My Olds 2001 Aurora 3.5 has hard shifting (jerk)from 1st to 2nd on accel and decel. The only times I have noticed it is when I have been on the highway for a long time. Pulling into a parking lot after getting off the highway is ok, but when the engine is turned back on the problem starts. The next day its fine.
This has happened three times after long trips (interstate driving). After 2 hours, I stop for food and its ok. After another 2 hours (when I get home) is when it starts. During the last 2 hours, there are many hills, but very rarely downshifts.
85,000 miles, the transmision was worked on in 2007 at 65,000 miles.
I can’t quite track with the longer trip length. I would think the trans would be at normalized temps long before 2 hours, and that’s about the only component that would occur over a longer duration. On the interstate it’s not shifting at all. This is the last place I’d expect a thermal issue to be present.
I’d do an Auto-Rx transmission treatment and exchange the fluid. That will assure that anything fouled, including the cooler circuit, is cleaned out.
Had the same thing happen on a 2004 Dodge Neon. Took it to the tranny shop and they hooked it up to their equipment and found that a connector on the transmission was corroded. They cleaned the connector and reset the transmission module and now it runs and shifts great!