Hi everyone, I just became the owner of a 2008 LR2 and I'm loving it so far. Mileage is a tad high at 150k but everything is working perfectly at the moment. The only concern I have is that when driving at about 10-30 mph I can hear a slight hum coming from the rear. I tried quickly turning left and right to manage the weight and rule out a rear hub bearing. The noise seems to remain consistent which makes me think it may be the rear differential. Does anyone know if there is an easier way to tell? Any signs I should look for? I'll probably do a rear diff oil change just to be safe but wanted to get opinions first.

Thank you!

 

My local mechanics put the car on the lift and used stethoscopes. This ruled out the wheel bearings. In my case it was the rear differential bearings.

 

If you put a strong magnet on the outside of the fill bolt it will collect the steel from the bearing.

You can remove the magnet and bolt and wipe off the black dust.


more information. https://www.freel2.com/forum/topic29861.html

https://www.freel2.com/forum/topic14659-30.html


How loud is the noise? Can you hear it with the radio playing or if people are talking? Or do you have to be quiet and listen carefully?

I could hear mine if I shut off the radio and no talking at 50,000 miles

By collecting the steel dust and upgrading the gear oil mine is silent at 120,000 miles

Note: I’ve shared this with others and new oil and a magnet isn’t enough for a very loud bearing

good luck

Paul

 

Better pictures that show how much steel dust the magnet collects.

https://www.freel2.com/forum/topic34...ghlight=pinion

 

You cant hear it when the radio is on but you can hear it otherwise. Its not too loud since at first I thought maybe it was just tire road noise. I'll take a look at those links. Thank you!

 

Summary of what I wrote this on the other forum.

My Pinion bearing History

Summary of what I did for my LR2 (Freelander 2)


http://www.freel2.com/forum/topic14659-15.html

For reference (approximate mileage)

40,000 miles I first hear the noise of the bearing the dealer indicates that they can't duplicate the problem
50,000 miles warranty ends, I change the fluid in the differential (the old fluid is full of small air bubbles, it should have been changed sooner)
55,000 miles I place a strong magnet on the fill bolt of the differential (some magnetic particles are attracted to the bolt)
80,000 miles switch to a drain plug with the magnet built in (clean periodically to remove magnetic particles)
90,000 miles the drain plug magnet is nearly free of magnetic particles
110,000 miles the pinion bearing is silent and the magnet is not collecting much magnetic dust


It appears that the changes that I made did extend the life of my pinion bearing.

Note: I didn't fix it I just made it wear out more slowly.


Two significant changes were made to extend the bearing life

1. Magnetized the fill bolt for the differential (to collect the magnetic dust and prevent it from doing more damage)

2. Switched to a synthetic fluid for the gear oil and I had to special order it because it is intended for use in heavy trucks and mining equipment (it wasn't expensive, it was just difficult to find)


The gear oil Note: this is not the Mobil 1 LS that you can buy at autozone (I had to order it)

This is the right stuff https://www.summitracing.com/parts/m...BoCw3EQAvD_BwE

Mobil Delvac 1 Gear Oil 75W90


I chose this gear oil based on several different criteria

1. Application information from Mobil indicates that "....extreme pressures and shock loading are expected"

2. Mercedes specified it for use in the differential of the sprinter Van "MB-Approval 235.8"

3. Its a synthetic gear oil which should help with low temperature performance


Good Luck

Paul

PS One more link

https://www.freel2.com/forum/topic30...+things+happen

From that link

As for what it sounds like?

The sound is like cutting steel on a Lathe, not an aggressive cut more of a finishing cut, if you know what that sounds like.


I agree with the others that wheel bearing sound very similar to the pinion bearing.


To determine if the pinion bearing is the source of the noise just buy a drain plug with a magnet. (Or attach a large magnet to the outside of the drain plug)

If the magnet collects some fine black dust then it is likely the bearing.

To be certain that it is the bearing remove the drain plug every week and wipe it off to confirm that you are still collecting black dust.

After about 8 or 10 weeks one of twothings will happen.

1. The amount of black dust will get worse and the noise will get louder and you will become friends with Austin at Bell Engineering (A company in the UK that specializes in rebuilding the pinion bearing)

2. The amount of black dust will become less and less and the noise may disappear or if it remains then you should look at the wheel bearings.

If you are lucky enough to get option #2 then you should change the gear oil and continue to monitor the magnet and the noise to see if the pinion bearing fails.

In my case I was lucky and I got option #2; its been 70,000 (Edit: 80,000 now) miles since I first heard the noise.

 

For future reference, @p_gill , what are the specs for the diff drain plugs, PTU and rear? Or, where did you purchase your magnetized drain plugs?

 

I still need to get a magnet for the power transfer unit.

I will need to measure the size of the bolt and the pitch of the thread.

Note: ESC sells a power transfer unit seal kit that includes the drain/fill plug and its the same number as the rear diff (I will try swapping my dimple from rear to front)

As for the rear differential

I bought a drain plug made by Dimple


I didn't buy it from ECS but I am reasonably certain that this is the same part https://www.ecstuning.com/b-dimple-p...ssm18x1.5~dmp/

or this part M18X1.5X12 direct from Dimple

https://drainplugmagnets.com/cars/volvo/


Here is the size information


M18X1.5X12

VOLVO MANUAL TRANSMISSION, FILL AND DRAIN PLUG

REAR DIFFERENTIAL, FILL AND DRAIN PLUG

If you look at the description

M18 (is the size of the bolt 18 mm)

1.5 is the the thread pitch in mm

12 is the length (not counting the head)

 

Thank you for the good info!

 

I believe my rear differential is bad too.

At about 40mph the sound becomes noticeable and doesn’t change if i coast or decelerate. Goes away with “increasing rpm” super loud even over the radio. I have some traction control issues and some rough shifts in 3&4th gear (when the noise starts).... on highways going a comfortable 70 🤣 it is still heard and will bust your ear drums if you don’t crack a window. I’m not familiar with the foreign nature of the rear diff but I have wondered if a gear as well as bearing could be causing backlash thus thinking on rough or delayed shifts