4l80 manual valvebody No OD and third gear in fourth position

[Jaeden de boer]

Couldn’t find anything anywhere else, the issue I’m have is no OD and third gear engages in the OD position (all the way back on B&M pro ratchet shifter)in my reverse pattern manual valvebody 4l80. I’ve had the valvebody off and the fourth clutch engages with air, no gasket between valvebody and trans(running a gasket caused a no reverse issue). The transmission shifts one - two perfectly, then two- three, except that I have to pull the shifter into the fourth position for third. I verified shifter adjustment and it is spot on, can remove the cable in all positions. Valvebody is a TCI 274501. If anyone has any ideas I’m open to anything, thanks.

 

[1998_K1500_Sub]

the fourth clutch engages with air ... running a gasket caused a no reverse issue. I verified shifter adjustment. Valvebody is a TCI 274501.

What are the TCI tech support guys telling you? That's an $800+ valve body, I would expect them to spend a few minutes with you on the phone.

I assume they still have tech support, although I haven't called them since 1995 when one of their 700R4s failed for me.

Here are my stupid questions:

Is their manual valve controlled by a manual shaft, and is that shaft indexed into specific positions by a detent cam?

Have you confirmed the manual valve is indeed in the proper position for each of the positions 1,2,3&4 of the manual shaft?

Is the manual shaft moving in lockstep with the cable, and is the cable moving in lockstep with the shifter, and is the manual shaft position exactly as it should be for each of 1,2,3&4 when the shifter is in the corresponding position?

Do all other functions work as expected (trans brake, TCC lockup)?

What's this about "running a gasket caused a no reverse issue"? Why is this happening, are you using the wrong gasket, or... is there a valve body incompatibility, or... what?

If these questions sound too stupid, just ignore me. But you really didn't provide much background information so I'll start with the obvious.

 

[Jaeden de boer]

What are the TCI tech support guys telling you? That's an $800+ valve body, I would expect them to spend a few minutes with you on the phone.

I assume they still have tech support, although I haven't called them since 1995 when one of their 700R4s failed for me.

Here are my stupid questions:

Is their manual valve controlled by a manual shaft, and is that shaft indexed into specific positions by a detent cam?

Have you confirmed the manual valve is indeed in the proper position for each of the positions 1,2,3&4 of the manual shaft?

Is the manual shaft moving in lockstep with the cable, and is the cable moving in lockstep with the shifter, and is the manual shaft position exactly as it should be for each of 1,2,3&4 when the shifter is in the corresponding position?

Do all other functions work as expected (trans brake, TCC lockup)?

What's this about "running a gasket caused a no reverse issue"? Why is this happening, are you using the wrong gasket, or... is there a valve body incompatibility, or... what?

If these questions sound too stupid, just ignore me. But you really didn't provide much background information so I'll start with the obvious.

I have called tci, and they said it could only be the linkage, as for the gasket, I installed a stock one, it was blocking oil ports(this valvebody does not need a gasket according to tech support). All other functions work, tcc and trans break, when the shifter is in first, the transmission shaft is in the first gear detent, the same for each gear and position. Would TCI have specs for where the valve should be in each postion. Thank

 

[stutaeng]

Was the transmission shifting fine before? If so, it can only be the valve body if that's the only thing you changed. Correct?

 

[Jaeden de boer]

I rebuilt the transmission, it just lost reverse as I was backing out of the shop aswell, I decided to put a stock valvebody back on to see if anything changed, same issues, shifts 1-2 then 2-3(but shift has to be moved to fourth gear position). checked shifter adjustment again it’s in the detent for each gear.

 

[tayto]

did you check the low/reverse servo pin travel?