Transmission needs to be reprogrammed?

[shadowless127]

Trans operation with overdrive on (regardless of what gear) flat out sucks. If I turn O/D off, trans operation is 100x better.

What's the deal?

 

[shadowless127]

anyone?

 

[jrford]

What RPM's are you running. . .mph? can you expand on the symptoms?

i have the same thing you do. . . .2000rpm's - 70mph.

 

[shadowless127]

I get soft/hesitation on shifts, the tranny bucks on occasion randomly on launchs and while cruising (when cruising its usually around 2000rpm's).

If I turn O/D off, I get nice firm crisp shifts, and absolutely no bucking.

It almost seems like the computer has some "corruption" when the O/D Program/profile in on, but when it switches to just 4spd (non-O/D mode) it runs flawlessly.

 

[jrford]

This is a tough one,. . .
With the 5spd you know that overdrive has a planetary and sun gear. Without O/D and in 4th gear there are no gears involved power is put straight through transmission to the diffs, transmission does nothing in 4th, 5th O/D the clutches are activated and now the engine spins 80% less than 4th.

I'm only guessing but it sounds like the O/D is toast. At this point if it where me and my truck was doing that.. . .id pay the $90 for a diagnosis from the stealer to confirm that there is a Hardware failure or see if any codes are being posted. . .or maybe they could reflash it for you since they are billing you for the hour. You might start by asking if there are any updates for your VIN/year . . .honestly it doesn't sound like an easy fix, i doubt there is any corruption in the PCM, there are usually software checks to make sure the code is written correctly, and if there was i bet it would put itself in fail safe mode if it suspected something wrong. .. .

 

[shadowless127]

This is a tough one,. . .
With the 5spd you know that overdrive has a planetary and sun gear. Without O/D and in 4th gear there are no gears involved power is put straight through transmission to the diffs, transmission does nothing in 4th, 5th O/D the clutches are activated and now the engine spins 80% less than 4th.

I'm only guessing but it sounds like the O/D is toast. At this point if it where me and my truck was doing that.. . .id pay the $90 for a diagnosis from the stealer to confirm that there is a Hardware failure or see if any codes are being posted. . .or maybe they could reflash it for you since they are billing you for the hour. You might start by asking if there are any updates for your VIN/year . . .honestly it doesn't sound like an easy fix, i doubt there is any corruption in the PCM, there are usually software checks to make sure the code is written correctly, and if there was i bet it would put itself in fail safe mode if it suspected something wrong. .. .

the thing is it doesnt just happen in 5th gear; thats what has me boggled

 

[High_Order1]

i bet it would put itself in fail safe mode if it suspected something wrong. .. .

e-quizzer. It doesn't like ANY parameter - the wrench light comes on, codes are written, and it goes into limp-home mode.

JRford - that was a great answer, by the way.


Totally clueless here... but, since it can be made to fail and not fail with a button push, could it be something electromechanical, like in the solenoid pack? From reading, I see its' a common point of failure, and potentially, it could be failing without an associated code.

-Shawn

 

[shadowless127]

e-quizzer. It doesn't like ANY parameter - the wrench light comes on, codes are written, and it goes into limp-home mode.

JRford - that was a great answer, by the way.


Totally clueless here... but, since it can be made to fail and not fail with a button push, could it be something electromechanical, like in the solenoid pack? From reading, I see its' a common point of failure, and potentially, it could be failing without an associated code.

-Shawn

That's what I thought, but the solenoid pack was changed 23K ago (last year). Could it go again that quickly?

 

[High_Order1]

I think, with the associated failure rate, it's possible. Or, maybe it was installed incorrectly, or the seperator plate bonding material has now started coming loose, and as long as certain paths aren't pressurized, its' ok?

The smart people all say that psi is the key. search 5r55 on here, for what kind of gauge and how to install it temporarily to see if those numbers at each place in the shifting strategy helps someone else help you figure it out.

-Shawn