Engine/Transmission (1994 - 1998) Rear main seal

[SFrey]

getting ready to put my transmission back in my 96 CTD, just wondering if i should put a rear main seal in. It's not leaking now, but i would hate to have a leak down the road. truck has 174,000 miles on it.



thanks, scot

 

[Joe G.]

I would leave it alone. Mine has 242K on it and the rear seal is still working fine.

 

[NHays]

I concur, Leave it alone.

 

[radixr]

Change it.

Mine is leaking slightly (118,000 miles). I'm not going to change it until the transmission comes out for some reason or it starts to leak more. I don't know what a seal costs, but it can't be that much compared to dropping the transmission. It will eventually start to leak.

 

[JSienkowski]

I'm doing mine while everything is out for the clutch, my luck I would get it all back together and it would start leaking, only dropping the stuff once. NAPA has a kit for around 50. 00

 

[CumminsPower98]

I replaced my rear main while I had it apart even though it wasn't leaking. I have a hard time not doing something like that when it involves a lot of work. I did my front when I did the KDP and the interesting thing is that it was leaking at and before 67k when I got the truck but now with the new National brand seal it's still dry as can be at 281k+ and more time on it as well. Same with my rear pinion seal. It was also leaking when I got the truck and it's also still good with way more miles than the OE had. Oh and this is with synthetic oil all around too. Strange...

 

[burnin oil]

From Cummins the

rear main $39

rear main seal adapter (metal housing seal rides in) $41

gasket for adapter $6



If you change the rear seal make sure the crank is perfectly clean. Use brake or electrical contact cleaner to get all residue off the metal and install it dry. The seal transfers a layer of teflon to the crank to prevent a leak.