So I picked up a 1993 Dakota as a parts car for my 1957 truck project
, The a500 trans works fine but as long as it is out, What should I do to freshen it up? I will be putting new fluid and filter for sure. Any other ideas to keep it running well?

Filter and fluid should be all that is necessary. It's essentially a 904 with an overdrive compounder hanging off the back.

I would add to adjust the bands while you have the pan off, tighten up the line pressure screw a couple turns (the spring loses a little tension over the years)and use type-F fluid. There are some other respected trans guys who say no to the type-f but my experience says use it.

Thanks Guys

Only time I ever tried type F was after taking a running 727 down for a band adjustment, fluid and filter change. Next day all the friction material came off my clutches. So I wouldn't use it myself, except maybe on a fresh rebuild with new friction material.

If your 500 is a lockup clutch one then expect some shudder when not using the specified fluid as well.

I'd tear it down and get it out of the way for some years. Changing fluid and such won't fix an older unit with dead seals etc. IF you have used this unit and happy with it,run it.

Type F fluid is inappropriate for any OD transmission.

John is one of the guys who knows more than me about these trannys.

John I just almost never see OD bearing/gear problems here, maybe because it is way cooler than where you live? Mostly clutch and band failure

Classic case of doing it wrong and getting away with it versus doing it right.

OD transmissions need the lubricating properties of the fluid that's designed for them....Type F has the least lubricating properties of them all.

So what is the best type fluid to run in a 500 or 518 trans? ATF+ or Dexron ?

I think the early ones call for dexron and by the end they were calling for mopar +4.