. NO OVERDRIVE and HARD 1 to 2 shift and HARD 2 to 3 shift. No overdrive had me hitting just at the red line at 3500 rpm to get 60 mph. FIRST thing.... I am also certain this is an electrical problem. DO NOT panic. Before you buy bunches of parts and hours of troubleshooting try this very simple thing. Disconnect both NEGATIVE cables from each battery. Just disconnecting one negative cable will not cut the power completely to your truck. In a diesel there are two batteries. So make sure everything is dead by disconnecting both battery negatives. Wait for at least 10 minutes to make sure all electrical components drain off power. I do not know how long it should be disconnected so I would just let it sit for 10 minutes at least. Reconnect both negative battery cables to each battery. Start your truck and let it warm up a few minutes. Take is for a drive. This fixes my truck for the hard shift and NO Overdrive. Everything should function normally. Enjoy! This is only a remedy and doesn't necessarily fix the actual components on the truck. I used to be able to stop truck and turn on key and restart to fix this. Soon this will not work anymore. I cannot guarantee this will work for everyone in all Chevy trucks. I hope that I can find the actual fault soon. You all can help me with that. But you have absolutely nothing to lose but about 15 minutes of time. And it doesn't cost anything to try! Hopefully you all have nice fresh batteries with clean connections and good grounding. Have a great day!

[@jonathanramirez6541]

Great tip bro work on my truck

[@Wildkat-1]

A new harness is easy to install, that's the best way to fix it....those plastic gang connectors are bad about cracking from heat , they will keep cracking and leaking....fix it right and be done with it..!

[@ronclaman156]

To all you beginner's use a socket slip over plug from outside it squeezes the fingers down and you can pull it right out ..... work smarter not harder...LOL

[@markfranseen9272]

My issue was eratic shifting, then sticking on one gear. Send codes for 2-3 shift slolenoid and throttle position sensor. Replaced the shift solenoid, no help. Then I got even more codes, like 41 of them for every weird thing. I saw your video and" checked my plug, full of oil. Cleaned it with q-tips and air and put it back together and it shifted fine. I'm going to see how long till it leaks and shift wierd again. The make a "Pass thru connector" that simply seals the female end of the connection and allows the plug to connect to the other side but I can't find a 1998 Chevy 4l80e one. Thank you for your video!

[@vernoncook8897]

You a freakin life saver. Thanks for tha video. This was my exact problem

[@jordanotto2611]

So the part that he's JB welding is actually called internal wire harness

[@JesusGuerrero-fe3du]

How did the fix go we need an update on this fix did the plan work I am having same issue I wanted to clean it up and maybe put black silicone let it dry and then install

[@kentuckyrain2223]

I would have used black rtv sealer it would work great

[@bowtiebuilding]

Yep! Black silicone (RTV gasket maker) is what I do with my 4L80E’s!

[@jordanotto2611]

Cuz I just got done putting a different Transmission in mine before I lady and I don't have any speedometer and I have oil leaking out of there so one I got a bad speed sensor back there I need to be replaced and 2in needs a new internal wire harness all together the parts cost me about $97 and literally about an hour worth of time now that I've had my truck apart a million times KZbin don't show these videos which I've been debating on whether it's starting a little KZbin channel and making them for the 4 L 80 e and the 4L60E

[@edgarsoto4063]

Did you figure it out? I got same issue New TCM New ECM Rebuilt transmission Leaking oil out conector, check engine light on Shift inhibited / engine reduced power

[@chestercountyjesus3702]

Got a 91 burb with a 4l80e that was doing the exact same thing. It would drive fine when it’s cold and hard shift into 2nd when warm and would kick out of od down into 2nd. Turns out the last owner overfilled the trans, so I drained some out and added a bottle of trans x to it and it solved my problem. No more hard shifts and od works fine

[@bobbyatman273]

Wow, well "lucky" you! Lol, transmission shop would have a very good time "fixing" your tranny and parting right after if not your DIY skills, but for majority of us unlucky ones it's an AFV valve that worked it's bore to loose fluid pressure thereby instructing transmission via solenoids to drop 4th gear amongst other symptoms.

[@onedownproductions4289]

Thank you very much! Great find for me. I have 1994 GMC same tranny, thanks again

[@myguitaryourface5160]

Nope 96 and up not the same as 91-96

[@davidmorris4311]

How did replacing the acuator feed limit valve go? Were you able to do it without removing the entire trans? And did you have code p1870 before changing it?

[@bobbyatman273]

I bought an updated valve body off of eBay with updated a valves and solenoids for under $300 and replaced it myself literally on the cardboard on the ground by the truck, all went great. No need to take the whole transmission out for this one and there were no codes it was acting up.

[@kennethedwards3120]

Did u every get yours fixed having same issues and also got the code I was thinking this is electrical only tho

[@anthonycaldwell5176]

I'm having the same problems I want to know where you jb weld it and any other tips to get it fixed

[@SGaryNinja]

The Transgo reamer kit includes new valves. Is the Sonnax kit that much better? Also, the Sonnax install kit is $280 MSRP and includes some guides. Are those necessary or is the trango kit that includes the basic reamer enough to get it done safely?

[@bobbyatman273]

I looked at those kits but just spent $300 on reworked valve body with new solenoids and valves including AFL valve, made more sense to me.

[@gregsilva1472]

Do you know the part number for the big Oring around the plug that’s where mines leaking?

[@jensenjones1193]

I have 05 Chevy Silverado 2500 HD (4l80e) got the transmission rebuild. After I got it rebuild it was running nice for 3 months and out no where Engine light turn on and a code pop out, code po757 shift solenoid B loosing 3rd n 4th gear( limp mode). So I replaced the shift solenoid A and B, thought would fixs it. But still loosing 3rd and 4th gear (limp mode). So idk what's the deal with it n hoping you would know my problem.

[@alkarim5890]

I’ve just got the exact same code issue last night, by the way it says shift solenoid B stuck on ! Were you able to figure it out ?

[@shuandale]

I have a 03 Silverado doing the same thing, glad I saw this saved me lots of money

[@proud_american859]

I also have an 03 Silverado

[@poliyovalencia247]

U fix the problem

[@miket43mt]

03 Silverado, same problem

[@DanMcD80]

Oil in the plug on a 4L80E is known to cause limp mode

[@bobbyatman273]

True, but was not the issue in my case, Actuator Limit Bore is the issue, go through my description.

[@DanMcD80]

@@bobbyatman273 oh I know but for others that read the comments to figure out their issue

[@Alex-dn5hi]

so the actuated feed limit bore is causing the fluid to be pushed out of the plug? I read the description but you also said in the video the issue stopped for about a week when you cleaned the plug. I'm confused..

[@bobbyatman273]

Sorry for confusion, when I JB-welded inside of the plug I ran around the city for a week and everything seemed fine until I took it on the highway, so that did not fix the issue, it took me a bit to find out what the problem was and it was actuated feed limit bore being worn out, it had nothing to do with leaking plug, but I decided to eliminate it as a potential culprit, please read my updated detailed description. Thank you Regards

[@papasmurf4328]

question, did you still have reverse? like would the truck move on its own power in r? im having this issue

[@bobbyatman273]

There is a reverse gears and controls inside transmission, it could be mechanical or electronical, problem can be in your valve body.

[@joephillips8817]

Got the same problem in my 91 suburban and hopin its just a solenoid

[@alkarim5890]

Hi Sir, I’ve just replaced the wire harness, all the solenoids connectors went smooth but the big main wire harness connector won’t come out ! I try to pull it out gently with channel lock but it’s not getting anywhere, the tabs can’t come out ! Any tricks on how to get that connector to snap all the way out flushed with transmission body ? Thanks in advance.

[@bobbyatman273]

You need to get a socket (I don't remember which size ) put it on the tabs and push on it so that all tabs get squeezed inside simultaneously, it's actually easy, ones you get the right size socket, push on the socket and at the same time pull and wiggle the harness. And don't forget to change the O-ring on it too.

[@alkarim5890]

@@bobbyatman273 i already got the old one out. my problem is to get the new one in, it only goes half way then it gets stuck ! No matter how i press on it !

[@bobbyatman273]

@@alkarim5890 hmmm... I've been selling used auto parts on ebay for over a decade, many people order wrong parts, you have to go by a part number, not just year make and model. Now...compare the 2 connectors, your old one to the new, are they same?, feel with your finger in the plug opening if it's clean and free and clear of garbage, use a bit (not too much) of force- new plug with new O-ring may require a bit more force to get in its place...

[@alkarim5890]

@@bobbyatman273 Thanks Bobby

[@stephennix4644]

I’ve noticed I’m leaking transmission fluid very slowly and it seems to seep out from the internal harness. Hopefully it’s just the connector and not the actuator limit bore. I wanted to ask how much fluid would you loose?

[@bobbyatman273]

BAD ACTUATED LIMIT BORE WILL NOT RESULT IN LOSS OF FLUID, IS YOUR TRANSMISSION ACTING UP? AMOUNT OF LOSS OF FLUID DEPENDS ON HOLES IN SEALS.

[@CrystalLedeay]

Ok well I guess everyone is asking you whats wrong with theres. So any suggestions on mine. Its a 94 chevy g30 camper van with the coachman camper I bought I and every gear shifts ok except OD. I changed the filter and tranny fluid it was black but no metal in it. The tranny looks old and rusty but it only has 120,000 miles and the engine runs great! There is some really soaked hoses right infront of the tranny not really sure where it's coming from guessing the oil its close to the oil filter. I had no speedometer either for the first week but it started working and when i get to about 45 my cheeck engine light will come on when it doesnt shift I slow down it'll go off keeps a antibrake light on I'm not sure why my brakes work fine. I did notice it look like the transmission might of leaked a little after I changed the fluid so thinking it might be that plug. I'll change that oring and clean it and check the harness but I'm thinking it might have something to do with my speedometer not working as well. Maybe electrical because of the engine light coming on and off?? I'm not sure ans I'm just a Girl! Lol But I need some suggestions before I change the tranny. Thanks in advance!!

[@chadanderson7134]

My Chevy is doing the identical thing. What else did you do to fix it

[@bobbyatman273]

Nothing else, just replaced a whole valve body with updated one from eBay

[@JesusGuerrero-fe3du]

Maybe your idea works better for me with the JB weld

[@anthonycaldwell5176]

I'm planning on replacing the wire harness for a 1991 GMC Sierra 2500 any help

[@smokey210210]

What j-weld did you use

[@bobbyatman273]

Just regular one you can find everywhere, epoxy and hardener, same thing fixed my hole in the oil pan too and its on solid and no leaks as well

[@ronclaman156]

Also buy a quality product such as sonnax or rostra .... so do it right the first time!!!!!

[@fixortow]

Update did it work did it keep leaking? I'll replace 3 different type of harness 3 different manufacturers and still leak.😡😡

[@bobbyatman273]

mine is sitting with a blown motorr now, in yours find a thicker oring and use lube to get it in, or you have some deep scratches where plug goes into a hole.

[@tommarkle7951]

Did this solve your problem

[@DanielRodriguez-qc4xs]

I'm having same issue with 4l60e, do you know if it would be the same thing?

[@bobbyatman273]

I'd assume it is, but I'm just a diy-er...

[@DanielRodriguez-qc4xs]

@@bobbyatman273 ya me too

[@billmonroe8826]

jb weld is a bandaid. buy the harness

[@bobbyatman273]

Its a "band aid" that outlasts band aid - i call it Russian fix, why bother replacing stuff? I personally don't give a darn for common knowledge, this "band aid" will outlast me and my truck for sure.

[@cliffharris1447]

So did it end up working?

[@LazySix]

Any update after trying to seal it?

[@bobbyatman273]

It was sealed with JB Weld nicely, leaking stopped, but did not fix my problem, it was Actuator Limit Bore being worn out, go through my description that includes part numbers.

[@Freedmevr45]

Are 4l80E transmissions garbage 🗑? I thought about replacing my th-400 with one but not if they are 💩

[@DanielRodriguez-qc4xs]

A 4L80e is just like a th-400 but electronic

[@benjaminp6924]

4L80s are great, especially when setup as full manual, just my opinion though

[@bobbyatman273]

@@benjaminp6924...everything is great until human touches it

[@cantyoufeelthelove]

They are great transmissions and if you ever go wanting power they can handle it. The 4l60e is the weaker of the 2, but usually helps mileage like the 700r4. Like Daniel said it's basically a th400 except it does have upgrades internally. Also check out transmission bench. Dude has a great video for like cheap and you can learn to rebuild your own.

[@ronclaman156]

They are a great transmission I run one behind 700hp engine .. 5 years no problems I'm don't treat it nicely pretty rough on it.. I change fluid and filter every 30 to 40 k miles

[@anthonycaldwell5176]

Transmission wire harness

[@juliobichao7588]

What year is your truck? Question is for the video poster

[@bobbyatman273]

2000

[@juliobichao7588]

I’m having the same issues. I’ll drive the truck for 5 to 7 miles and then it kicks out of overdrive. If I shut the truck off and turn it back on, The problem disappears and then appears again after 5 to 7 miles. After seeing your video, I pulled my plug and it was soaked with oil. I cleaned it out really good with electric parts cleaner and compressed air. But it did not change anything. If I unplug my my tps it will stay in overdrive but it won’t downshift at wide open throttle. I’m on my 3rd tps thinking that it is the problem. I’m stumped.... Did your fix work out after the jb weld? I think jb weld has metal particles in it. It may conduct signal between the wires on the plug.

[@bobbyatman273]

@@juliobichao7588 I was going to update my vid, what I did did not fix my problem, I found out whats really causing this issue its the actuated feed limit bore in the valvebody worn out, look up "4l80e - loss of 4th gear" on KZbin and "4l80e valvebody repair and vacuum test" The valve body needs to come out and that bore needs to be reamed with a reaming kit. You need AFL (actuated feed limit) kit pn# 34200-16k Reamer pn# 48-act-tl You might want to also replace Lube valve # 34200-14k And anything else while valvebody is out. These part numbers are for 4l80e transmissions.

[@bobbyatman273]

@Ben Hey Ben, lve just bought an updated valve body from ebay for around $260 that already included updated actuated feed limit bore valve and new solenoids and just replaced it. You can replace your own solenoids but to enlarge actuated limit bore you need $130 bit and you have to bore the hole yourself.

[@dogpatch8266]

quit dic... around, spend the $40.00 and buy a new harness

[@bobbyatman273]

This was not about a harness, it was fine

[@jamesboudreaux2989]

2000 chevy 3500 hard shifts no passing gear no regular over drive and transmission rebuilt unplug transmission plug no problem but the passing gear it doesn’t shift idk brand new motor and transmission 🤦🏾‍♂️🤦🏾‍♂️

[@LazySix]

Test the rear speed senser

[@jamesboudreaux2989]

@@LazySix nothing i come too figure its in the harness somewhere

[@bobbyatman273]

Are there any codes?

[@jimmydollard2750]

ehhh i