My 85SD has been parked waiting on other projects to be finished so I could address climate control and transmission issues. Today, I decided to drive around the block.

Pressed the accelerator, engine revved, tach went to 3500, car barely moved. At 4000 car shifted up then back down then continued to shift up & down 1 gear only with only small changes in the accelerator.

Is this only a B2 & spring &/or vacuum problem or is there something more serious that will require pulling the trans?. How do I diagnose for sure?

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85SD 240K & stopped counting painted, putting bac together. 84SD 180,000. sold to a neighbor and member here but I forget his handle. The 84 is much improved from when I had it. 85TD beginning to repair to DD status. Lots of stuff to do.