Friend has a 05 tahoe, 5.3 with 72k on it 100% stone stock.. Just out of no where yesterday he says it will not shift out of 2nd.. Today, i go take a look. Fluid is fine, not burnt. I take the truck for a ride, manual shift the trans, will not shift out of 2nd. I then repeat this with the to haul on, it went into 3rd 3-4 times. After trying to get it to do it again and it would not.. What could it be?? When it did shift into 3rd, then OD it was fine, no slipping or noises.. So if this has happened to ya or you heard of this, drop a line in here.. I have a few ideas, but not sure what to go with :/

 

ive heard something about a transmission safe mode but from what i hear about that it stays in one gear and WILL NOT shift at all so it doesnt sound like thats his problem... other than that i dont have a clue but g/l with it. if it comes down to it and he needs a replacement my stock 65e is up for sale! only 25-30k miles on it since it had a fresh rebuild when i bought it.

 

Does it start out in second? Can you force it into gear with efilive/hptuners? The torque converter ever lockup?

 

limp mode is 3rd gear i believe.

 

No it starts just like it would on a reg operating trans, but will not shift out of 2nd gear when the lever is in D.. But like I said manually shifting it, with the tow haul on it would go to 3rd, to 4th some times. But then stopped. As far as hooking up, I do not have the stuff to do that so no I can't. Yes it feels the TC is locking as it should. Everything feels 100% fine when starting out, just no go after second...

So you are saying it is in limp mode>??

 

Are you sure you get 4th sometimes? I think it might be a bad 1-2 Shift Solenoid

 

Yes I am pretty sure it made it to 4th one time.. So from a stop, 1st would shift fine, then shift to second fine, then it would just stay in second. Only when I used the tow haul button did it go into 3rd, almost sure 4th 1 time..

 

Ah. Different problem then. Weird problem man.

 

I guess I am going try and drain the fluid, put a new filter in.. I can only think that dirt might be stuck in someplace.. But i am not a trany guy, so the rest is left to my imagination...

 

While your in there, swap the shift solenoids around. they are the same part. Be careful, one is under slight spring tension.