Rear main seal replace: experienced

[Bluebird]

Advice, warnings, and all precautions that may be needed pursuing the replacement of my rear main seal. Just started leaving a 2" spot since I started driving 'er 1 or 2 days a week. Or, "Let it Be" for a while longer? Truck runs great. Thank you all, for your detailed experiences. Blessings, Patrick

 

[BigPapa]

I would make SURE that the rear seal is actually what's leaking. They're very robust and don't fail often at all.

Oil leaks are generally valve cover gaskets, tappet cover gasket, oil pan gasket, front cover gasket and/or front crank seal, and front gear housing gasket. If it's dripping around the bell housing and rear of the engine, I'd look at valve covers and the tappet cover.

 

[RWherley]

If you commit to replacing the seal there are 2 different ones available from Cummins, the standard one and one with a wear sleeve, get the one with the wear sleeve. I've done multiple of these on industrial 5.9 and 8.3 engines, get some "right stuff" rtv and apply a thin coat of it to the inside of the sleeve before installing

 

[Deathrowdave]

I chased a leak and replaced rear main seal . Only to determine dip stick tube had a small unseen crack , causing the leak . Huge amounts of boost cause strange leaks