Rear Diff issue- rasping noise

[BreakingTrails]

Apoligies in advance for my terrible verbiage.

My 98 defender 110 is having an issue with the rear diff. When its pulling it sounds just great, but if I release the accelerator or she starts rolling down hill there's a vibrating/rasping noise which lasts for a second or two as the diff 'loses torque'. Once decelerating the noise goes away. The same occurs once I start to accelerate again.

Tomorrow I'm heading to a specialist but I want to arrive armed with some knowledge.

My questions are-
1. What is the cause of the noise
2. What are potential solutions
3. Am I damaging the diff by driving it in this state (there is another, highly recommended specialist around 300km from me in the direction I'm heading)

Cheers!

Sent from my SM-G950U1 using Tapatalk

 

[WOODY2]

Are you sure it's the dif and not U joints?

 

[gatorgrizz27]

It does sound like a pinion bearing going out, look under the truck where the rear driveshaft connects to the diff and try to wiggle it. There should be zero play that isn’t rotational.

Good news is rover diffs are extremely easy to swap out, and they were all the same front and rear as well as gear ratio in the RRC’s, D1’s, and to my knowledge the Defenders as well except some 130’s that had Salisbury rear axles.

If it does need a diff rebuild, I’d be tempted to just swap a lower mileage one in if it can still be found. Setting up diffs correctly is tricky and they can seem fine for awhile but wear out quickly. If you have aftermarket gears or lockers rebuilding yours is the way to go though.

As far as it being safe to drive, generally they will last quite some time with a bad pinion bearing, but will get noticeably worse. Make
Sure there is still enough fluid in it though.

If you want to check it for sure you can pull the rear axle shafts and driveline, lock the CDL, and take a quick spin. I bought I D1 that had a blown rear diff and wouldn’t move without lurching and crunching noises. Did that and drove it home, swapped in a $150 used diff from eBay.

 

[Red90]

It is not a Rover diff. It will be a Salisbury.

Don’t jump to any conclusions. It could be many things.

 

[gatorgrizz27]

It is not a Rover diff. It will be a Salisbury.

Don’t jump to any conclusions. It could be many things.

Yeah, lots of stuff can make weird noises, but the growling when coasting is the #1 indicator of a bad pinion bearing. Not that it couldn’t be something else. Does look like you’re right about the diff design and will be a rebuild rather than a swap if that’s what’s wrong with it. Also looks like they might be a semi floating design which is weird given that they are supposed to be the heavy duty option

OP, go wiggle it and report back.

 

[Red90]

It is not a semi float design. It is full floating.

There are lots of possible things it could be other than pinion bearings. That would last on my list of possible causes.

 

[sturgillk]

Mine's a '97 Disco, and when I first lifted it I was getting the same noise in the same conditions. Turned out to be my front driveshaft, geometry had changed enough to make it grind in "neutral float".

I put in a double cardan front driveshaft and the sound went away completely. I've also seen posts from people who have just learned to live with it.

Anyway, might be what you've got going on.