DTC P0757 = Tranny Fubar'ed :(

[GeddyLee]

My tranny has been acting flakey for the past few weeks and tonight it went nuts The shifting is ALL jacked up now. Here is what I found out about the P0757 error code. The information came from a LS1 GTO forum, but it explains my problems to a T! Now I have to figure out what needs to be done to correct the problem.

Oh Dave...................................

Check the TSB's: LS1GTO.com Forums - Open track day 5
DTC P0757 Set, SES Lamp Illuminated, Poor Performance of Transmission, Transmission Slipping (Clean Transmission Valve Body and Case Oil Passages of Debris) #01-07-30-038B - (Jan 26, 2004)
DTC P0757 Set, SES Lamp Illuminated, Poor Performance of Transmission, Transmission Slipping (Clean Transmission Valve Body and Case Oil Passages of Debris)

with 4L60-E/4L65-E Automatic Transmission (RPOs M30/M32)

Condition
Some customers may comment on any of the following conditions:

The SES lamp is illuminated.
No 3rd and 4th gear.
The transmission does not shift correctly.
The transmission feels like it shifts to Neutral or a loss of drive occurs.
The vehicle free wheels above 48 km/h (30 mph). High RPM needed to overcome the free wheeling.

Cause
The most likely cause is chips or debris plugging the bleed orifice of the 2-3 shift solenoid. This will cause the transmission to stay in 2nd gear when 3rd gear is commanded and return to 1st gear when 4th gear is commanded.

DTC P0757 may also be set if the 2-3 shift valve or 2-3 shuttle valve were stuck, restricted and/or hung-up in its bore.

Correction
Inspect / Clean the 2-3 shift valve, the 2-3 shuttle valve and the valve bore of debris / metal chips.
Inspect / Clean the 2-3 shift solenoid opening of debris / metal chips. While inspecting the 2-3 shift solenoid, look for a screen over the solenoid opening. If the solenoid DOES NOT have a screen, replace the solenoid with P/N 10478131 that does have a screen over the solenoid opening.
Refer to the appropriate Service Manual for additional diagnostic information and service procedures.

Parts Information
Part Number
Description
Qty

10478131
Valve, 2-3 Shift Solenoid
1

Parts are currently available from GMSPO.

[torq455]

P0757 Shift Solenoid B Stuck On.

[Trannyman95]

Sorry to hear James but now you have something solid going on. GM had a TSB on this a few years ago and basically said to pull the valve body and clean it but that wasnt a guaranteed fix either and was just what the bulletin said to do unless there were damaged or severly worn or scratched valves which I doubt. A stuck 2-3 shift valve will cause this but something caused the valve to stick and that something had to come from somewhere inside. A small amount of debris in the trans is common to see but for there to be enough to make a shift valve become stuck it would cause other valves to have issues before as the shift valves have pretty stout springs on them and Im not sure I have ever seen one stuck in these transmissions. Does the car feel like it is starting in the wrong gear? Does it shift through all of the gears? Is it worse hot or cold? If you clear the code will it come right back-if the trans is acting up all the time it should. Are you still using the SLP pcm in the car?

[GeddyLee]

Well I just walked home from Allen Transmitions Shop. Nice little 2+ mile walk back home. I offically now have no 3rd or 4th gear. So my options now are limited. Its not streetable at all. I almost got rear ended twice just driving down Tesson Ferry to look for any tranny shops that could look over the problem and see if they could provide a bandaid fix till maybe Dave could come up with something.

I figure if it is gonna cost me more than $600 to fix, I am just gonna hafta hold off, till I can save the rest of the money up to get a Tranny from Dave or something. Its just soooooooooo disheartening And I spoke with Dave today about what happened, and now its just a wait and see what can be done with the transmition here locally to at least get it back on the road safely.

I guess the only good thing is that my roommate is gonna let me drive her car to work and stuff in the midterm.

[98SilvermistGTP]

You could drop the pan and see what you got going on in there and in the filter. If it is not to bad, as in nothing more than the normal amount of residual clutch material, you may be able to have the trans shop take the valve body out and change the solenoids, and maybe check out a few things that can be checked out with just the side cover off. Of all the trans people I talked to about mine, they all said the shift solenoids are very rare to go out if ever. But, it is not impossible that one could have just gone bad on its own. It sucks but you are probably on the path to a rebuild....I know how I felt when I saw the pile of clutch material inside my filter. But look at as how good of a trans you will have after a rebuild.

[GeddyLee]

Well the guys at Allen called me on Friday afternoon and told me that the tranny pump was on its last leg and thus the cause of my current issue. They have to pull the tranny and replace that at least. I talked to Rob, the guy who seems to know our trannys "almost" as good as Trannyman told me they were going to inspect the rest of it and see what other problems might be hidden in it.

I know from when I had my tranny flushed a little over 2 months ago and see how black it was, it was obvious the previous owner, just beat the ever living tar out of it. And smelling the tranny fluid, you could smell the burn in the fluid before the flush. I smelt that back in May of last year when the TCC silenoid went out in the same tranny. So basically this tranny has been a ticking timebomb for quite some time now.

But over on the St. Louis Club GP site one of our guys told me at least two people had recommended the Tranny shop where my car is currently at and named the one tech, Rob, by name as the go to guy. I went to the shop today and spoke with another mechanic there and asked him if he thought Rob would mind if I looked in on the progress and hopefully take a few pictures of the damage etc. He said he didnt see a reason why not.

So I am feeling pretty confident, but only time will tell what will happen after the repairs are all done and my GTX is back on the road

[GeddyLee]

Here are some pictures I took today of the "soft parts" of my tranny after they were removed. Sorry for the not so fantastic quality of them, but it was only 20 degrees in the garage and my hands were shakin pretty good. But in most of the pictures you can see scoring and burn marks on most of the pieces.

















I will try and get some of other parts that showed significant wear on them later on.

[Trannyman95]

Holy crap James! That is pretty bad, especially since you have a TH400 roller clutch element in one pic!!! LOL They must have thrown in something that should be there. Those clutches are toast though, sorry to see it was that bad inside.