What oil should i use for a 1983 5 cyl. diesel with over 300,000 miles on the clock ? it's still running strong. also, the oil is really dirty, should i run some automatic trans fluid (1 qt.) before draining the oil ? Thanks in advance.

 

Any good synthetic rated for diesels will serve you well. The oil will always be black. It's a diesel.

 

Thank You. One more question. What type of automatic trans fluid ? I priced some made for the Mercedes benz cars, $12.95 a liter. Jeesh, what do they think it is ? a Harley Davidson ? I just want to change the fluids, not rebuild it.