1998 3.4 and a340f automatic in my '95 4Runner. I can crank the auto trans lever down into 1st, but it will shift out just like normal. Won't hold in 1st or 2nd. O/D lockout works. Any ideas?

 

Transmission threads are always the least popular...

 

could be that the tranny is a goner. Did it come from donor vehicle with S/C? If it did, and the valve-body wasn't upgraded, then most probably the tranny needs to be rebuilt.

 

the one shift in a transmission that is all mechanical, is shift to 1st gear
it is a guarantee...so your problem might actually be very simple

something broke or snapped or a linkage is messed up

 

Thanks for the input. I wired up this swap myself, so another guy in the 3.4 swap section suggested some wiring to look at. After looking over my adapter harness I didn't wire up the L and 2 on the transmission to ECU. It's an electronically controlled transmission and L and 2 have their own positions in the ECU plug at e12-1 and e12-10. The linkage is all good, but apparently it needs ECU input to hold in 1st or 2nd. I'll try to report back, but it's looking electrical, and something I caused.