Need some insight have a 92 d350 has developed a somewhat aggressive oil leak from the bell housing vent. truck has 90k the getrag 5 speed. is the rear main seal something that can be done with the oil pan removed?? what king of seal p/n any info helpful..

 

Gotta pull the tranny. The seal fits over the shaft, is quite expensive, and when I had it replaced on my 89, it had to be installed bone dry. No oil or lube of any kind. The guy that did it couldn't believe it so I copied the page out of the manual and took it to him. Installed it bone dry and never had another problem.

 

part #4429410 List Price: 71.05, but verify the # to be correct.

 

I know I keep harping on about us here in the UK.. .but I have come across the rear seal problem on our 6bt bus engines..
Check the crankshaft end float before doing anything....I have found on a few occasions the crank thrust washer's wear and drop in the oil pan...causing the shaft to move for and aft...
Worth checking...don't want ya putting a seal in to find it leaks in a week or so....

 

I'm with Johnzie on that one. Several guys with 5 speeds in the 1st gen forum have had the thrust bearing fail.