Hi guys, hoping someone can maybe point me in the right direction here...

A couple months ago I had my drivers side leaf spring break on my 92 Cherokee Laredo. So I bought two new heavy duty leaf springs for my Cherokee as I tow a boat a lot.

Upon installing them, it was obvious my front coil springs were sagging BAD as the rear end was jacked up way higher than the front.

I installed two new heavy duty coil springs in the front and the vehicle now looks as it should.

The problem is, ever since I drove it a few days with the rear end jacked way up, whenever I let off the gas and the suspension "un-loads", I get a grinding noise in the rear end or at least it seems as if it is coming from the rear of the vehicle.

It's a subtle noise, but obviously it shouldn't be doing it at all. I took the cover off the rear end and inspected everything, I seen no metal shavings and the rear end grease looked good, but I replaced the fluid anyway, no change in the grinding noise.

I replaced the rear wheel bearings when I installed the front coil springs, I figured that wasn't what was causing it, but figured it was a good time to replace them as I had access to a lift. It didn't change a thing as I suspected.

The vehicle only has 99,000 miles on it and is rust free, I would like to get a few more years out of it so trying to keep it well maintained.

Any thoughts on what this grinding noise could be? It is the Chrysler 8.25" rear end.

I appreciate your time!

My jeep does the same thing. I was at 4.5" of lift. Now it has sagged to 4" of lift and noise is barely noticeable. How many inches of lift do you have? After I lifted rear of jeep it took out my u joints on rear drive shaft. I replaced them had no vibes and no noise. Now that ive been driving it for awhile it started makeing noise you described (u-joints?). But now that its lower rarely hear it.

I didn't lift my Jeep, they were the OEM spec leaf springs and coil springs for my Jeep that Rock Auto sold. The ones that were on it were the original ones though so were 22 years old and sagged badly.

I will have to check my U-joints, maybe they got hurt when the back end was up so much further than the front.

Shackles look good?

When you raised it back to proper height you also changed the angle the U-joints run at.
If they've got some miles on them they can make noises when that happens.

Yes, they are new.

Did that when I did leaf springs.

They had about 10,000 miles on them before I raised it back up, I am hoping to get them changed this weekend and see what it does.

Thanks guys for all your input, really do appreciate it.

Mine's doing the exact same thing, happened right after my rear lift. Drove it for a week with the "Sport Rake", Cherokee SS style. My u-joints are also relatively new, and I'm hoping that some settling and maybe a transfer case drop in the future will solve the problem. No bad vibes, some around 40mph and 65 mph, but not horrible.

It's got to be the angle in the drivetrain; more exactly, at the slip yoke. I can drive and let my foot off the throttle and here a "GRRuuunnnk" from the rear. I think it's the slip yoke vibrating. that's my thoughts anyways.

Just wanted to thank everyone again for your input, yesterday I swapped out the rear drive shaft u-joints with new ones, the noise is gone...

Turned 100,000 miles on my Jeep this morning, finally it's broken in!