I have a 93 Dodge with a Cummins, leaks engine
oil out the bottom at the rear underneath the flywheel.
Leaks mainly when it runs!! Vehicle has 80k on it.
What could be leaking?
Thanks

 

It's probably the rear main seal. Mine had a slight drip until I put in a bottle of engine stop leak designed to make seals rubbery and swell up a bit.

 

More than likely the rear main seal or the seal adaptor gasket.

HTH

PS Fill out your signature

 

Could also be the rear valve cover gasket is leaking and running down the back of the block, making it look like a rear main seal.


Flash.

 

most likely a rear main seal like mine .......it just wants to mark its territory......i wouldn't worry about it.......i dont i just watch my oil levels i check my oil at least once a week and keep a spare qt of oil in the truck with me at all times

 

I put some stop leak in the crankcase to try to slow down the vacuum pump leak, which it did, but looks like the rear main might have blown out on my way home today. Cummins want's about $1,300 to do it. What is involved if I do it? Can I unbolt the front mounts and lift the engine engough to get the pan out? Can I sneaky pete the seal? Do I change out the thrust bearing while I am in there?
Help needed please!
Thanks,
Mark

 

Pan does not come off, the trans has to come out. It's a one piece seal.

 

Can I just back the trans and transfer case out of the way enough to get at it?

 

Heres what it looks like w/ the trans out.
this is a 93 CTD
Scott

Groan, i need to do same to my 92.... not a big deal just gotta find the time.

 

I have pulled and installed gasser engines and trannys many times, but not a big diesel. Is this something I should attempt? I can go get a couple of tranny jacks from Horrible Freight I guess..... I'm in a bad way cause I don't have a backup vehicle and funds are pretty low right now... can't afford a Cummins job.

 

I have an 800 lbs trans jack from harbor freight and it worked great for pulling my 205 and 518 (not hooked together, though).

 

I would pull the engine rather than the trans and transfer case. When you have the engine out maybe check the oil pan for leaks also.

 

Never, never, did I say never, put any additives in a CTD engine. Very bad idea and not recommended by Cummins at all. You will just have to roll back the tranny to replace it. Do yourself a favor though and pull the seal adapter and install the seal on the bench, replace the seal adapter gasket and reinstall. Make sure the seal is installed perfecty dry or it will leak. Check the crankshaft for a groove worn where the seal rides on it. If it is worn bad you can sleeve it or place the main seal in a little different depth so it will ride on a good part of the shaft.

 

Maybe I can take the x-members and slide the whole mess back enough to get at it???? This is one time having a 4x4 kinda stinks!
I have a new racing vacuum pump that I could plumb into the second exhaust pipe, I, I mean the crankcase vent tube and put negative pressure in the engine to stop the leaks!

 

Be very thorough in checking for the leak when you have the transmission out.

Friend of mine had his transmission out three times to replace the rear seal, not an easy job at best, worse with his 4x4. He could not figure out what he did wrong replacing the seal, especially after the third time.

When it still leaked just as bad with the third seal installed he had one more look. This time he pulled the adapter plate and found that the welch plug behind the camshaft had worked it's way loose, causing it to leak. You can see the plug in Proram's photo at about the 11:00 o'clock position relative to the crank.

Apparently the oil ran between the adapter plate and the seal housing into the bell housing, and after being thrown around by the flex plate and torque converter he was sure the the rear seal was leaking again.

This is probably not very common, but just a word to the wise not to overlook anything. Ask my buddy how he knows.