Hello to all
this is my first time in the forums. I just purchased a 1998 gtp with 130k. has some aftermarket parts like a dhp pcm. it went to the dealer right before i bought it with a surging problem at hyway speeds.

this is their report
codes p1811,p0137 found coil and wire corroded causing missfire on accel and tcc pressure solenoid is failing.. replaced solenoids repaired wire installed exhaust springs on collectors replaced rear main seal and pan gasket. test drove after repairs ok now

total price 1387.00 end of report
seller drove it 20 miles and parked it because the tranny was slipping. i bought it knowing all this and knowing that i may have to replace the tranny


now transmission is shifting very funny. goes in and out of lockup at random times. slipps sometimes.

took it to the tranny shop. they claim they put 5 quarts of fluid in and said the tranny is junk.

it now throws a p0742 code

any thoughts?