history of the car... 1985 Chevy Monte Carlo 4.3l v6 vin Z 4spd overdrive transmission..well i got the car about 2 months ago..its been sitting for 5 yrs.. i replaced the fuel pump got it running but not running good replaced a fuel injector still running bad replaced the cylinder head found a hole in the inside from a coolant passage to the valve..at first it would down shift and shut off i changed the trans fluid and trans filter it doesnt shut off at a stop hard or soft doesnt, matter.
also when accelerating it shifts funny and if i let off the gas it feels like it doesnt downshift to good too but when i took back n fourth from maryland to pittsburgh it does fine cruising at 70 to 75 all the way there non stop not even for gas.

Could it be something with the valve body and no i didnt think to check the valve body when i dropped the pan and filter.

 

The valves in the valve body could be sticky from sitting all those years. Have you tried manually shifting it to see if it works any better?

You might want to take it to a reputable local independent transmission shop and have them look at it. The good ones will take it for a test drive and can almost tell exactly what is wrong with it. Dont take it to a chain shop like aamco.

 

Thanks ill try manually shifting later on today and would the same problem happen in the gear that seems to be missing im guessing it would?! But yeah ive been telling my self to take it, to atleast see what the problem is but im pretty broke right now so it wont be anytime soon..but thanks for replying after like 15 views :/ and not 1 reply other than you