Leaking pinion seal...again?

[onion]

I don't quite understand your timeline here. You're saying that you went back to normal fill level after the first seal failed? Then switched again to a higher fill level after the second seal failure?

I still suspect that this overfilled condition is the cause of your problem. Overfilling a gearbox will lead to excessive heat buildup, and can make oil sling around in ways it was never intended to.

I read on your other thread that you have a 350+hp Cummins in this truck. This is a marginal application to start with, IMO.

[rant]350hp turbo-diesel in a pickup?? F*ckin' ridiculous if you ask me. I don't care if every Tom, ****, and Harry DOES have one... that don't mean it's a good idea. Wasn't long ago when your average class 8 road tractor, grossing 80,000 pounds, had a 350hp Cummins! [/rant]

I think that between this already marginal application, your regular towing, and an overfilled gearbox... you're cooking that pinion seal.

Or maybe you need to find a new mechanic... that's always a possibility.

 

[alreadygone]

My money's on Onion!

Bob

 

[deeter16317]

I'll explain it this way...

At around 75k I started running Royal Purple...that's 90k I've been running RP.

At around 110k, I change to fresh fluid and an ORU cover...it was overfilled at that point. I was told by several people running overfilled that it would not cause an issue.

At around 153k, the pinion stated leaking...just a seep. That's 43k miles overfilled, and again a LOW pinion axle is always flooded. This seal was replaced with a Mopar seal, that came pre-lubricated, and refilled.

At around 161k, the second seal started seeping...it was replaced with a GM seal (both dodge and GM use the 11.50AAM), I never saw this seal. At this point, I made sure the vent was open and the fluid level was at the OE location (as verified off the OE cover)...this was done purposely to rule out the vent being plugged and the overfill condition as causes.

Now at 165k (as it sits in the parking lot) it is leaking yet again. This seal was never run overfilled, and the vent is still open.

I have since overfilled to ensure I have enough fluid to limp home. An overfill condition obviously wasn't the cause for the failure this time, because it wasn't overfilled.

Again, I didn't fall off the turnip truck...a seal is able to run fully submerged if it and the sealing surface are in good condition. If you look at a low pinion, they are flooded at a normal fill, so my overfilling only added more volume to the diff. And further, if you study a differential, you would realize the oil is "pumped" through the pinion to cool the pinion bearings...the ring gear movement and scavenging is what pushes the oil through the bearings.

As far as the rating of the truck...you have taken that out of context, it is a STOCK truck. And if that was the cause, why did it wait 153k to show, then repeat twice within 12k?????????? Your logic doesn't make sense, sorry. I know a guy with 425k, running over 450HP, and towing heavy daily without a single leak. His truck should have melted down in the middle of the road somewhere according to your logic.

I have pretty much came to the conclusion I either have a sealing surface issue that is being overlooked or the seal is being damaged during install. My next step is to replace the seal and the pinion flange (the other half of the sealing surface) myself and see what happens.

 

[Mookitty]

It could be that you have a bearing starting to go, and it's letting the pinion wobble a little bit, eating up the seals.

 

[deeter16317]

I have considered that, but I have no indications...fluid is clear (no metal flake), no obvious play in the pinion.

If it comes down to rebuilding, I'll change gears to 3.73 or 3.42.

 

[onion]

Well, deeter, if I wuz you... I'd go with standard fill level and make [censored] sure that the new seal the correct part, and installed correctly. Not much else you can do.

Make sure the bearings and splines aren't loose... make sure the seal surface is good. Don't know what else to tell ya'.

Or if you're feeling brave... try the spring trick.

 

[Mookitty]

Hmm, maybe not an imminent failure, just wear adding up to provide some slack. Won't really know unless you can get a dial indicator onto the pinion shaft, and have some sort of reference so the numbers might mean something.

But dropping prop shafts for the kicks and giggles of a internet forum probably isn't your idea of fun.

 

[deeter16317]

The first seal was correct...dodge uses the VIN to identify parts. Not sure about the GM one, but a 11.50AAM is supposedly an 11.50AAM...

I've grabbed the pinion a couple times and tried to feel any play...nothing. I just pulled in (when I noticed this) from a 2600 miles run in 2.5 days...no whines, no vibrations. Yesterday I ran and cycled up and down from 70mph to 85mph to see if there was a noticeable vibration...nothing.

I'm going to try to replacing the pinion flange, and using a new seal. If that doesn't cure it, it will get completely rebuilt with new bearings.

 

[deeter16317]

The only thing with wear, assuming the shop installed it correctly, is that the pinion should have been re-tightened to the pre-exisiting preload. I would have assumed they would have noticed a pinion with no preload (preload should indicate no play).