I am buying a 93 cummins with an auto and was wondering what are some of the weaknesses or flaws these trucks have to them?

The Cummins is a fine motor. The weakness is the automatic tranny. How many miles on the one that you are looking at?

The engine is great, the truck sucks. If only the cummins came in a Ford or Chevy 3/4 to 1 ton truck.

KILLER DOWEL PIN (KDP) look it up. I believe '93 falls into that era.

Most of the first gens don't have the KDP problem, however, its not a bad idea to go ahead and do the fix anyways, its quick and easy.

The auto tranny really isn't too bad in them either, its the A518, which is basically an over drive version of the 727, its heavy duty. It also has a non-locking torq converter, which if you're not careful can cause some extra heat when towing, however; the fact that its non lock up also save alot of extra wear and tear on the tranny that the newer trucks have problems with. The only real weak link in the tranny is the Torq convter, I got a new one from Hughes Performance, and have been really happy.

If its a manual tranny it will be a Getrag 360, I can't tell ya a whole lot about it, other than there are guys running 500+hp through them that are holding up, you just need to over fill them by about a quart.

The first gen forum on www.dieseltruckresource.com is an excellent place to get all the info that you would ever need.