D7G Rear Crankshaft Seal

I started getting engine oil in my transmission fairly suddenly. The rear crankshaft seal seems to be the only way for this to happen. This is on 92V23xx with 3306.

I'm curious why it started leaking suddenly. We'll have the torque out before long. Got my fingers crossed that the thrust bearings aren't bad. This is a fairly low hour engine that hasn't been using any oil. I bought the machine at an auction and the engine was built by an established company out of Dallas.

I have done the rear seal before on these engines but I'll be danged if I can remember how I did it. I think that I took the wear ring and heated it in oil to slide on and then used the old one to drive it home. I know that Cat wants me to use the special installer.

I see a "C" (changed) for the 6N8853 rear crankshaft seal number. I wonder if a former seal was different and had problems.

Might have changed seal material. I'm almost positive that the last one or two that I installed had black seal material and not the burnt red of this NOS 6N8853

https://www.ebay.com/itm/Genuine-Caterpillar-Crankshaft-Seal-6N8853-7C4297-3256192-325-6192-/291756595258

Like this one:

https://www.ebay.com/itm/Caterpillar-7C4297-Oil-Seal/132105722487?epid=1504120334&hash=item1ec21d5a77:g:kT0AAOSwdGFYrxsT

Seems there is a variety of part numbers for the 3306, some single lip and some double lip.

Hi Team,it is a veritable mine field finding the correct seal for each application and the correct tooling that must be used or the very expensive seal will be rendered useless.
The data I have here would be too out of date to warrant posting.
The last double lip hydro-dynamic seals I fitted at The Dealer had an inner steel sleeve that is to be pressed onto the crank flange at the exact some time as the seal itself--all in one motion with a Special Tool.
IF the sleeve is removed the seal lips with their hydro-dynamic grooves are cut/distorted and destroyed.

I guess some people have been lucky separating the seal components in the past, BUT I would never try it as Cat know their design and its idiosyncrasies.

Seems you have been to The Dealer and may know about the Special Instruction that describes the fitting procedure--the Form Number I have here would likely be out of date but you can ask for a copy of it or its updated version :- Form No SMHS 8508.

Older Service Magazine articles covering data on these seals and their usage I have that are likely out of Date also are :-
September 28-1987, May 23-1988, and October 17-1988.
The Dealer Technical Service Dept. or equivalent today, should be able to furnish copies.
Copies I have are poor as they are copied from Microfiche many years ago.

Hope this helps.
Cheers,
Eddie B.