Rear differential clunk

[gonzalo4to]

Hi. There is a loud clunk in my rear diff, much like the sound of two hammers hitting each other, or like a bell.

It usually happens on 1st gear, during takeoff, but not necessarily when the gears mesh. Sometimes it happens on 2nd gear after applying power, when going real slow. The clunk happens after 1/8 or 1/16th of the driveshaft rotation, just after takeoff. So it is NOT at the moment of taking torque, it is a millisecond after that. Hard to explain. The car is basically already rolling for a split second before the clunk happens, so I think it is not gearset backlash.

Also, I "measured" the backlash while the car was on the ground, with both transmission and transfer in NEUTRAL, and it was fine. Less than half cm. It did not seem excessive.

What could it be? Any help is appreciated.

[gonzalo4to]

Forgot to specify.
1998 Mitsubishi Montero II LWB (Pajero)
Leafspring suspension in the rear
2.8D (4M40) N/A
Manual, V5M21 transmission, non-Super Select.
Brand-new U-joints

Thanks in advance.

[AndyNH91]

I had similar symptoms in a Daihatsu Rocky. It turned out to be a prop shaft CV starting to seize. I had it checked out by a mechanic who blamed it on a leaf spring. A couple of weeks later the front cv on the rear tailshaft let go at 80km/hr, with the whole propshaft bouncing between the bitumen and the car floor until I could bring it to a stop. Lucky the shaft didn't stick into the ground otherwise I might have landed on my lid.

Anyway, perhaps something to check out with the car on jack stands on the transfer case in neutral. Does the rear propshaft turn smoothly?

Sorry just read that you have new U joints, probably not your problem in that case. Missing tooth off the crown wheel or pinon?

[old Jack]

Rear brakes and or hand brake not releasing completely ?????

OJ.

[gonzalo4to]

Rear brakes and or hand brake not releasing completely ?????

OJ.

No, that's not it. I've had it for a while now, and I've learn to live with it... It's coming from the differential. I have decided that I will get an airlocker sometime this year, so when I have the diff off the truck, I might as well take care of that problem, *whatever it might be*...

thanks for the tip though!!