Transmission fears
 

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?

that does not sound like the b2 issues I have seen.

#1.

Check Fluid Level

I'm guessing you are not bringing me your car to swap the seats into it... at least until you get the transmission issues sorted!

Try changing your fluid and filter.

Is the parking brake on?

Fluid is just under bottom mark with car sitting over night. Parking brake is off. Filter is probably at 40,000. Family has owned since new & PO didn't turn wrench but always had maint done. I'm guessing that trans is original with approx 240,000 mi. I'll ask.

Vstech, I'm not sure when we're coming or what I'll be driving.

... under the bottom mark?
transmission fluid needs to be checked with the car idling on a level surface and it's best if the fluid is at operating temp.
under the bottom mark sounds VERY low.