Help Me diagnose/fix my front diff!

[bemerritt]

Well I think I have torched my front diff. Not sure how, but could use some help with what to do next.

Had noticed some noise, but wasn't bad, thought it was just a squeaky suspension at first. Then, many miles later, it got worse and seemed almost like a cv, but definitely was going with the revolutions of the tire.

Lifted up the tire (driver) and tried to spin it freely and could maybe go 1/8th of a turn but then would lock up. Same on the passenger side.

Dropped the skids and there was quite a bit of oil on the plate and the diff housing. Maybe from the arb air locker hose?

Would love to know what you guys would do next. Seems like in an ideal situation I'd pull out the front diff and take it somewhere, however I seem to remember it's no easy job.

Side note, and not sure its it is related, but the rcv boot on that side is also collapsed, but pretty sure its been that way for the 20k miles its been installed.

Thanks!

 

[tbisaacs]

Not turning with wheels on the ground is normal, it’s all wheel drive.

Before you panic I’d check your diff breather and locker line. If that breather gets clogged the diff gets pressurized and has to go somewhere.

I’d also drain the fluid and strain it and look for sparkles and chunks.

 

[Sandroad]

What’s going on with the hose fitting in the last photo? It looks like it’s damaged and with oil all around it?

 

[bemerritt]

Not turning with wheels on the ground is normal, it’s all wheel drive.

Before you panic I’d check your diff breather and locker line. If that breather gets clogged the diff gets pressurized and has to go somewhere.

I’d also drain the fluid and strain it and look for sparkles and chunks

Not turning with wheels on the ground is normal, it’s all wheel drive.

Before you panic I’d check your diff breather and locker line. If that breather gets clogged the diff gets pressurized and has to go somewhere.

I’d also drain the fluid and strain it and look for sparkles and chunks.

Am I going crazy? Open diff with one wheel off the ground, that wheel should spin, no?

Should have mentioned, drained the fluid and other than there seemingly being less than what I feel like is the full amount, it didn’t look as sparkly as I expected. Maybe a little grey, I’ll pour it into a clear glass from my container tomorrow and inspect closer.

 

[tbisaacs]

Am I going crazy? Open diff with one wheel off the ground, that wheel should spin, no?

Should have mentioned, drained the fluid and other than there seemingly being less than what I feel like is the full amount, it didn’t look as sparkly as I expected. Maybe a little grey, I’ll pour it into a clear glass from my container tomorrow and inspect closer.

It won’t spin.

If you aren’t seeing chunks, fill it back up and make sure your breather isn’t clogged and drive it

 

[KLF]

Am I going crazy? Open diff with one wheel off the ground, that wheel should spin, no?

That would only work if the front driveshaft was free to spin in the transfer case, but it's not in your case, as these are AWD.

If you lift BOTH front wheels off the ground, I believe you should be able to spin a wheel (assuming your ARB is unlocked), but the opposite side will spin backwards. Try this.

 

[Artie]

Am I going crazy? Open diff with one wheel off the ground, that wheel should spin, no?

Are you in park or neutral? In neutral with nothing locked the one wheel off the ground should spin, this is how I orient my zerks to grease them.

You mentioned an air locker, if it’s on the front differential I’d be checking the breather tube. I had a similar situation on my rear differential where the breather tube wasn’t up to snuff so the diff was breathing through the air locker air tube and it pushed gear oil out of the manifold at my compressor. I ended up adding the ARB locker breather thing and the ARB check valve and I’ve not had the issue since. A small gear oil leak through that manifold will look a lot worse than it actually is. As for the noises you’re hearing…. A video would be helpful.

 

[bemerritt]

Oh man, thanks for mentioning neutral, now I feel like an idiot haha. Certainly has been a while since I've worked on the 200.

Spins in neutral, locks with the locker on, and a whole bunch of oil all the way up on the locker air tube/solenoid.

Breather connector had some resistance when blowing on it, but not totally clogged. But did seem like enough resistance that it could have forced the oil to find a path of lower resistance. No resistance blowing into the tube into the diff. Time to fill it up with oil and see if that solves the problem I was chasing. Although I can't imagine driving extensive highway miles was good for the diff with low oil.....

Thanks!

 

[Artie]

Oh man, thanks for mentioning neutral, now I feel like an idiot haha. Certainly has been a while since I've worked on the 200.

Spins in neutral, locks with the locker on, and a whole bunch of oil all the way up on the locker air tube/solenoid.

Breather connector had some resistance when blowing on it, but not totally clogged. But did seem like enough resistance that it could have forced the oil to find a path of lower resistance. No resistance blowing into the tube into the diff. Time to fill it up with oil and see if that solves the problem I was chasing. Although I can't imagine driving extensive highway miles was good for the diff with low oil..... View attachment 4082683View attachment 4082682View attachment 4082681Thanks!

How low do you think it was? There’s 2 quarts in there so maybe you didn’t lose too much… it’s so thick that a little can cover a lot of real estate and look like a lot.

Since you managed to get that breather top off I’d spend the coin and install the ARB diff breather kit just to be safe.

 

[Godwin]

Since you managed to get that breather top off I’d spend the coin and install the ARB diff breather kit just to be safe.

Or save a few dollars and do the same thing with a few feet of vacuum or fuel line plus a small fuel filter and run the breather line up to the firewall.