This is a brand new problem. 92 300 te, 148k, trans rebuilt 12k ago. I can feel every shift, but any attempt to accel. will cause immediate slippage in any gear including reverse. It will drive if done very gently. Fluid is clear and correct.
Any diy suggestions greatly appreciated!

 

Well I first looked everything over, made sure there was no obvious external faults, no plugs disconnected etc., then I drained and replaced trans fluid and filter although it was clean and correct level. I finally brought it to a trans shop and they checked pressures and diagnosed it asa band problem and clutch packs slipping, teardown required to further diagnose.
So I am now on the prowl for a known-good used transmission.