Quick question. Does one check the ATF fluid with the engine running or off. The owners manual isn't clear and it makes about a quart difference. Thanks a bunch.

 

Running with the engine hot idling in Park on a level surface.

 

I once had a 1996 Caravan. It had the shudder problem. FLushed the tranny and used ATF+3 and "Lube Guard" sold from NAPA. Lube Guard is widely known to RV'ers who do a good deal of towing trailers. Both Travel Trailers and 5th wheels. The Lube Guard raises the hot flash point so as to prevent the foaming in the tranny and messing with the sensors. This really solved the Chrysler tranny issue for us.