Grinding front differential

[wranglerdude]

I test drove a 2008 wrangler yesterday. It was fine except when I put it in 4 wheel drive there was a steady grinding sound coming from the front differential. Anyone have any idea what this could be? I would like to buy the jeep if it's not a major issue.

 

[TerryMason]

It could be several things, including the ujoints in the front driveshaft. If the gears are trashed in the front axle it could get expensive (although most people would probably drop a locker in by that point).

Has anything been modified inside the axle (i.e. a locker added)?
Have they ever taken it offroad?

And finally, did the 4wd work?

 

[wranglerdude]

Thanks, I will find out. do you think it could also be the transfer case?

 

[TerryMason]

It could be the transfer case, driveshaft, differential. I'm sure there are other options that I'm not thinking about. How loud is the sound? Could you hear it with the windows up? Can you tell if the sound comes from the front or middle of the Jeep?

If you're planning on putting in a full locker in the front then I would likely take the gamble, and just try and get the seller to knock off a grand from the price. If you're lucky then it's just low on fluid, but if you need new gears in the front, and you need someone else to install them then it could be a thousand or two.

 

[jfrabat]

If the sound changes with speed, it could be the ring and pinion or the TC or the U-Joints...

 

[steady.foot]

Is this from a dealer or a private seller? If it's from a dealer tell them to fix it before you sign on the bottom line. If from a private seller, Assume the worst, Figure how much it will cost to fix and deduct it from the asking price.