88 240 - grinding noise from rear end Topic is solved

e777 · Post by **e777** » 15 Jul 2021, 17:25

Hi all:

My 88 240 sedan makes a grinding sound from the rear end when driving at 10-15 mph.

The rear brakes are fine (no stuck calipers).

The carrier bearing is new.

My question is this: when the car is in motion and I shift to neutral, the grinding disappears. I shift back to drive and the grinding reappears. Does this mean I can eliminate rear wheel bearings as the culprit and need to focus on the differential?

Thanks!

Post by **volvolugnut** » 15 Jul 2021, 18:44

Safely raise both rear wheels and put the transmission in neutral. Then turn each wheel while holding the other still. This should let you or a helper determine the source of the noise. Be aware that the differential will try to turn the other wheel in the opposite direction if it is not held still.

volvolugnut

e777 · Post by **e777** » 16 Jul 2021, 07:56

OK. Thanks. Will do. I'll let you know what happens....

Post by **BlackBart** » 16 Jul 2021, 11:33

e777 wrote: ↑15 Jul 2021, 17:25...when the car is in motion and I shift to neutral, the grinding disappears. I shift back to drive and the grinding reappears.

This makes me think transmission, not rear end. The diff and driveshaft are still spinning while in motion.

Post by **volvolugnut** » 16 Jul 2021, 12:01

This model should have a electric speed sensor at the rear differential. It has a magnetic pickup to a toothed wheel. If there is crud on the wheel, it might make noise. As BlackBart says, it might be transmission issue sounding like the rear. Getting the rear axle is raised, you should be better able to locate the noise.
volvolugnut

e777 · Post by **e777** » 16 Jul 2021, 12:59

BlackBart wrote: ↑16 Jul 2021, 11:33
e777 wrote: ↑15 Jul 2021, 17:25...when the car is in motion and I shift to neutral, the grinding disappears. I shift back to drive and the grinding reappears.
This makes me think transmission, not rear end. The diff and driveshaft are still spinning while in motion.

Yeah, I really hope it is not the tranny. I will lift the rear and check for the noise. Stay tuned.

e777 · Post by **e777** » 18 Jul 2021, 17:08

I jacked it up yesterday and determined that the tranny is making the grinding noise. I have managed to avoid replacing the tranny on any of my Volvos for a good 15 years, but it was bound to happen. Ironically, this is the youngest of the bunch (190K miles). I have a spare AW70 that I will install...at some point.

Thanks to all who offered assistance with this!