rebuild transmission slipping gears?

Question

my mom owns a 1998 poniac automatic and she got her whole transmission rebuild with new parts. they charged her $900 for the rebuild and 1 yr warranty. its been two times now that she gets the check engine light on and both times the code p1870 appear. searched the code and says the transmission gears are slipping. the mechanic says that the code is rare and finds nothing wrong with the trans.

Any thoughts on what can be wrong im so tired of driving to the mechanic!
thanks!!

Answer 1

1870 code is not rare. It is a slip code and it can go back to a faulty valve body or too much clearance in the clutch packs. External solenoid will not cause this code on this transmission. You have a 4T65E in this car. And no the bands don't sync as someone said earlier. They are also bad about the piston in the forward drum becoming ring cut. Whoever did this job for $900 is a idiot. At $900 all he did was a patch job not a rebuild. If he would use a Transgo shift kit it will probably fix this problem. People like this give the transmission industry a bad name.

Answer 2

did not rebuild it with new parts sorry to say. all he did was replace a couple of clutches and used a kit and charged for that. the code keeps coming up due to the fact he did not repair one of the most common problems with these transmissions so start looking for another transmission shop and get it done right find one at ATRA.COM

Answer 3

check the sensor connector. it could not be connected all the way or faulty sensor. I would also check the fluid level and bands to make sure they are still in synchronized. if they are off sync, they will cause the slipping, same with low fluid. Start with the sensor and connection first, that is easier.

Answer 4

get a new transmission so it wont happen again