Differential grinding...and I thinking this through correctly?

[Cottontail]

Looking at buying a 5.9 Grand Cherokee with "grinding in the front differential" per the seller.

The 5.9 came with quadratech, the full time 4wd. In this case, if I pulled the front drive shaft to drive it home, that won't stop the grinding would it? Actually, with a full time 4wd, could I drive it without a front drive shaft? Gears are turning in a front differential all the time, correct?

It's only a 10 mile drive, so I may be able just to grit my teeth and listen to it grind...

He's selling it cheap due to quotes between $900-$1300 he's gotten to fix it. I could do it with a junk yard axle for about $150 and some time. Thinking I could make a quick profit on this one!

Thoughts?

 

[Phil]

Got any friends with tow rigs and trailers? AAA?

If it doesn't have part time 4x4 or 2WD you'll need that front driveline installed.

 

[5-90]

FT4WD is usually differentiated, pulling the front shaft will usually mean that the differential sees the front wheels "slipping," and shunt torque to them.

You'll need PT4WD or 2WD to drive home and move - if you're in FT4WD, you probably won't move.

Also, pulling the front DS may not stop the grinding - it really depends on why it's grinding. If it's the front output bearing, it will probably shut up once you unload it. If it's a bearing in the axle, it may or may not shut up (a wheel bearing won't shut up, a carrier bearing has about a 50/50 shot at quieting down, and a pinion bearing will usually quiet down if it's unloaded.

However, since most of the bearings in the front axle have dedicated inner races (unlike the C-clip rear shafts, that run directly on the shaft,) you probably won't damage anything driving it home a short distance.

YMMV.

 

[pityocamptes]

Had a friend that that happened to. He basically never filled the diff with oil - was leaking and the diff made a nasty grinding noise. Pulled the front DS and he drove it forever and a day like that. It looked like the pinion bearing went south/possibly the carrier bearings as well, he just never had time to repair it and it was basically a DD.

 

[Cottontail]

Had a friend that that happened to. He basically never filled the diff with oil - was leaking and the diff made a nasty grinding noise. Pulled the front DS and he drove it forever and a day like that. It looked like the pinion bearing went south/possibly the carrier bearings as well, he just never had time to repair it and it was basically a DD.

And this was on a Jeep with full time 4WD???

 

[Phil]

And this was on a Jeep with full time 4WD???

Doubtful.

 

[pityocamptes]

It was on a Jeep Cherokee, not sure of the year but older model. I also believed it had 4wd full time as when we removed the DS the output yoke on the TC was still moving. Indicated it may not last that long but he seemed to drive it all over the place including out of town.

 

[1990JEEPXJ]

like said. if it has AWD, it wont move without the front driveshaft. same with full time 4WD on XJs

 

[Ghost]

Could he pull the shafts and put stubs in the wheelbearings? I thought those systems used a viscus clutch?

 

[Cottontail]

I went and looked at it. The drive shaft was in the rear of the Jeep and I drove it at 55 MPH with the grinding with no issues.

The Jeep had a bunch of nickel and dime issues though...falling headliner, broken tailgate latch, chipping paint (and had been repainted), a CEL for a vacuum leak.

I decided to pass for now. We'll see if it is still for sale in another couple weeks!

Maybe I get the Jeep, pull the 5.9 to put into my '96 ZJ, put those plush leather seats into my XJ, and then use the hood vents on the XJ also!!!