I just purchased a very high mileage 2000 Dodge 3500 with a five speed transmission. A lot of mechanical stuff had been done to it recently (fuel pump, clutch, and transmission) and I felt safe buying it since the truck is in overall very good shape. Now I have found out about the block 53 issue, which this one has. Where does the crack usually occur? The only other troublesome issue is a leak from the front seal on the transmission. Is this a difficult fix or costly fix? As an aside, the fuel mileage is somewhat lower than expected, that is about 15 mpg with mostly around town driving with some interstate towing an open trailer with two motorcycles weighing about 1100lbs.

Should I just run it thru another auction and buy a later model, if so which one?

 

What is high miles? 2 trucks in my family with over 350,000 and no crack. Passenger side of block at the rear near the last 2 freeze plug's.

 

High miles in this case is about 300,000. The truck is a tow vehicle (permanent 5th wheel and goose neck ball) so its life has not been an easy one. It has a 3.55 gear and the five speed with a leaky front seal. Is it easy to change once the trans is out.

 

Your mileage seems reasonable for a 3500. You could try resetting the APPS and also cleaning / replacing the MAP. Do some searching and you may find what others have found work. A simple box like an EZ also seems to have a positive affect on mileage.