Hi there, posting this here to get help

I have a noise coming from the rear that only appears when coasting - I recorded a video, hopefully people can hear it well:


Things I have already did myself:

- replaced front driveshaft with new one
- replaced rear driveshaft ujoints
- greased everything
- replaced rear left wheelhub

I then took the vehicle to a local so called "Land Rover specialist" mechanic - he removed the rear differential and said that his "visual inspection" did not detect anything unusual (but I don't think he knows how to inspect with proper gear marking compound for instance).

Does anybody have tips (or have suggestions) or what I should investigate next?

Thanks!

 

What year is your discovery? You might have center difflock…if so, you can remove the rear drive shaft and put the TC in lock to find out if the noise changes.

 

2004 V8

Ok thanks - will that rule out any problems on the rear differential?

And can I try this also with the front one?

Thanks!

 

Sounds like rear differential, my best guess would be pinion bearings are worn, which would make noise because it changes the angle of pinion, and allows ring and pinion blacklash gap to be excessive.Find a good used one or have thay one rebuilt...but not by the guy that did a visual...whatever the heck that is. You need a dial indicator and a few other items to check preload and pinion/ringgear tooth alingment/depth.

 

Thanks!

 

I agree with The Deputy. My 2011 Suburban needed new rear diff bearings and sounded just like that, and it was on coast (at first).

 

Thanks!

When you guys say rear diff bearings, for my case, Disco 2 2004, will that be number 7 on this diagram?

https://www.roversnorth.com/category...i_differential

 

That is the pinion bearing. And that is likely the bearing that is worn enough to cause this noise since it is only on coast when the pinion load shifts.

But....

Get a rebuild kit with all new bearings if you are going to do this yourself. You can't just replace that bearing. There is a crush sleeve in there that is one time use, and you will need to replace seals. And the other bearings have been running in oil that has been contaminated with the bearing material from the failing bearing, so they will exhibit greater wear too. Atlantic British has a kit for $220 plus tax/shipping. Also, you will need to inspect the pinion. It shoud be fine, but it is possible it may have worn and need replaced. And, if you have ever thought about getting a locking diff, now would be the time, especially if you are not comfortable with doing this work yourself. You can get a third member ready to go for around $1400, and then it is just a simple swap (or as simple as a part that heavy gets).

 

Thanks - yep, probably going to do that, buy a new one. But I am trying to figure out if it is indeed from the differential (or only the wheel bearings).

Mine is 2004 - it is the one with CDL (sorry I am new to this but that is what you mean when you said "locking diff" right?)

 

Nope.

Not sure how new you are, but I am going to go "deep" here. If this is review of knowledge you have, please understand I don't mean to talk down to you.

A differential in an this context is a device which allows two different outputs that share a common input to operate at different rotational speeds - a differential of speed. The Discovery 2 has three differentials to support it's full time 4WD system: One in the transfer case to allow front and rear axles to operate at different speeds, and one in each axle so the right and left wheels can operate at different speeds. These speed differences are not huge and are created most commonly by cornering. The differential prevents drive train stress and binding and wheel scrub when those small differences in speed occur, at the cost of sometimes sending all or most of the torque to a wheel or axle with no traction (as anyone who has been stuck in Alabama knows - My Cousin Vinny).

Your center locking differential locks the front and rear output together at the transfer case, ensuring torque is evenly distributed to the front and rear. It effectively locks out one that center differential, but that is only one of three differentials in your drivetrain. If you have one front tire and one rear tire without traction those two tires will still get all the torque, leaving you spinning your wheels (until the traction control senses the issue and intervenes).

You can also get differential lockers for the front and rear axles. Most "hardcore" off-roading vehicles will have them. If you are replacing the rear third member (the part of the axle with the pinion and differential) you can choose to upgrade it to one with a locking differential option similar to your center diff lock. When engaged it would divide torque evenly in the rear between the left and right tires.

Axle differential come in four basic types: Open (what you have now), limited slip, auto-locking, and select-able locking (similar to your center locking diff). Each one has it's benefits and drawbacks.

From places like Lucky8 you can get a third member with all new components in the cast housing with limited slip (Eaton TrueTrac), auto-locking (Eaton Detroit) or select-able locking (Ashcroft or ARB air actuated lock). If you don't do serious off-roading, then there is no reason to consider an upgrade.

Finally, I am no authority on this, so your own research and validation is required.