30TH, 31TH Valve Body

30TH (A404), 31TH (A413, A471, A670) valve bodies come in three different designs. The first one is from 1981 to 1986 non-lock up. The second one is 1987-up lock-up without thermal bypass and the last one from 1999-up lock-up with thermal bypass.

There could be any number of reasons for a valve body to go bad with as many number of symptoms. Two symptoms that I hear of with some frequency is two gears engaging at the same time and transmission taking off on second instead of first. These two symptoms might be a good indicator that a valve body is needed.

From 1987 and up the valve body uses a Lock-Up Solenoid (TCC).