4L80E Basic Rebuild - Part 1
Вставка
- Опубліковано 13 лип 2024
- This video series shows a basic rebuild on a 1994 model year 4L80E step-by-step, including build profile, parts selection and rationale as well as all case prep and gear train assembly procedures. I also cover measuring and adjusting rear gear train end play, direct and forward drum assembly
This series is a great reference for the DYI or transmission builder whose not already familiar with the 4L80E and wants to know what should be done to one of these transmissions in a stock or mile performance application.
Table of Contents:
1. Parts Selection (Overview) - 0:00
2. Case Prep: 8:33
3. Gear Train Assembly and Planet Spacing: 22:06
4. Rear End Play Adjustment: 57:43
5. Center Support: 1:02:25
6. Direct Drum: 1:11:19
7. Gear Train Final Installation: 1:36:10
8. Low Reverse Servo - Adjustment and Install: 1:45:26
- 4L80E ATSG manual: atoc.ru/uploads/manual/5fad1c...
Blind Hole Bushing Puller Kit:
www.ebay.com/itm/315134134355...
Looking for a 4L80E high performance rebuild?
- Check out my other series here:
• 4L80E Performance Rebu... - Авто та транспорт
invaluable aide to my assembly, thanks for the video. my problem is when i put air in the center support, the clutch isn't compressed against the spring, air just leaks out, not enough sealed in to hold air pressure and push the piston against the spring pack and close the clutch plates together. I know i gotta plug the hole(s) with my finger and I am, but the air is just coming out somewhere in the middle. i put 3 sealing rings on the center support, leaving one out for the dual feed, since it didn't work i put a seal on the dual feed 2nd from top ring and clamped it with a worm gear clamp overnight to compress the nylon. gonna work on it again friday and get back to this post late that night. any advice appreciated.
also, my 02 4l80e from a gmc 1500 HD sierra i'm pretty sure didn't have a cone shaped cushion plate underneath the clutch stack, and my rebuild kit didn't come with one, but i'm learning my year transmission was supposed to have one? only 91-96 didn't have cushion plate???
thanks for y'all's time.
Hi Jacob,
Pull the piston out and check the lip sealing surfaces on your piston (im assuming you have a new bonded piston - if not, obtain one)...Also make sure the sealing surface in the drum isn't compromised in any way or the inner diameter of the direct drum doesn't have sealing ring groove wear. Also make sure the sealing rings aren't compromised in any way...
For dual feed, there should be no center seal in the drum but the piston should be sealing as well as moving when air is introduced as long as the high-reverse feed hole is plugged in the center support. Otherwise air will go into the direct feed and come right out of the high reverse feed, piston will not move.
How much PSI were you using for your air?
I like to at least have 75 psi when air checking, esp when dual feeding something since more air charge is needed, generally speaking.
Awesome!!
Thanks!!!
Are the support rings necessary? I definitely dont remember installing them
Hi, what support rings are you referring to? The center support's sealing rings? If so - yes, you need them if you want reverse and 3rd gear as well as lube oil to gear train components.
If you're referring to something else, let me know what that is and I'll respond...
Thank you for watching, M F.
For the reverse servo: I am measuring using your method, but Im probably quite a bit heavier lol. How far am I pushing this pin down in the bore? It appears as though you are applying force until the output shaft moves, is this correct? Or, rather, are you applying as much force as you can?
The reason I ask is, I have been applying as much force as I can. What happens is, I get a rather large measurement for my servo travel: .190" - .205", which is fine but I'd like a little less.
However, when I actually bolt the servo cover down, the output shaft has some drag on it. I took the center support out, and watched just the reaction carrier interact with the band. With the servo cover bolted down, the band is clearly applied completely to the reaction carrier; it cannot move even when I rotate the input shaft. Instead, the sun shaft rotates the opposite direction, just as it should when reverse is engaged. This tells me I should have too little travel (
Hi Jet Black,
I never measure it with the center support removed as the center support centers the planetary carrier in the bore so your measurements may or may not be accurate (same principle applies to the 700R4s/4L60Es and 200-4Rs with the pump and center support, respectively.
I use all my weight and measure the travel from rest position to full stop; I typically don't look at the output shaft as that can begin to move before full stop but if I'm stopping when it begins to move, that's just coincidence.
Ideally, I don't like to see more than .175 but that piston has a lot of room to work...
@@nickstransmissions Thank you. What should I do about the band fully engaging the reaction carrier when I bolt my servo and cover down? That means I should grind some off the pin, correct? I just worry about doing that as I'm already well past .175" (.190"-.205") of depth from the cover mounting flange. If I grind any more to prevent band engagement I'll end up well under the spec.
If the band is applied once you bolt the servo cover to the case (I'm assuming you're installing the metal cover-to-case gasket) then yes, you would have to grind on the pin a bit until it no longer binds up the band onto the drum when not applied.
That said, I doubt it is actually applying the band unless you're not installing that gasket as that will make a difference. If your travel is .190-.205 you absolutely should not be binding...Double check before doing any grinding and make sure the center support is installed before doing any checks.
Another great video Nick! Having trouble locating that gear train lifting tool you used. Can you provide any info on where to find one? Thanks!
thanks, Chris! I looked at all the usual places and cannot find it either...I can reply back later with the dimensions if you want to try to make it yourself...Alternatively, you can use welders vise grips, just be careful and make sure they are clamped on the intermediate shaft really good.
Awesome job built my first, but what brand stand mount is that”Sup…….” ??
Thank you, Dantae! The manufacturer is a company called superior machine and fab, llc. They are out of Salt Lake and can be found on eBay: www.ebay.com/usr/superiormachinefabllc
When I set the end play on my early model 4L80E the rear output was roughly 10 thousands and the front input was roughly 15 thousands.
And the front end play is net of the rear end play and input shaft-to-snap ring-to OD planet base plate travel? If so, awesome - that's ideal. Nice work getting it dialed in.
I have a 1992 4l80e. Transmission shift fine but I've been noticing the truck will start moving (under 5 mph) then it will stop for a few seconds and then its fine. Fluid is good no black sludge in pan. Just wondering if its time for a rebuild or if it's something else. Thank you for any advice.
Hi Perry, thank you for watching.
That could be a partially clogged filter, slipping OD roller assembly, slipping forward clutch (sealing ring grooves worn into the inner dia of the forward drum) or gear train degradation.
You can drop the pan to see what, if anything, is at the bottom of it and go from there. Another thing you can do is a pressure test in combo with a test drive with a two-way scanner that shows live transmission and engine data to see if anything unusual is displaying in the data.
Thanks for getting back with me Nick. I pulled the transmission yesterday and the pan was clean. I had it rebuilt about 5 years ago and it always has a whining sound to it after that. Transmission shop said it was ok. Whining sound is gone now and I'm having this problem.
Great video again. Question tear down and inspection I found my direct drum race intermediate clutch is worn down. I have a TH400 one can I use it on the 4l80e direct drum? I noticed that the 4l80e top of race is different and had 4 slots cut in where clutches ride. If you advise Thanks Dave.
Hi Dave, thank you for watching...Replace your outer sprag race with a new or good used one, don't use the TH400 race as it's not tall enough to accommodate the 4L80E intermediate clutch pack.
@@nickstransmissions Thanks again, I might ask some more questions. Your Videos are to me the best out there and very detailed. Dave.
Hi Nick, Can you advise. My 4l80E in my 1993 GMC Suburban was working fine, then started only shifting into 1 and 2 gears no third or 4th gears. I did ohm check all electronic and put in all new electronic A/B shift solenoid I have yet to try it out. I read the 2 3 shift valve has a o ring that leaks goes flat. What do you suggest. Thanks
Hi David...Didn't see this for some reason...
Does the transmission stay stuck in 2nd gear and never upshift or does it upshift and feel like it's in neutral?
If the latter, your direct clutch may be failing as it's only 'single-fed' from the factory when in 3rd gear but dual-fed when in reverse...So if the friction material has worn down significantly, that feed configuration could make the difference.
What did the fluid and bottom of the pan look like?
@@nickstransmissions Hi Nick, It was the external harness wiring and computer to trans, It's a 93 GMC Suburban 454 4l80e.
Trans had no junk on bottom of pan when I removed it. So I figured the trans was still good. Watched a video on making the trans run full manual, man it works nice to. What I ended up doing I hard wired a extra external harness and made it run full manual I have to shift it. I know this mod applies full line pressure at all times. I also replaced all the electronics inside trans, and new speed sensors to along with a new filter kit and new oil. Shifting with the column shifter for now I have a floor shifter coming. I also ordered the TransGo 4l80e- 3 shift kit to correct it . Truck is running fine. No leaks at all, I have a pressure gauge will check oil line pressure soon. I not interested in making it full automatic anymore will leave as is. Truck is to old and I like it manual anyway. The 4l80 build is going real smooth thanks to your videos and instructions, without it I don't think it would have been possible. Hats off to you sir. You always answer my questions to Thanks for That. I don't want to be a bother to you so I keep questions light. Dave
Hey Nick, trying to get it touch with you on a possible rebuild.
Hi Scot, shoot me a direct message on Tahoeyukonforum.com or Silveradosierra.com. I have the same user name.
Thank you for watching!
Nick, hi. I took another 4l80e from junkyard. The oil was fine, it didn't smell burnt. I put it on the car to check it out. Everything works fine, only the 4th gear turns on with a strong impact. What could be my problem?
Check the 3-4 feed hole in the plate and 3-4 accumulator piston spring to see if it's broke.
@@nickstransmissions Thank you!
You're welcome, man.
I have a 97 k2500 with a 4L80E. The truck shifts through all the gears in the morning or when it has sat for awhile. After about a mile or two of driving it reverts back to 2nd gear. After that all I have is 1st and 2nd gear. Is this an electrical issue or is this a rebuild the transmission issue? Thank you
Sounds like an electrical issue but to be sure, plug in your bidirectional scan tool and take it for a drive with transmission live data pulled up (also engine sensor data). Something seems to be shorting out as the powertrain approaches operating temp. The scan tool should help you determine what that something is. Codes may be stored as well.
Check fluid level when it's hot to make sure it has the correct amt, if you havent already done so. At this point id suspect all things that impact the trans, including the PCM to the trans electrical components and everything in between then start eliminating stuff until you find the culprit(s). Let me know what you find.
I have a vid on testing solenoids, etc on 4L80Es as well - may be helpful for you: m.ua-cam.com/video/J9-Vvdrw78c/v-deo.html
Thanks for watching, Shawn!
@@nickstransmissions thanks a ton, ill be watching you video on solenoids!
@Shawn-fn7vx did you get it figured out? My truck is doing the same thing, but I'm also losing reverse.
Hi Truman, ill let Shawn respond with a follow up but if you're losing reverse, the problem may be either a worn low-reverse piston machine-cut seal or leaking cover plate-to-case gasket. Both can be easily checked and, if need be, replaced by dropping the pan then removing the 6 10mm bolts holding the domed cover onto the case...If you remove the piston and the seal feels hardened/brittle then that's the problem. If not (i.e. it feels normal) than the problem is either the l/r band (minimal friction material remaining) or possibly direct clutch (that clutch is on in reverse as well).