CherokeeLarado

I bought a Jeep GC with 42RE trans. I know nothing about the maintenance history of the vehicle. I want to service the transmission but have a question on which trans fluid I should run. Should I simply do a pan drop or complete system flush?

93 Jeep Grand Cherokee ZJ

Never do a system flush. Try to reuse your old fluid if possible by straining it with some woman's nylons or whatever. Then top it off with ATF+4. Of course you will change your filter also.If the old fluid is really dark or smells burnt then I would dump it from the pan only (get rid of it) but just don't flush it!!! Replace that amount you dumped with that good Ole ATF+4. Check levels at the normal procedures then after.

Bikley

Yep, ATF 4+ and don't flush.

Something I always do with a new to me vehicle is when I pull the pan for a filter change, I replace the pan with one with a built in drain plug. They are cheap ($35 on Amazon) and save a lot of mess and hassle down the road.