Rear main seal

[reno]

How hard is it on the 4.0? Does not look like enough room to remove the oil pan with the motor still in, and still does not look as if it will come out even if I break the motor mounts loose and lift the engine. Do we have to pull the engine to do this? Seems like a PIA.

 

[MAKG]

Either the engine OR the transmission has to come out.

 

[AllanD]

remove the pan in the chassis? Noo, you can't.

HOWEVER, on a 4.0 the rear mainseal id held in not by the oil pan bu by the rear mainbearing cap.

It is a one piece oil seal that CAN be replaced withour removing either
the pan or the bearing cap.

Provided you have access to the special tools....

But if the seal is bad you've gotta ask why the seal is bad...
Typically it's because the crank is "walking" fore-aft in the block due
to a worn thrust bearing.

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[MAKG]

I thought the special tools were a pair of screws and a slotted screwdriver.

Though it sure as heck is a 1000 times easier to get it out without swearing by just removing the rearmost bearing cap.

I just gotta avoid teaching the 3 year old the art of creative swearing....

 

[Big Jim M]

Guys...two things.

First is maybe there is excessive blowby causing the oil to be pushed out the RMS.. So maybe checking the pcv system would stop the leakage..

Second...How do you get a one peice seal on the crank without pulling either the tranny or the engine?

Big JIm

 

[reno]

I will have to look again and make sure it is the rear main, I discovered a very very small leak. It is time for a oil change (actually overdue by about 200 miles) and I was low about 1 quart. When I looked underneath, I seen oil where it has been dripping around the bell housing, started to rain so could not look real good. If it is not raining when I get home today, I will look again. If it is the main, I guess the hardest part is pulling the Transmission\Transfer out? Is the hydraulic throw out bearing replacable or do I have to buy the entire hydraulic assembly? This is what AZ shows to replace http://www.autozone.com/selectedZip,33542/initialAction,partTypeResultSet/initialN,15300534/initialNtt,/initialNo,/shopping/selectZip.htm

 

[MAKG]

It is also VERY common to mistake certain oil pan leaks, and even certain valve cover leaks, for a leaky rear main.

Oil pans very commonly leak at the rear; there is almost always a couple of corners in the gasket there. Valve covers (and even lower intakes) can drip down to the bottom of the bellhousing as well.

If the rear main truly is leaking, it may be due to crankcase pressure because of a plugged PCV valve or excessive blow-by, or it may be that the crank has a groove worn in it. If it's the latter, you need to "sleeve" the crank or it will leak again, instantly.

 

[reno]

Guys...two things.

First is maybe there is excessive blowby causing the oil to be pushed out the RMS.. So maybe checking the pcv system would stop the leakage..

Second...How do you get a one peice seal on the crank without pulling either the tranny or the engine?

Big JIm

I know what type they are talking about, done them before, don't need sneeky pete either. It sits\seals right behind the flywheel on the backside of the crank. The spring side of the seal goes in first and use a piece of pvc and gently tap it in. Makg, you pull them the same way I was taught . I use 2 screwdriver, sometimes a block of wood and my pry bar that looks like a oversize screwdiver.

 

[reno]

It is also VERY common to mistake certain oil pan leaks, and even certain valve cover leaks, for a leaky rear main.

Oil pans very commonly leak at the rear; there is almost always a couple of corners in the gasket there. Valve covers (and even lower intakes) can drip down to the bottom of the bellhousing as well.

If the rear main truly is leaking, it may be due to crankcase pressure because of a plugged PCV valve or excessive blow-by, or it may be that the crank has a groove worn in it. If it's the latter, you need to "sleeve" the crank or it will leak again, instantly.

"Sleeving" would be changing rod\main bearings to oversize?

 

[MAKG]

No, it means putting a new surface for the seal to ride on. It has nothing to do with the bearings.

You CANNOT use a sneaky pete on a one piece seal. It goes around the crank with no breaks and you simply MUST have the flywheel off in order to remove it. How anyone can get a flywheel off (in one piece, at least) without separating the engine from the transmission borders on science fiction. I guess you can "beam it out."

 

[reno]

No, it means putting a new surface for the seal to ride on. It has nothing to do with the bearings.

You CANNOT use a sneaky pete on a one piece seal. It goes around the crank with no breaks and you simply MUST have the flywheel off in order to remove it. How anyone can get a flywheel off (in one piece, at least) without separating the engine from the transmission borders on science fiction. I guess you can "beam it out."

That is why I said that I DO NOT need a sneeky pete. And I also said the hardest part seems to be pulling the transmission\Transfer out. But I must double check this leak first, and guess what, it is pouring outside right now

I have done these type of seals before, just did not realize that the 4.0 had them.