yager

Hey all, first so glad i found this site, TONS of great technical info.. I've been searching for info on my problem and tired of 'whats and HD2 kit'

Anyway.. Local guy rebuilt the trans. Honestly I think it was his first 4L80e, he's done other th350,th400s, C6s etc, so I don't think there's any issues with the basic rebuild.. The trans has been working great, just back from a 1200 mile trip to NY and back..

The only issue is ZERO engine braking in Manual 2.. All forward gears seem to work fine, and the shift kit is super and shifts (slams) all the gear pretty hard..

Symptoms..
I can run Manual 1st and it will engine brake as expected (obviously its not a stick and engine braking has limits)

In Manual 2nd, I can run the engine up to say 3500rpm and when i let off the gas, its as if i put it in N and am not coasting. If I hit the gas hard to where I was before, it will pickup and re-accelerate.

Similarly when I manually downshift from 3rd into 2nd, its as if i put it in N. But if i hit the gas to make the engine match the tranny speed, it will engage and accelerate me. But will release as described above...

(also don't know if its even a problem or part of the shift kit etc, but when I shift into R it takes ~1-1.5 full seconds for it to actually engage and move the truck )

Tranny guy is being cool and working with me on this. It was an on the side rebuild that I dropped off at his house. I'm not faulting him at this point because I really don't know what the problem is.. Obviously its not a full time place so I just can't drop the truck back off..

Truck is a 1995 c2500 that has 370k, trans has been out before and was working fine previously, the milage was unknown and I tow/drive several long distance trips and tow ~8k. The full rebuild included new converter, all 4 new electronic solenoids, (A,B,TCC,FA) and new internal harness and the HD2 shift kit..

I'm capable of dropping the pan and VB to look at stuff and fix anything that may be needed. (honestly if I had found the rebuild write-up I would have had the confidence to do it myself ) I have a feeling it may be obvious when I open it up..

Where should I start and what should I check first ? Tranny guy thinks maybe one of the 'plugs' that the kit has you install in the separator plate may have popped out ? But hes attempting to contact transgo to assistance.. I just want it fixed. As i tow and really need manual 2 to work properly..

Thanks !!!
-mike

yager

tranny guy is an idiot... I dropped the valve body and solved the problem myself.. thanks for the help.

blown3qtr

What was the culprit?

James B.

iTrader: (1)

The 4L80-E HD-2 kit includes a spacer that goes on the apply pin for the front band. I'm going to guess he put the spacer on the wrong side of the piston?

yager

note: if it remotely sounds like i know anything about the trans, its pure coincidence im mierly learning as I go... There were a few minor probably unrelated issues and the main issue.. but all point to pure sloppyness of the install.. first the seperator plate had surface rust, obviously was cleaned then left sitting out, was also dented pretty good from the check *****, he should have gotten a new one. (I gave him the go to do what he needed to, not 'just slap it together'. The 3rd/4th accumulator gasket was half stuffed in the hole when assembled.

The small spacer was on the correct side of the piston... I'm guessing the spring being there would have made it not matter anyway.. BUT the piston seemed a little loose. After looking at it more the piston/seal was not making hardly any contact to the bore, and could not possibly hold any pressure. 1 layer of heavy bond copier paper, made the old piston fit like the new one does... Not sure that that adds up to... but...

The piston doesn't have a number on it so I have no way of knowing if its even correct, it measures 1.75" OD. The case bore ID is ~1.80" The trans 2nd gear did work before the rebuild, so I'm not sure what the teflon seal spec is but its possible he didn't replace the seal at all, used a different part ? etc.. dono... (keep reading)

I 'fixed' it with a sonnix 2nd gear servo sleeve kit. Basically its a o-ringed insert and smaller diameter piston. The new piston fits and moves as i'd expect one to.. (Sonnix also makes a thinner TH400/4L80e sleeve kit that is thinner and gets lock-tighted in also with a smaller piston, similar to a cylinder liner) that got me thinking that possibly idiot removed the sleeve and just wadded it all back together.. Regardless the new 'kit' I have in there now will work..

I'm still waiting on a used valve body to install the new/revised Trangso HD2 kit.. Transgo really took care of me. I called simply wanting to purchase some gaskets that came with the kit, explaining the installer F'd it up etc.. They wouldn't let me buy them, insisting they send me a complete NEW kit.. I just paid shipping.. I was shocked to say the least... (that stuff never happens to me)

But all this said, I regret I didn't do it myself, I've got many other $$ tools to do other various tasks, so a few trans tools wouldn't be a big deal.. The write ups here are super..

blown3qtr

Sounds like you got it figured out. I always like to read "the rest of the story" often threads are never updated with the "fix". that being said I have a couple i need to update.