Rear main leaking after replacement

[vtach]

So I had a bad leak in the rear main seal and had it replaced. Now about 135 miles later, it looks like it is starting to leak again. The guy that changed it out is a diesel mechanic, and I am sure he knows what he is doing. My question is, should I just live with it unless it gets really bad again?
But an the other hand, I don't want to drive it around in fear that it is going to really let go like the last time.

 

[FMJ]

Same deal with mine, I replaced it with the new style, more expensive, higher temp version, but after just 50-100 miles it's leaking again. . . checked the breather, not clogged, replaced the air compressor, it was leaking oil from the intake, turbo seems to be ok, some oil from slobber tube, but not alot. . .

Only thing I can figure is there is a defect on the crankshaft where the seal mates to it.

 

[cranetruck]

It may not have been done correctly, we are all human.

See TM 9-2815-210-34-2-2 for procedure.

Leonard Jones did an expert job on mine back in '06.
Images show him drilling the drain holes and me doing my part, cleaning.

 

[JDToumanian]

Fascinating, Bjorn... I fail to see what difference it makes though. Is a 1/4" hole really too small for the oil to drain out of the seal?

I would assume, since my engine was manufactured in 1987, that it already includes this upgrade? When I did a clutch job a few years ago I did not replace the seal, because it showed no evidence of leaking, but I wish I had.... It still does not leak, fortunately.

As for why new seals might start leaking - another possibility is that the old seal wore a groove into the crank. Even a slight groove, barely perceptible to the eye but usually able to be felt with a finger, can change the tolerance enough to cause leaking. A solution is to install a "Speedy Sleeve", a very thin steel sleeve that is pressed or loc-tited onto the crank to restore the running surface for the seal.

Jon

 

[jwaller]

I would bet that a speedy sleeve is whats going to be needed in this guys case.

I do believe the holes will help as this is also what gm recommends on the 88-up 1 piece rear main motors.

 

[FMJ]

It may not have been done correctly, we are all human.

See TM 9-2815-210-34-2-2 for procedure.

Leonard Jones did an expert job on mine back in '06.
Images show him drilling the drain holes and me doing my part, cleaning.

Mine already had this modification. So I'm leaning toward the surface on the crankshaft. After the sleeve is installed, is the same seal used?

 

[gringeltaube]

There is a problem with the new style seal and the aluminum seal retainer: it covers ALL 3 holes because it has an inner backing shield! (When I had asked the vendor about this the answer was most MF engines don't have a seal retainer and drilling holes wouldn't make a difference...!!!!)

Well, ALL MF engines I have seen have that retainer, some already upgraded with 3 holes like in Bjorns diagram.

Just in case I decided to drill the NEW seal through after pressing it into its retainer.
It stayed dry for now... but now I don't know... : does it seal because its a better seal or because enough oil still DOES drain back into the crankcase...?

G.

 

[FMJ]

Well that answers that question...In reality, I now have no drain holes with the new 100.00 seal installed. . . I hate pulling the tranny on a winch truck. . .


Sorry to hijack your thread vtach

 

[FMJ]

There is a problem with the new style seal and the aluminum seal retainer: it covers ALL 3 holes because it has an inner backing shield! (When I had asked the vendor about this the answer was most MF engines don't have a seal retainer and drilling holes wouldn't make a difference...!!!!)

Well, ALL MF engines I have seen have that retainer, some already upgraded with 3 holes like in Bjorns diagram.

Just in case I decided to drill the NEW seal through after pressing it into its retainer.
It stayed dry for now... but now I don't know... : does it seal because its a better seal or because enough oil still DOES drain back into the crankcase...?

G.

Wait, Isn't that pic of the new seal showing the surface that faces the tranny?, and the pic of the retainer showing the side that mates to the block?

 

[gringeltaube]

So I must have installed the new seal backwards then.... maybe for submarine usage only......???


No, seriously: see another pic from that same seal (installed) viewed from the "tranny" side.

G.

 

[FMJ]

So I must have installed the new seal backwards then.... maybe for submarine usage only......???


No, seriously: see another pic from that same seal (installed) viewed from the "tranny" side.

G.

Thanks G,

I'm at work at didn't have my extra seal to look at...

Ed

 

[jmh4x4]

Ok, Im am totaly confused at this point, hopefully when the time comes and I need to replace one, I can bribe one of you guys with plenty of adult beverages and other items to walk me through it.

 

[FMJ]

Mine already had this modification. So I'm leaning toward the surface on the crankshaft. After the sleeve is installed, is the same seal used?

Anyone have any info on the proper size and where to obtain said sleeve?, and the seal question?

I only want to pull this tranny ONE more time. . .

 

[FMJ]

I found this info with a google search, anyone know what size the rear main shaft on the LDT-465 is?