4L80E Stock rebuild

Jun 25, 2022
Lexington SC
My 4l80 project is complete and is a success and much thanks to Clinebarger on this very site . Mine is a totally stock built unit ,It is very smooth and quiet and I made no changes to the stock Transgo single separator plate though I will enlarge the shift holes to about .085 the next time I do another. It shifts so smoothly you can't really feel it shifting and reminds me of when it was new.

I did not do the direct feed modifications because of a few thoughts that repeated in my head:

1---I don't want to wait on reverse as I am stuck in traffic on a railroad track and hear a train horn--LOL
2-- This is a stock work truck with a stock 6.0 engine equipped with a tow/haul button
3-- The heavy return springs in the flimsy direct stock cage can warp and have been known to come apart although rarely in a stock application but still
4-- My stock 4l80e lasted over 200,000 miles before rebuild
5--Lastly, GM never made the modification in all the years it was produced 1991-2007

Tell you what I do believe in strongly and that is center support cup seals included in the cheaper Transgo shift kits( Never use their relief valve) or purchased from a trans. supplier part 54386A--I used them to the left and right of the center support bolt and tapped them in with a 5/16 round punch,Rubber touching the support. Some have made a statement that they don't really matter --Really? We are trying to save as much leakage as possible. Look at the gap next time you drop the support in and see.Yes the bolt pulls up tight but there is a slight gap on the left & right feed holes--Seal them!
I also recommend hand sanding the reaction carrier with 400 to 600 grit 2 passes wet with fluid to de-glaze it for the new band and spray it or rinse it clean with solvent.For the band apply pin there is a video by Jake and a simple band/pin test just google-- Transgo #06-178-- Take your Servo apart and you will know if you're in the ballpark.Do this right after you lower the carrier in the band -If the reaction carrier is not overly worn and you have your original pin and servo assembly and it looks and measures as it is pictured you will be good.Another watch out for item are ALL servo seals and this tricked me the 1st time. Match them carefully and Hand test the fit with each seal and piston ,with fluid, to make sure they have some resistance.
Valve body-- I originally purchased the Transgo ACL valve kit and while it is a good deal here is what I will do going forward. I will pull and inspect all valves and bores and decide right then and I do mean pull all parts in the valve body .The 3-4 reverse check ball assembly was slightly worn on mine.I replaced everything I thought even might be an issue . When you add it all up I should have bought a Sonnax remanufactured valve body with all new electronics and a lifetime warranty. I may have saved money if I had
Every bushing and every seal is so important I can't believe it.My center support purchased from a reputable rebuilder and listed as Drop in and go---dropped out period!! The center support rubber piston seals were so hard they spewed fluid under the slightest test pressure , replace them all.
Converter---Reman at the very least
Pump-- A straight edge and common sense measurements should answer this but I'll let that be your choice -Certainly get a new boost valve assy. and bushings and also drill a line to lube hole.
Internal harness--Get a Rostra 40 buck new one and you won't have to even guess
Rebuild kits--Tough one--I like the Transtec rubber and the Borg clutches and steels and Raybestos

A few things that do confuse me were mainly ATSG who are cheap A**H*LES .They make some real money and offer confusion as designed.Take the 4l80 valve body reassembly pages.My manual is a 2003 with updates.It literally states drop in all valve body body bolts and torque to 116 inch pounds.Now turn to the torque specs page and it reads 97 inch pounds. I have lost respect for them. BTW-Mine were torqued to 116 in lbs.& works great-And another thing,Can ATSG afford an out of work newspaper artist/editor or meth addict to write for their technical manuals going forward? There were better drawings in the 1960's kids search a word and maze magazines,Even comic books were clearer ! How much did you pay for your ATSG manual again?

Another confusion is everyone yelling rollerize everything- After 200k my thrust washers/spacers looked great.I can dig it for 1000hp race cars but hey! Unnecessary for a stock vehicle.

This last part is strictly my opinion only--If I took everyone's opinion on improvements for the 4l80e and performed them--It would never even pull out of the shop. If you start drilling holes in any hydraulic system with a single pump you will gradually lower fluid pressures somewhere else unless you block other stuff shut. If a hydraulic unit like this served you well for many many miles and you are not racing hard--What do you want from it? Another long term of service or brute force until breakage? As Gil said-Thanks for listening

Data given as collected--Vger
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Clinebarger helped me a lot on the rebuild of my th400. Couldnt have done it without him. I had wierd or simple questions that no where online were there answers but he knew. I also decided not to dual feed as i didnt want reverse any slower than it already was. I did rollerize the rear though.
Another confusion is everyone yelling rollerize everything-
I've noticed some of the roller cam guys (Isky for one) have switched from needle bearings to bushings. Now some of this is for a better failure mode, but don't sell bushings short. As our bushing guy at Allison used to say "if it's designed right, they don't wear out, they wear in"
Pitiful --Visit their website at atsg.com and shop those crazy deals!! Allow me a 3 minute speech to the CEO---HEY ATSG !!Get off your #SS and chime in ,We know you are here.
I pay over $400 a month for OE service/repair information & estimating services. ATSG is not going to renew a license to reprint a manual for a unit that hasn't been produced in over 10 years.

I've been rollerizing the Output on TH400's & 4L80E's 2 decades without a known failure.
You are the true victim I am referring to. Shops pay in millions of dollars for substandard care/products. Answer me this clinebarger, Who is ATSG's competition ? Is there another service?

As far as rollerizing, I don't condemn it in race applications,I just feel it is a waste of money and time for stock applications. There is no rollerizing valves,bores and pumps at 150k miles. Simply my opinion.
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ATSG pretty much has the market cornered now days far as printed trans manuals, Long ago......Lincoln Technical Institute printed Factory Service Manual grade overhaul manuals, I have one from 1973 that covers just about all domestic automatic transmissions that were on the road at the time. Really good manual with great drawings!!

I use my subscriptions to access updated Factory Service/Repair Information. Lets say I did need a manual to build a 4L80E.....I would use information for a 2003-2006 year model which is light years ahead of a ATSG using 30 year old photocopied pictures.

I agree with you to a point on ATSG, They print a manual.....Then print a "Update/Supplement" manual for the same unit, Now they get to sell TWO manuals & make twice as much money.

That being said.....Their latest manuals (6L80E, 8L90E for example) are pretty good because the Factory Service Information & drawings were better at the time of printing. The older units (700R4, 200-4R, 4L60E, 4L80E) were a Trash In/Trash Out type of situation.

Far as being a victim.....I don't look at it that way, Service/Repair/Estimating Information is quite cheap in the whole scheme of things when you're running a business!