The penguin's motorcycling and Jeep blog

Thursday, August 21, 2008

Leaky rear axle

The last time I changed the differential fluid in the rear of my Jeep, I apparently missed a spot with my RTV bead when I installed the differential cover. It's been doing a slow drip... drip... drip... ever since. Not a lot. If I left the Jeep sitting in one spot for a week, I might see a small quarter-sized spot of fluid on the ground. But a rear axle don't have no oil gauge or nuthin' to tell ya that it's low on fluid, so it was a PITA to get under there and pull the plug and check it and pump a few ounces more fluid into the axle every now and then, especially since the plug is partially hidden behind the gas tank so you literally have to *pump* fluid into the thing unless you jack up the body a bit.

So anyhow, it's getting close to the time where I should change it anyhow (I have 22,000 miles on the Jeep, I should change it at 24,000 miles because it's a limited-slip Dana 44 and the plates wear and there's no oil filter so the only way to get that crap out of the differential is to dump the fluid every 12,000 miles) so tonight I took the bikes out of the garage and parked them beside the apartment building, and backed the Jeep into the garage. Now, one reason why I didn't do so well on the rear axle last time was because the rear axle is partially hidden by the gas tank skid plate. So this time, I stuck the Hi-Lift farm jack on the back bumper of the Jeep and jacked it up a little. Not enough to get the wheels off the ground, just enough to lift up the body of the Jeep so that the rear axle wasn't buried so deep by the gas tank. Boy, I'm glad my Jeep has a nice sturdy steel bumper instead of that plastic bullshit on the modern vehicles!

So anyhow, I just popped the differential cover bolts off, whacked the cover a few times with a rubber mallet to get the old RTV to let loose so I could pull it off, and let the fluid drain into the drain pan beneath it. Then I cleaned everything off with a gasket scraper, then brake cleaner (ooh! ether! whoooo!), and put a bead of black RTV around the cover and slapped that sucker back on and torqued the bolts to 30 ft/lbs. So now I'm waiting an hour for the RTV to dry, then I'm going to head back down and put in the differential fluid -- Royal Purple 75W140 synthetic, in case you're wondering (that's the recommended viscosity for this differential when used for off-road duty, and Royal Purple comes with the limited slip additive already included).

Next up, I get to take it to the dealership for a warranty repair on the seat, which seems to have a broken recliner mechanism... grrrr!

-- Badtux the Jeepin' Penguin


w3ski said...

A word of caution ; always examine the cover and housing area for
" dents " . I've seen good sealant jobs fail due to a
' tang ' of metal , left over from a previous scraping . Hardened scrapers and over enthusastic techs can lead to a bit of filing to make it sealable again .
I'd say run your finger around the sealing area first , EXCEPT I know that is a great way to get a deep cut when you find that tang .

BadTux said...

In this case I'm the only one who's ever touched this axle since it left the factory. I don't trust the interns that shops put in charge of doing brainless shit like this. But anyhow, I sprayed the sealing surfaces with carb cleaner to get all oil off of them, then wiped them down with a paper shop towel. No tang, that would have hung on the paper towel. No oil drip this morning. It was just a case of me not getting the RTV good on there last time because of the gas tank being in the way. Jacking the body out of the way made it much easier this time (darn, I wish I had a lift! Oh well!).

I did have to file some tangs on the front once, but that was because of the PITA of prying out the spider gear carrier to put in the Aussie Locker, the hardened pry bars put some burrs on the differential case. I caught it when I did my cleandown, filed them off, and it's been sealed ever since.

-Badtux the Wrenchin' Penguin

Gordon said...

I assume you used oil-resistant gasket-grade RTV?

BadTux said...

Yeppers. Went to the NAPA down the street from the office and told the old guy behind the counter what I needed, he walked to it and handed it to me. It's a pleasure doing business with someone who knows his shit. Not like those toddlers down at AutoDrone, who wouldn't know an RTV from an ATV if you asked them upon penalty of an ass whuppin'.

It's been five days now and not a drop has leaked, so obviously it worked :-).

- Badtux the Leakless Penguin