What I thought sounded like a wheel bearing turned out to be coming from my front diff on the ZJ. The sound has been getting worse and worse; been running in 2wd but in 4 all time it's unbearably loud. It sounds like some sort of bearing problem, just a loud grinding from 20-30 mph and then a loud groan any faster.
I took the fill plug out to see if perhaps it was low on oil. Instead, a thick sludgy black/greenish oil oozed out. I changed the oil and gaskets a few months ago, so obviously something's wrong.
Any ideas? It's winter here so almost no chance of doing any work myself. Are we talking a rebuild here?
That would be my best guess.If you pull the front cover - you'll know for sure. It could possibly be the front carrier and pinion bearings but from your description,it's probably too far gone already.......
sorry for hijacking your thread but when i put my jeep in 4wd since i rotated my tires i have developed a humm could this just be my tires or do i have a front diff problem also? I had a free tire rotation at a tire shop so i don't know how they rotated them.
Well, I would imagine if your diff oil is fine and you're not hearing any groaning or grinding, you're probably fine and it's just your tires.
Anybody know how much it costs to get a shop to redo the bearings in a diff? I've read that a rebuild is close to 800$; with the Junkyards all pretty much closed (average temp is like 8-10 Fahrenheit these days) I don't know how I'd find an axle used.
At this point it's becoming a chore to keep the ZJ running well. I'm spending well over 250$ a month on parts alone, and there is tons left to do... Considering just selling the thing, although I love it, and buying a newer cheap 2wd Ranger...
I called a local transmission/diff shop. The guy said without having a look yet a rebuild can go anywhere from $500 to $1200.
I'm going to shop around.
Anybody know if just changing the bearings would help, even if the gears are slightly worn since all this?
Changing bearings won't do much good because with what you've described there probably isn't much left in the way of gears. Pull the front cover. You'll know what you need to do. If the gears look good and there's no teeth missing,then maybe bearings would take care of it. You could have something wrong with the front carrier too.
Pretty sure the bearings are just toast in the diff.
If it changes anything, there seems to be little to no play in the front DS. The noise is also not a high pitch squeal indicative of a pinion bearing but more of a hum/rumble/groan, kind of like a bad wheel bearing.
My real question is, if my 4x4 is working like it should now even with the bad bearings, and I DO happen to find some metal shavings in the oil, is it completely necessary to change the gears? Or will replacing the bearings suffice?
It depends on what the gears look like..... I'm assuming it's an open front diff. If that's the case,you might have something going on with the spider gears in the carrier. The longer you run it the way it is,the more damage you will do....