OK. I've searched high and low, but I've not found anything definitive on this issue, so I'm putting it out there to the braintrust.
My nephew picked up an 03 TB 4wd a few months back, and about 3 weeks ago he came to me with no 3rd or 4th gear.
Inspection up in the pan revealed a LOT of clutch material, and after the fresh filter and fluid and PCS (longshot) he still had no 3rd or 4th, so I took the tranny out for a rebuild.
Now it's all back together and in, and for the most part it's shifting well and firmly through all gears and locking up the TCC and such, BUT...
sometimes it just drops out of 4th down to 2nd and then wants to start off in 2nd and stay in 2nd unless I pull into manual 1st.
I have a PC and software that lets me monitor shift solenoid status and such, and according to the data, the PCM is commanding Shift Solenoid B "ON" and Shift Solenoid A "OFF" all the time unless I pull into manual 1st, at which point both solenoids come "ON" and I get 1st gear.
This is pretty random so far. The truck seems A-OK, and then this happens, and then I might shut off for a minute and it's back to good again.
Right now, the only trouble code is for the cooling fan speed sensor, so I'm going to swap out the clutch module with the one from my truck this afternoon to see if that eliminates the trouble code, and if it does then if it also eliminates the transmission issue.
Does this sound familiar to any of you guys? Or gals?