Front diff pinion seal replacement

[ophidia]

My '99 Mtneer 4.0L 4WD is dripping fairly steadily from the pinion seal on the front differential. I was thinking of taclking this myself. What's all involved with this job? Is there a how-to somewhere? I've had both driveshafts off before to replace u-joints, so removing it won't be a problem. Also, is it possible to get to the fill plug on it to check/top off fluid without dropping the pumpkin? It looks like it's stuffed in there pretty well.

Thanks!

 

[imp]

My '99 Mtneer 4.0L 4WD is dripping fairly steadily from the pinion seal on the front differential. I was thinking of taclking this myself. What's all involved with this job? Is there a how-to somewhere? I've had both driveshafts off before to replace u-joints, so removing it won't be a problem. Also, is it possible to get to the fill plug on it to check/top off fluid without dropping the pumpkin? It looks like it's stuffed in there pretty well.

Thanks!

First, be sure it's the seal that's leaking, not the gasket up front. Wipe it down and run awhile, check that the leak is where you think it is.

Most IMPORTANT thing about pinion seal replacement: Get the pinion bearing preload back in the correct ballpark. The flange nut must be TIGHT when the correct preload is present. If tightening the hell out of the nut does NOT restore adequate preload, you are toying with gear failure at worst, or gear noise at best, if the pinion's location with respect to the ring gear is able to change due to bearing looseness.

Search out one or two of the threads relating to pinion seal replacement, and study them closely. A good shop manual would help greatly, too. imp

 

[RomeovilleIL]

Also, is it possible to get to the fill plug on it to check/top off fluid without dropping the pumpkin? It looks like it's stuffed in there pretty well.

The fill plug isn't too difficult to reach if you go through the drivers wheel well with an extension. It's a 3/8" square that matches up with the socket extension. You can suck out the old fluid and refill from there with some flexible hose. Completely forget about trying to get a lube bottle even close to that fill hole.

 

[ophidia]

Oh, you get to it from the side and not the front cover? That'll be better. I picked up a gear lube pump tonight, and I'll probably top it off tomorrow. Can't have it running dry and toasting itself before I get this fixed.

 

[drdoom]

Just fit a 2 foot length of rubber hose onto the oil bottle, then you squeeze the oil in.