Beating a dead horse. Shift valve c stuck

[770JOHNNYW]

I know this has been talked about i have searched all over and thought i got rid of the code. Fresh build no miles. Range shift and throws p0762 i think it is with no other codes. Ive dropped the v.b and without sanding the valve just ran grey scotch Brite in the bore. It wasnt stuck to start with but i did anyway. Help!!!!

 

[onebaddmaxxx]

Don't send the valve period or just throw it away and buy another. The bore is out of round and needs to be straightened..... mikes shift springs will also help prevent it in the future as they are a bit snappier.

 

[770JOHNNYW]

Well just went back out to mess with it again and it shifted out good on the rack. I then went to get fuel on about a 5 mile run did great. Started it back and was in limp again with a stuck B shift valve. I think its got some trash floating around it got a good flush but still has some metal from the toringnton bearing coming apart before the build

 

[rcr1978]

Take it out again and tear it completely apart= take all the springs/valves ect out of it and clean it really good try the old freezer trick= whole valve body in there for a while pull it out thren try sliding the valves in to see if they stick.

 

[onebaddmaxxx]

It's ok on the lift because the trans fluid isn't warm. Once it warms up it will cause issues.

As mentioned. If the valves are free after a few hours in the freezer, it will work in the truck.

 

[770JOHNNYW]

Still haven't figured this one out. It's like it won't learn. The tcm was bad found that out. Swapped it out for one in the yard the truck shifted flawless. I mean like the best I've seen. Had one ever so slight firm 2-1 down shift. I come back reset shift adapts it's back to consistently banging every shift up and down. No limp no codes no nothing. Swapped back to old tcm starts throwing codes. It's consistent with the hard up and downshifting just like it's not learning anything

 

[770JOHNNYW]

Ttt

 

[PureHybrid]

So it was shifting fine, and then you reset the taps? What are you using to reset it?

 

[770JOHNNYW]

So it was shifting fine, and then you reset the taps? What are you using to reset it?

EFI live. It's like when I put a TCM that had the shift adapts already learned it did great. Soon as I reset it they are back to slamming

 

[Mike L.]

If it was shifting fine, why did you reset taps? Resetting taps diverges the shifts. It should only be done once after rebuild. Then it should be driven stop and go for a period of time.

 

[PureHybrid]

EFI live. It's like when I put a TCM that had the shift adapts already learned it did great. Soon as I reset it they are back to slamming

I've never reset any Allison stuff with EFI as I've heard it's unreliable. Have you tried full flashing the file back into the tcm? It's a sure fire way to get the tcm into fast learn. If you're running an early OS that's slow to learn/change and you reset the taps and it doesn't go to fast learn (this is where EFI has trouble IIRC) it might take quite a while to stop acting funny.

 

[770JOHNNYW]

If it was shifting fine, why did you reset taps? Resetting taps diverges the shifts. It should only be done once after rebuild. Then it should be driven stop and go for a period of time.

Stupidity. It had a slight bump I the 2-1 downshift and I have got that out that way. The tcm that shifted good didn't belong to me anyway so I would have been where I'm at anyway eventually.