rear seal leak

[fanzdslpwr]

my 2003 d-max dually 4x4 is leaking what appears to be gear oil on passenger side rear. is there any additive i can dump in my rear diff to stop the leak?

[DmaxMaverick]

NO ADDITIVE!

Only option is to replace the seal, then correct the problem that caused it. There are 2 reasons, short of a defective seal, that can cause the seal to fail.

Overfill. If the lube level is too high, internal pressures can overcome the seal.

Blocked/trapped vent line. If the vent line is blocked in some way, the pressure has no escape, except the seal(s). Also, if the vent line is looped or dipped (creating a trap, like a sink drain), lube will accumulate in the trap, and prevent proper venting of the pressure.

There has been some controversy over the correct fill amount. At first, GM recommended 4 qts, or even with the fill hole. Later (obviously after some leaky seal complaints), the fill was reduced to about 3.4 qts, or about an inch below the fill hole, which supposedly stopped the leak complaints.

What I found, a couple services ago, was both fill recommendations were correct, depending on how the service is done. If I just drained and filled with 3.5 qts, the level is about 3/4" below the hole. If I drain and pull the axles, allowing the lube to drain from the axle tubes, then refill, 4 qts. gets it to about 3/4" from the fill hole. I think GM's service recommendation of 4 qts. is for a dry axle, or first fill, and the 3.4 qts. is for a service fill. When I do the axle drain, once refilled, I jack up one side for a while, then the other (to make sure the bearings get a good bathing), then do a quick heat-up cycle up the road and back, then recheck.

If you have a seal leak, pay very close attention to your brake condition. Once the lube saturates the brake pads, they need to be replaced. In some cases, a little lube on them can be cleaned up. If they've been soaked and heat cycled, they are toast.

Hub work on these axles is relatevely simple. If you don't have to get into the hub, the rotor can be removed without removing the hub. The brake caliper is the only thing keeping it on (once the wheel is removed). If you do remove the hub, follow the R/R instructions very carefully to ensure proper bearing load. The procedure has been updated recently, so make sure you get the latest bulletin.

[fanzdslpwr]

i am starting to think that maybe it was overfilled. i just purchased the truck and its a 2003 and i want to make sure i didn't buy someone elses problem. i do no the oil in the rear diff is completely black and needs to be changed.

[dmaxalliTech]

If its leaking, it needs to be replaced, there is nothing you can do with fluid levels/conditions to stop it.

[70runR]

Any special tools needed to change the seal? I too have a leak in the passenger side rear axle. Also, are these 9.5 or 10.5 rear axles in the 2500HD GMC's? Where can I obtain the R&R procedure? Thanks again. blmen@cass.net

[DmaxMaverick]

Originally posted by 70runR:
Any special tools needed to change the seal? I too have a leak in the passenger side rear axle. Also, are these 9.5 or 10.5 rear axles in the 2500HD GMC's? Where can I obtain the R&R procedure? Thanks again. blmen@cass.net Welcome to the Forums!

Only "special" tool needed is the wrench for the axle nut, and a torque wrench. A seal tool is handy, but not necessary if you are handy.

The ring gear is 11.5" (big, huh?). Same as the 3500.

Be careful where you get your R & R procedure. It has been updated since the first release with some VERY important info. The precedure you need involves torquing, loosening, then hand-tightening of the nut (that's not the whole procedure).

You can buy a manual from Helm (http://www.helminc.com) ($$), or an online subscription to AllData (http://www.alldatadiy.com) (much less $$). I use AllData. The paper manuals are nice, but dated. AllData is updated frequently, and includes all TSB's as well as all the info you will find in the manuals. The search feature is a lot more handy than an index.

[Dale_S]

What is the story on rear wheel seal leaks? I found oil on the inside driver side rear wheel while checking the tire pressure. I went to the dealer and ask if this is a common problem. He said he sees a leaker from time to time but no recall or service bulletin. From what I read on this forum it seems to be a recurring problem.My truck only has 41K miles on it. I should think wheel seals should last longer than that. If this is a known issue at GM maybe they will do something about it.

Dale_S

[kevincolliver]

my 02 2500hd has 57k on it and leaking from the passenger rear as well.

[cday]

My 2003 2500hd with 45000 miles is leaking on the left rear axle. Seems like a premature failure to me.

[Jim Brzozowski]

DmaxMaverick, How many seals rear wheel seals have been replaced on the 85 Blazer with the 1/2 million miles?
I wonder how many rear wheel seals that guy in Georgia replaced on his million mile silverado that was reported on a year or so ago. Pennzoil got the truck from him and gave him a new one. The old truck was a 95. Anybody know?

[DmaxMaverick]

Originally posted by SoTxPollock:
DmaxMaverick, How many seals rear wheel seals have been replaced on the 85 Blazer with the 1/2 million miles?
I wonder how many rear wheel seals that guy in Georgia replaced on his million mile silverado that was reported on a year or so ago. Pennzoil got the truck from him and gave him a new one. The old truck was a 95. Anybody know? No seals. The rear ends (10 bolts) only lasted about 100K, so I never really got to the expected lifespan. The last ~250K has been on a 12 bolt (w/ the ratio upped to 4.10 from 3.73) with no failures. I got really tired of overhauling those 10 bolts every couple years. The housing may not have been true, causing the carriers to grenade. But, I expect the way I treated them had something to do with it.

As far as the full floaters go, you either have problems, or you don't. I've had (and have) several and only one ever leaked. Then, it was always the same side with a predictible failure time/miles. It wouldn't take much of a flaw on the sealing surface to wear away at that thin rubber, which can lead to dynamic seepage.

[windjammertx]

On my 02 2500HD, the rear seals failed first at 44,000 and next at 58,000.
windjammertx
02 2500HD Black CC 4x4 LB

[Modified]

I don't believe the leak is level related either.
-Truck new Oct "01"
-Aug "02" @ 17K miles-Installed MagHytek rear diff cover and eight qts 75W90. Level is well above the factory fill hole.
-Mar "03" @ 39K miles replaced both rear axle seals
-To date, 70K miles and no leaks.

I always thought this was due to a restricked vent. I slightly rerouted the soft vent tubing all the way to the fuel tank fill hose, to ensure a continuous slope, to ensure any liquid in line drains to the differential. I also ensured the soft vent hose had no kinks. I very cxarefully install tyraps to hole tube at constant slope, but was careful not to pinch vent hose closed.
(Knock wood), no seal leaks since, may be too soon to tell.

[FrankA]

mine went at about 50,000.

[DmaxMaverick]

Originally posted by Modified:
I don't believe the leak is level related either....It is.

Maybe not as much in your case, with a Mag cover. The shape and construction of the cover has a lot to do with it. The OEM cover closely houses the ring gear, which will allow for a "pumping" action. The Mag cover has much more clearance, so the oil may not be forced onto the vent hole. The problem with the overfill is the lube is crowded near the vent, causing it to go into the tube when heat expansion occurs, and any "traps" in the vent tube will prevent the lube from draining back into the diff, blocking the line from air venting. It could be the lube is actually thrown onto the vent hole with an OEM cover and overfill.

Overfill your Mag-equipped diff, and you'll have the same condition. The design may just allow more fill level flexibility. Also, with more lube and fins to aid cooling, there will be less thermal expansion, which will lessen the demand on the vent.

One problem we will have when diagnosing a seal leak issue (or any issue, for that matter) is the actual cause. The axles, by nature, will have some failures, due to manufacture defects. It happens. Can't avoid it. Like many other issues, if we blame the wrong cause, the problem will likely return in a short time. Again, and again. I'm not saying this will be the cause every time, but probably more often, than not.

[Plasticfantastic]

52k miles, have left rear leaking. It's been about six months since I changed the gear oil, a little late for an overfill to show up.
Are you guys saying you can pull the axle without removing the pumpkin cover? I'm just used to older GM where the c-clips have to be pulled.

[DmaxMaverick]

Originally posted by Plasticfantastic:
52k miles, have left rear leaking. It's been about six months since I changed the gear oil, a little late for an overfill to show up.
Are you guys saying you can pull the axle without removing the pumpkin cover? I'm just used to older GM where the c-clips have to be pulled. The C clips were never used with a full-floater R/E. They were only present in light duty semi-floaters (1500 and older 2500LD) The axles can be pulled by removing the 8 flange bolts (at the outermost end of the hub). Once the bolts have been removed, the axle will slide right out. You may have some adhesion with a gasket, but there is nothing holding the axles in, other than the flange bolts.

[Plasticfantastic]

Thanks Mav, think I'm gonna get the alldata and cancel my app at the dealership for next week.

[DmaxMaverick]

Originally posted by Plasticfantastic:
Thanks Mav, think I'm gonna get the alldata and cancel my app at the dealership for next week. Alldata is a good idea. There will be some pretty important R/R procedures. When reinstalling the hub, be sure you use the torque, loosen, hand tight method. It was updated, but the old one may still be listed. Torque spec's with everything you'll be getting into are critical, but not too bad of a job overall. Check the condition of the E-brake shoes closely if any lube got to it. If there is any significant amount, replace them.

Anything else you'll encounter has been covered, so try a search if you get in a bind. Or, just come back with your questions.

[Plasticfantastic]

I stopped off and picked up a seal today. Signed up for Alldata... now I'm lost. I guess I expected the Alldata to have a step by step page on r&r of the seal with all the torque specs laid out? I've been searching through this thing for an hour, it even has a help section describing how to get to "repair information" but that doesn't lead to any of the clipboards it says hold the info...
I see a lot of tech specs on different things, tons of TSB's but no play by play of any individual repairs?
I picked up an exploded view at the dealer and it looks really simple, I read through a dozen archives and it seems straightforward, I was just hoping for a page of info that pointed to specific things and said "do this in this order", "torque to this". I think changing the seal is gonna be easier than trying to decipher the alldata flow chart tongue.gif .


Jeff-

[DmaxMaverick]

It's there.

Try this.

After selecting your vehicle acct, click on "Transmission and Drivetrain" in right column.

Click "Differential Assembly" in right column.

In the left column, under "Service and Repair", click on "Rear Drive Axle".

In the right column (at the bottom), click on "Hub and Rotor Assembly Replacement". That will get you to the hub R/R procedure.

The "Seal replacement" procedures seemed to be a little moronic. Kinda' like teaching an adult to drink from a cup (if you can do this, you'll have no problem).


For the hub torque procedure, go to "TSB's", then "All TSB's", then select "Drive Train - Revised Wheel Bearing Adjustment Procedure" (it's about 2/3 down). Apparently, they pulled the previous procedure from the regular "manual", to be sure we use the updated TSB.

Between the two pages, you should be able to get through all the steps necessary to complete the job.

[Plasticfantastic]

EASY! Thanks Mav!
I kept doing "drive axle" then "wheel seal"... and getting nowhere over and over.
BTW, know what the definition of insanity is?? ...doing the same thing over and over and expecting a different result. :D
It does look pretty much as I expected in the diagrams and all the archived info lays out some of the quirks folks have had. Confidence is high! Wish me luck.


Jeff-