Rear main or Oil Pan?

[PlumCrazy]

Whats more common on a 4.0?

There is oil coming from between the backingplate and the motor, but I cant tell whether it is from the oil pan gasket of the rear main, I was just curious if rear main seal go out commonly on the 4.0 or not

 

[Z3CHYD]

mine leaks there to. I think its either the rear main seal or the lower intake gasket...I have to add oil every 3-4 weeks...I added lucas to mine an its slowed down the oil consumption

 

[UrbanRedneckKid]

Just verify it's not the back of the lower intake manifold first.

If not, pull the trans back yank the clutch and flywheel out and take a look.

The trans has to be pulled for the rear main.
And the trans has to be pulled back to remove the engine to replace the oil pan gasket.

Either way your pullin bell housing bolts to fix it...

 

[calypso93]

On my 4L, with the A4LD, I took the front bell housing splash shield off. There was no oil there, so I figgered it wasn't the rear main seal.
It was leaking back near the starter, and showed up at the lowest point. I did a dye test and found it was one section of the oil pan gasket. I changed back to regular oil from synthetic, and in 500 miles or so the leak stopped. I realized coincidence is not always correlation, but, it doesn't leak now.

 

[AllanD]

Could be either... sadly you might have to take it apart to find out.

AD

 

[PlumCrazy]

Could be either... sadly you might have to take it apart to find out.

AD

I had the tranny out less than 1000 miles ago when I rebuilt it, but I nver pulled the flywheel off to check it out (since it wasnt leaking yet). Iam not loosing any oil really it is just wet and bothers me.

To replace the rear main do I just have to pull the flywheel and yank out the seal or does the oil pan have to cpme off?

 

[prerunin554]

I had the tranny out less than 1000 miles ago when I rebuilt it, but I nver pulled the flywheel off to check it out (since it wasnt leaking yet). Iam not loosing any oil really it is just wet and bothers me.

To replace the rear main do I just have to pull the flywheel and yank out the seal or does the oil pan have to cpme off?

A fair warning to you:
If it is damp, do not repair. If it is dripping, fix it. I have repaired hundred of oil leaks and always refused to repair anything just damp. The theory is that once you touch it, it becomes a problem. If it bothers you, don't look at it. Are you sure its not residual oil from your transmission repair? Maybe try cleaning the area/inside of the bell housing with brake clean and a pressure washer before you tear into it again. Once cleaned out, check back in a week or 2

 

[AllanD]

The seal can be replaced "in situ" but requires a small raft of special tools

And if the seal is bad I'd carefully check the engine for crankshaft end-play.

When a mainseal goes bad I'm one of those people that asks the pesky questions like "Why?"

The oil pan seal on a 4.0 is an O-ring so if I had to bet on one or the other
I'd guess it's the crank seal... not that it matters mch ecause to fix the oil pan seal requires pulling the engine out of the chassis

and without the special tools to extract and press the seal back in the
pan must come off to replace the seal, because the seal is clamped in the rear main bearing cap...

Either way I don't have any good news for you.

AD

 

[PlumCrazy]

A fair warning to you:
If it is damp, do not repair. If it is dripping, fix it. I have repaired hundred of oil leaks and always refused to repair anything just damp. The theory is that once you touch it, it becomes a problem. If it bothers you, don't look at it. Are you sure its not residual oil from your transmission repair? Maybe try cleaning the area/inside of the bell housing with brake clean and a pressure washer before you tear into it again. Once cleaned out, check back in a week or 2

It is not from the tranny. It is coming from between the backing plate and the motor, it is not in the bell housing. I know what ATF smells like and I know what brake fluid smells like it is neither so I know its not the trans or slave.

 

[calypso93]

If it's not inside the bell housing, I'd rule out the rear main. Ya can't beat a dye test....

 

[PlumCrazy]

If it's not inside the bell housing, I'd rule out the rear main. Ya can't beat a dye test....

It cant get into the bellhousing from the rear main since there is a plate between the trans and the engine. It is coming from between the plate and engine which means rear main or oil pan.

 

[ppeterso2]

Well, mine is a 3.0L-V6 and I found, at 99900 miles, that it was leaking from the RMS, Oil Pan Gasket and both valve covers--had to just yank the engine....I was going for a perfect game but couldn't get the timing chain cover to leak..LOL! I can only assume that an idiot owned the truck before I did and didn't change his/her oil regularly (or not at all until they traded it)... But now I have to assume that it tight because btw changes that dipstick level stays exactly in one place (full). It might be my imagination but the truck seems more responsive and seems to have more power now.

 

[Big Jim M]

I have repaired a whole BUNCH of rear main leaks simply by cleaning up the PCV system and installing a new PCV valve.. Too much pressure causes the rear main to PUSH out oil.

Try it you might like it.
Big JIm

 

[bighoss94ranger]

I agree with big jim, check & clean that pcv. Also, check the vacuum going to the pcv to make sure you have positive suction. This might save you a teardown. You never know. Hoss

 

[PlumCrazy]

The PCV valve and hose was replaced like 2 oil changes ago. It hasnt got any worse yet. My brother is finally done borrowing my 94 2wd, so when it warms up and all the snow melts I will pull the tranny on the 95 and investigate.