I’m trying to setup my 4l80 clutches and wanted to see if the specs look ok. Had to get creative with the steels to get that endplay. Should I omit both waves, just the direct? I read an alternative is using T400 waves as they are thicker. This is for a 5000lbs van making 700+ with a loose converter.

Direct stack:
No wave, .090”, .090”, friction, .090”, friction, 0.90”, friction, .090”, friction, .090”, friction, top plate =.054” clearance (.065” with wave)

Forward stack:
Wave, .090”, friction, .090”, friction, 0.90”, friction, .077”, friction, .077”, friction, top plate = .033” clearance (I believe these are good having tighter clearance?

Intermediate - .083” seems too loose to me. I believe I can run some T400 intermediate steels to tighten this up?

 

I'll let the expert chime in. But I'm curious what the rest of the vehicle consist of? Engine, axle, etc?

Is this a fun van? Sounds cool.

 

The combo is a pretty built LS with a S475 turbo, 4l80 and just the stock rear end. It’s honestly an absolute blast, and still useful.

 

All looks good except I would open up the fwd a bit as you want minimal drag here due to extended idling and reving in N/P

Keep wave in FWD but none in direct. No wave in FWD makes for nasty apply N-D .

INT as mentioned I would tighten this a little try and get closer to .030 to .040 and retain wave in int , reason for both reduce the speed impact to the case. Also consider a retainer clip on this one from a 727 or from transgo.

 

Thank you. I could swap out another .077” in the FWD, and theoretically net me .046”. What do you typically aim for clearance wise? is the T400 wave recommended?

Is using a T400 intermediate steel the proper way to tighten this up? I will keep the wave, and I already have the thicker snap ring from the transgo kit, although it was very hard to get in, and I had to take time to sand it down to fully seat it.

 

The TH400 wave is fine , I just would never use the dished plate.
The ,046 would be just fine for fwd .050 to .060 is my general goal here but .046 is close enough IMO.
YES THE TH400 STEEL WORKS WELL , I use it at bottom of stack just above wave.
Odd you had issue with the transgo clip never run into that maybe a manufacturing tolerance issue. Note the 727 clips are selective maybe consider a set of those next time.
The 4L80 has considerable travel on the fwd direct drums so clearance is not super critical as long as you have enough,
The INT is a bit more touchy as you want to minimize impact to the case lugs and its important NOT to have the slip ends in the large open area.

 

Thanks. Ordered the t400 wave, are they thicker than the 4l80 forward waves? Wondering how they will impact the stack after swapping in another .077” for some more forward clearance.

Also ordered the T400 intermediate steels, and will put them at the bottom of the stack.

 

Got things together with new parts and the clearances seem to be pretty good.

Direct- No wave = 0.054”
Forward- With T400 wave = 0.045”
Intermediate- Stock wave with 2x thicker T400 steels = 0.034

How do these numbers look? Are the intermediates too tight now? I can remove one of the T400 steels, which should get me to ~0.058”. Aren’t these good to be a bit tighter?

 

Those numbers look good to me, some would loosen the INT but bear in mind they will loosen some when they apply a few times too. I do like to add when not in there additional springs for int release, Some only have like 6 or so I like all the slots to be full if possible, Not required , But yes to me at least those numbers look good.

 

Thank you, I’ll keep assembling. For the INT, I used a heavier T400 retainer to replace the flimsy 4l80 one, and retained all of the stock springs from the old retainer.

Unrelated, but still trying to find out what caused my originally failure, but last time, I installed an accumulator delete plate, but without the gasket (read the wrong instructions since I was using a stock plate…) I assume this could have caused pressure/cross leak issues? After about 200km, it started to jump out of gear and slip, forward clutches were toasted, otherwise the rest looked ok.

 

Be sure to check for groove wear in the forward drum where the rings ride .

 

It looked pretty good to me. Just witness marks, but nothing I could catch with a pick.

 

I can't feel it of course but looks ok. also make sure to change the rings and that the support bushing is good .

 

New bushing were put in and new sealing rings so should be covered there. Also putting in a pump plate since my pump had some scoring (new pump will be used. Just being super careful with the assembly this time around.

 

Double check those rings, I remember years ago a shop bought one to me they had built several times, Each time it would do great for a while then burn the FWD clutch. Spent some time studying it before I solved it, The top ring was smaller top being the one closer to pump on tebh shaft, This was allowing LUBE oil to partially apply the fwd clutch at idle. Not sure if was wrong ring or just miss made but changed it and problem did not happen again and it was not an easy see but I noted it was neary even with the groove in shaft whereas the other stuck out more.These being the larger ones on the shaft. I suspect a 4l60e shaft ring may have been used.

 

thats a good place to air check. put the input shaft into the assembled fwd clutch drum and plug one feed hole with you finger and put 40 psi on the other hole. any leaks become very obvious

 

that’s what I did and everything seems to function as it should. No air leaks that I could notice and the clutch engaged as it should. Seems like it’s coming together and just have to put the pump on and a few other odds and ends before I install.

 

If you use the TH400/early .060 thick wave 34125 in the intermediate you have to also use an early intermediate piston. What year is the core? 97 and up use the black tang wave and the corresponding late int piston. Try to target the tighter int clutch pack clearance as Frank advises. Coan makes a nice billet intermediate pressure plate but you may have to surface grind it a bit to get the needed clearance depending on the thickness of the A727 snap ring used. There’s 3 different sizes with the .106 ring being the thickest and most preferred. There’s also better int spring retainers that aren’t flimsy like the stock one and stiffer springs (TH400) for the intermediate.