trans problem

[pythus]

98 grand am 2.4 w/ auto(assuming 4t60e)
for as long as i have owned this car(5 yrs) it has shifted hard out of 1st, but recently the shifting has worsened and 2nd-3rd has begun shifting hard. there are no problems on downshifts. also the trans will occasionally stall the car. if the car is cold and i drive slowly to a stop sign, it will stall, unless i put it in n quickly. if i rev the engine in gear after startup it never stalls, but the idle will always be noticeably lower if stopped and in gear, if i shift to n the car will idle normally, as soon as i put it back in gear it idles low again. it never stalls when put in gear after startup or after driving normally for a very short time. I have had an occasional P1870 code

could there be a common problem among all the solenoids that would cause the hard shifting and stalling(assuming the reason for the stall is tcc not disengaging)? could low oil pressure or vacuum cause this?

any help would be greatly appreciated

[GTP Dad]

Welcome to AF!!

There are a couple of possibilities here but let's start with the TCC solenoid. Usually the solenoid will release when the car is shut off and it won't reengage until the car reaches 35-45 in third gear so I doubt that is the problem. The second thing it to make sure the fluid level in the transmission is corrrect. It is difficult on these transmissions but it can be done. If the level is low it can cause issues with shifting. If you haven't had the fluid and filter changed lately you may want to have it done just to make sure you have the proper fluid flow. Just make sure you don't flush the transmission if you have more than 60K miles on the car.

The real possibility here is a problem with the pressure control solenoid. It controls the pressure at which the car shifts. I would take the car to a transmission shop and have them run a scan on the transmission. They will be able to tell you what is wrong very quickly and should it be a solenoid or something internal this is the best way to diagnose it.

Good Luck!!