Engine/Transmission (1998.5 - 2002) Replace or not replace the rear main seal?

[fj40charles]

I need some expert opinions on whether to replace the rear main seal when I install the SBC clutch.



My truck has 76,000 miles on it and I don't have any leaks from the rear main seal. (no leaks that I'm aware of). I bought the truck new and have changed the oil (Rotella T) every 3-5K miles.

It is a 2000 model truck.



I'll buy the Cummins seal/driver kit. Cost of seal and install is not a factor in my decision.



My questions are:



1. What is the life expectancy of the rear main seal?

2. If there are no leaks, will I do more damage trying to install

a new seal? I would hate to install a new seal and have it leak.

3. How hard was it to drive the seal in without ruining the seal?

Does the Cummins supplied seal driver work?

4. Should I just leave the seal alone and take my chance?



Thanks in advance,

Charles

 

[fj40charles]

BTW, I did search, but did not see anything about having more problems after installing a new seal when the original seal did not work.

 

[M Barnett]

I would change it. I recently put in a SB clutch and didn't change the seal. Now its leaking.

Michael

 

[fj40charles]

ttt

ttt

 

[A Johnson]

The seals can last a long time or they can go out at any time so its your decision.

They are not hard to do, yes the supplied driver works good if used correctly. It is easy to get the seal started crooked and when driving it in, one side will go too deep, so here is what I do.

Get some 7/16 fender washers, stack 3-4 of them on three of the flywheel bolts. Get your seal sitting on the crank and remove the plastic starter sleeve, put the seal driver over the seal and pull the seal in with the bolts and washers one turn at a time. When you get to the bottom the bolts may not pull the seal driver all the way down, I then lightly tap on the driver untill it is seated. Easy wasn't it?

Be sure to have the crank clean and dry. I also like to use permatex #2 around the curcumfrence of the seal housing.

Some people like to pull the aluminum housing and press the seal in on the bench but I would rather not deal with a possible leaking pan gasket. Good Luck. -A Johnson



P. S. I would change it

 

[bighammer]

Doesn't sound so bad... ..... kind of wish I did mine. Hope it behaves.

 

[Texas Diesel]

Originally posted by A Johnson

Get some 7/16 fender washers, stack 3-4 of them on three of the flywheel bolts. Get your seal sitting on the crank and remove the plastic starter sleeve, put the seal driver over the seal and pull the seal in with the bolts and washers one turn at a time.

This site is great isnt it?

 

[keimmmo]

The original seal failed on my '92 at 75k. Dealer installed new one under waranty. Still going strong without a leak with over 300k on it now!!! The replacement seal was far better quality than the OE! Dealer gave me the replacement tool just incase I needed it someday...

 

[WestTN]

main seal

My old 1989 CTD now has over 245,000 miles and still has the original seal. No leaks.

I can't believe Cummins would put a cheap seal into a new engine, knowing they would have to fix it. If they would take a shortcut like that, these engines would be full of junk parts. On an engine this expensive it would be sheer stupidity to install a seal which they would only save a couple of bucks on.

 

[A Johnson]

These seals almost never leaked between the Teflon lip and the crankshaft when installed properly.



The two most failure modes that I have seen are as follows:

1- The rubber seal ring that sandwiched between the two half's of the laminated steel carrier, would swell up and break apart causing a leak between the lamination. This failure would typically leave tiny black rubber pieces in the bell housing.



2- The loctite that held the seal in the housing would fail causing the seal to spin in the housing.



I don't know what the date the current seal was released, I would guess 1996 or so. This seal has a rubber coating that seals to the housing, very tightly, I have not seen this fail.



Not every seal failed, but alot of them did. - A Johnson