Rumbling noise ? Differential ?

Friday 13th Jimny loaded up and on the road at 7.15am. Destination Walters Arena to help marshal at the AWDC Driven To The Edge. Once onto the A34 noticed a slight noise from drive train. Not a constant wheel bearing starting to fail noise. Rumble increases in pitch then decreases. Difficult to put into words. Drove all the way to Wales, spent 3 days driving around the site then returned home to North Hampshire. The noise is now getting louder. Today I removed the rear prop shaft and replaced it with a spare unit I have. The noise is exactly the same. Is this noise the result of a differential bearing starting to give up ? Topped up diff oil. Was a bit low but still oil in there. Has anyone else ever come across similar. Appreciate your comments on where to look next.

Oh forgot to say my Jimny is a 2000 model with over 100k on the clock. Transfer box oil level was also checked and is fine.

Mine had a noise from the rear diff. Even got a proper mechanic to sit in the back and diagnose it: he said to put some magic potion in and ignore it until it got too noisy to stand. :whistle:

I swapped the diff out and the "new " one had the same noise. :evil:

Some time later I found that the brake pedal had to be pumped to stop the car, when I jacked it up the front passenger wheel was hanging off, so I fitted a new front wheelbearing and all the noise from the rear diff went. :pinch:


Doesn't mean that your diff isn't worn, but worth checking all the wheelbearings first before you swap it.

Disconnected the rear prop shaft at the transfer box. Jacked up front onto axle stands. Started up with front wheels driving. No noise. Still points to rear diff I think !

As you have axle stands use them to support the rear then run car in 2wd in gear and listen with a stethoscope or even a long screwdriver on the diff case and listen for the noise. A bearing growling should be evident.

Yes I did that yesterday. Got a good stethoscope. Trouble is interpreting the noises. Thanks for the idea.