Hi Everyone, my son and I (6 months ago) completed an engine transmission swap in his Grand Prix. We purchased a complete drop out L67 engine/trans from Morad autoparts when his L36 died.

It has been running fine but yesterday he was pulling out onto the highway and just got up to about 60 MPH when the car shuddered and then acted as if it were in neutral. The fluid level is fine, looks clean, and smells good but the car is failing to engage in any gear and is reading the codes P1810 and P1860.

So far I find that:
Code P1810 TFP (Transmission Fluid Pressure) Valve Position Switch Circuit
- may indicate an electrical problem?

Code P1860 - TCC PMW Solenoid circuit electrical
- would also seem to indicate and electrical failure?

I was able to verify 12 volts on the pink (I think connector E) wire on the trans electrical plug so that seems to be OK.

Since we did the swap I think it is completely possible that we damaged the wiring somehow and I would prefer fixing that to a trans rebuild. I am even game for solenoid replacement if I can determine that is the culprit.

The transmission shop just said we don't know til we tear into it.... translated as $$$$$$

it seems strange to have a sudden catasrophic failure like this to me as prior nothing seemed to be slipping etc but the transmission shop seemed to be leaning that way?
thanks for any assistance you can offer.
Merritt