Jeep Wrangler Forum banner

1 - 6 of 6 Posts

·
Registered
Joined
·
3,072 Posts
Discussion Starter #1
In five years I have had to replace 5 Rear Main Seals and 5 Release Bearing.

I think it is either a poor design or another issue more like a worn main journal bearing or, could it be the harmonic balancer?

Any known causes or ideas?

I am toying with the idea of having my engine torn down to maybe find the real culprit because I don't hear of other Penastar 3.6 engines with this constant trouble.
 

·
Premium Member
Joined
·
1,805 Posts
As an engine builder for over 50 years I assure you the cause can be any number of things from undersized or out of round journals to poor line bore or balance issues from anywhere in the engine or transmission. Tearing down the engine could end up being a waste of time since unless you intend to basically blueprint the complete engine you're not likely to find the cause. Even a slight misalignment of the mounting pattern between the engine and trans could be at fault. The trans itself could be the cause due to a tweaked input shaft or bearing or even a balance issue with the clutch or flywheel.

All this being said, the most common cause is a problem with the journal where the seal rides but after 5 replacements you're not likely to find a cause if you haven't already. I would have to ask, Are you sure the main seal is where the leak is coming from? And why was the release bearing replaced every time also?
 

·
Registered
Joined
·
1,936 Posts
Just thinking out loud ... Could it have anything to do with the crank thrust bearings, and possible excessive axial movement of the crankshaft? With a manual transmission, could the thrust load from disengaging the clutch be causing wear issues?
 

·
Premium Member
Joined
·
1,313 Posts
This is way out there, but a leaking oil cooler can have oil coming down the back side of the bell housing and appear as a rear main seal or transmission leak.
 

·
Registered
Joined
·
1,586 Posts
I have a buddy with a nearly new JL that's on it's 4th rear main seal. They voided his entire warranty after the 3rd one because the chassis was dirty and he was "off-roading" so it's "abuse".

Where to you 'wheel? I've had all kinds of seal issues off-roading in the Everglades- the sugar sands kills oil seals. I've lost 4 axle seals and a rear pinion seal so far. I think the sand scores the journal.

From my muscle car days, I remember there being a sleeve kit to repair a crank shaft that has a groove worn in it from a seal. It's a thin metal sleeve that you loc-tite over the snout of the crank so the seal has a new surface to run on. Just a thought.
 

·
Premium Member
Joined
·
1,805 Posts
From my muscle car days, I remember there being a sleeve kit to repair a crank shaft that has a groove worn in it from a seal. It's a thin metal sleeve that you loc-tite over the snout of the crank so the seal has a new surface to run on. Just a thought.
The only such repair sleeve I'm aware of was for the front seal. I wouldn't even try such a thing on the rear since there would be no way to actually capture it like we did on the front.
 
1 - 6 of 6 Posts
Top