I had my Carnival in for regular maintenance and had the A/T oil replaced. But instead of Dexron II I bought Delco Dexron III and that's when the reverse problem started.

The car reverses fine when the ground is level or near level but when it has to go over an obstacle or a ramp from dead stop (no momentum) the transmission judders big time. At one point I rev'ed the engine to almost 3000 rpm (with the transmission juddering all the while) when it lost power and the revs went down quickly.

Is this due to wrong type of ATF?