Rough Transmission Shift
 

How rough should the shift be from 1-2, 2-3 and 3-4? In the morning I'm afraid of getting whiplash. It's been hot around here so the A/C is running constantly. The shift does get better after he's warmed up a bit. Without the a/c the shift is much smoother, but still noticeable. Another factor is the shift from 3-4. It sometimes feels like a "stutter shift" (for lack of a better term). Kind of like the feel of driving over a couple of concrete seems at about 65 MPH.

One note: the car has 132K on it and didn't have the tranny serviced at 120K like I thought it had (I bought it at 124K). Isn't that service part of the 120K? Would that have anything to do with it?

Thanks in advance for any advice.

Harsh, late shifts are an indication of low vac, and if the problem is worse with the AC on, pull and plug the green vac line in the engine compartment. Make sure you plug the engine side! This will eliminate the climate control as a possible leak. If the tranny shifts properly, you have a leak.

Better, get a MitiVac and test all the vacuum systems -- quite a few posts on this here, you will be able to check them all out quickly.

The softness of the shifts is determined by the vac supplied to the modulator by the white plastic (or aluminum) box on the IP or valve cover -- if you have a leak (very likely at the age of your car), the tranny will shift as though the throttle is wide open -- late and harsh. It will sound as if the rear end is tearing loose -- restore the vac and it works fine!

Peter