Rear Crank Seal Leak?

[CToney]

Just changed oil in my truck today and at the bottom of my bell housing where the slot is was damp with oil. Is it more likely my crank seal or input seal on the transmission? My clutch has started to slip when towing heavier loads. I will probably need a new flywheel and clutch too. If it is the rear crank seal I need a special installer to put the seal in I believe. Should I change the rear seal when I change the clutch anyways?

 

[Prairie Dog]

While driving down the highway the slop that comes out of my draft tube blows back onto that entire area making it look like a main leak. Could that be the only problem?

 

[rbattelle]

Besides what Prairie says, it's also very common for the rocker box gasket to be leaking at the back of the head. The leaked oil travels down the back of the engine and collects exactly where you're seeing it.

Is the truck leaving drips of oil on the ground?

-Ryan

 

[Ram4Sam]

There is always the chance it is the trans(input shaft) seal. I remember reading somewhere that the trans seals aren't noted for longevity. Park it nose down for awhile and see if it drips more.



Sam

 

[rscurtis]

Ditto on what Ryan said. My signature truck has a slight leak that looks like a seal leak, but I removed the inspection cover and the inside of the BH is dry as a bone. I can see evidence of the leak on the back of the head. I have a few more projects to finish before I get to this one.

 

[cerberusiam]

Could be crank seal or input shaft seal. Could be the crank case vent tube also.



No lifter box gasket on a CR so any oil coming from the back of the head could be a leaking HG, VC, or other oil source.

 

[rscurtis]

Note that Ryan referred to a rocker box gasket, not a lifter galley gasket. It's a "V" shaped "O" ring between the head and the aluminum housing that contains the wire connectors for the injectors. It floats between the two surfaces, as the perimeter of the rocker box stands off the surface of the head.

 

[CToney]

I never noticed an inspection cover on the bell housing. I'll put a piece of cardboard under the truck to see if I get a puddle. I sure seems to be coming from that slot. My brother's old '93 had a rear crank seal leak that was quite bad but it didn't affect his clutch. I will probably take it to the same mechanic. I don't have a transmission jack or some of the other necessary tools to get the job done.

 

[rscurtis]

The manual transmission bellhousing does not have the inspection cover according to what you have said. If you suspect the RB gasket, look toward the back of your head on the injector side. If you see any dampness, that could be the problem. It's also an easier repair than R&Ring the transmission and clutch.

 

[Shadrach]

I had oil dripping off the bottom of the bell and it turned out to be the turbo drain gasket leaking and running back and down to the bell. for leaks always look up first. Shad

 

[DE Jeeper]

my oil leak came from the oil cap and the crank case breather drain. an oring and hose clamp fixed the problem. i suggest you pull the plasic cover and check to see if the oil is coming from the top of the motor. how many miles do you have on the truck.



aaron

 

[Tumbleweed]

The very slow leak that was showing up around bell inspection cover plate turned out to be leaking input shaft on the 48RE. Since they had to remove trans to do the repair , they also changed my rear crank seal which was not leaking, but did it on warranty. They said the mileage I was at they were very prone to leaking. I think it was around 150,ooo kms. ( 93000 miles )