'Bumping' when turning corners slowly - L322 Range Rover

Hi guys

Hoping you can help us out.

I own a 2004 L322 4.4 petrol, 54k miles.

Recently it has started making a 'bumping' noise (more of a sensation than a noise) when turning corners slowly, and it worses the harder you steer.

To me, it seems like a diff issue? It's not knocking like you would get with anti-roll bars links etc but more of a quick 'on off' bumping sensation/noise.

The car has had the diff recall done before I bought it (you can see it's pretty new as it's gleaming compared to the rest of the underside).

So, I'm thinking maybe try changing the diff oil (the car has three diffs apparently)??

I asked Land Rover and they said there is no interval listed for change of diff oil as it's not a part of any standard service. But, I assume it would have a 'life' of some sort otherwise you could have a car with 250,000 miles running on the same diff oil?

Any suggestions, help and questions very welcome!

Please help!

many thanks!

Lion Heart

Possibly CV joint problem. Inspect the boots to see if they cracked or torn, often the precursor to a bad CV unit as water and grunge get in.

I had this on another car - not a RR. It was tracking out on one side. Due to tyres wearing the tracking was no longer perfectly aligned on both sides. So what was happening was one front wheel was turning slightly out of alignment with the other, hence the bumping. Best to get this checked first before worrying about diff's etc.

Hi there

Ah yes - that's a good point! If the tracking is out I guess that could make the diff start to struggle as the loads are no longer even between sides.

Makes a lot of sense!

I think I'll get it booked in for a full four wheel alignment!

Fingers crossed!!!

Lion Heart

im baffled? how can tracking be wrong on one side only?

Hi there

Well, I'm no expert, but there are track rods on both sides and each is subject to different forces during driving, cornering and so forth. When you get your wheels tracked/aligned it's VERY rare that both sides are out by the same amount. I've had tracking done on previous cars probably 5-6 times total and it's amazing the difference between wheels.

Any one agree/disagree??

Lion Heart

What a load of balls tracking out at one side. Ackerman angles always make inner wheel turn more than outer one. If you have silly wheels and tyres the inner tyre maybe catching the body. If so have the steering stops adjusted. Or of course it may just be a CV joint on it's way home.

Well it may be co-incidence, but when my tyres were worn I got this bumping, particularly on full lock. It was as though the wheels were not exactly in alignment. In fact the tracking was also out a little, maybe I had run up a kerb as well I don't know, anyway it made a difference to the bumping on full lock.
But I should add it was never perfect until I got new tyres and then the problem disappeared completely. But - it wasn't a Range Rover it was a Z4

Yes, the wheels must turn at different angles, 100% correct. The tracking is adjusted by the track rods, and these do go out of alignment over time (otherwise you'd never need to get tracking or wheel alignment done). And so I think (although someone else please feel free to comment!!!) it's absolutely possible that the tracking can be different between wheels.

Lion Heart

nisbeam said:

Well it may be co-incidence, but when my tyres were worn I got this bumping, particularly on full lock. It was as though the wheels were not exactly in alignment. In fact the tracking was also out a little, maybe I had run up a kerb as well I don't know, anyway it made a difference to the bumping on full lock.
But I should add it was never perfect until I got new tyres and then the problem disappeared completely. But - it wasn't a Range Rover it was a Z4

Click to expand...

The wheels are never in alignment on full lock, take a look, the inner wheel turns in more than the outer one. Ackerman angles do this because the inner wheel is describing a smaller arch.

Yes that is correct, but the diff transfers power to the wheels based on those angles being correct. So if one wheel is mis-aligned before steering it will still be misaligned when steering and so the diff will start to struggle.

In theory at least.

So yes, wheels are at different angles when turning. BUT if one wheel is 1 degree out of alignment (for example!) then it will also be 1 degree out when the wheel is turned.

Lion Heart

Lion Heart said:

Yes, the wheels must turn at different angles, 100% correct. The tracking is adjusted by the track rods, and these do go out of alignment over time (otherwise you'd never need to get tracking or wheel alignment done). And so I think (although someone else please feel free to comment!!!) it's absolutely possible that the tracking can be different between wheels.

Lion Heart

Click to expand...

Tracking is about wheel alignment in the straight ahead position. Either parallel to toe out or parallel to toe in. Driven wheels toe out, undriven wheels toe in. The tracking only needs to be very slightly out to wear the tyres in dramatic fashion. The tracking cannot be out at one side on a P38 because the track rod only has one adjustable end and the castor angle will make the wheels track true even if the track is out. That is what wears the tyres. It is possible on a vehicle fitted with rack and pinion steering gear (think the L322 has this) to have more travel at one side than the other, but the mechanic would have had to have seriously ****ed up if that was the case, the tracking (toe in or out could still be correct). He would have to have set track without having steering wheel in straight ahead position then moved steering wheel to suit. Bad practice if that is so. It could be that a kerb has been struck and bent something in which case it needs checking. If this is the case the steering wheel should be sitting off centre when vehicle is being driven straight ahead. The diff won't struggle that's balloney.

So if the diff does not struggle when under uneven load, what would cause the bumping noise/sensation when turning corners at slow speed?

It gets worse the harder the steering is locked over.

Also, wheel alignment is probably different from tracking. Wheel alignment measures the wheel at lock as well as straight, which is why the front wheels go on to turntables and the rears on to plates to allow lateral movement for angle adjustment.

Lion Heart

Lion Heart said:

So if the diff does not struggle when under uneven load, what would cause the bumping noise/sensation when turning corners at slow speed?

It gets worse the harder the steering is locked over.

Also, wheel alignment is probably different from tracking. Wheel alignment measures the wheel at lock as well as straight, which is why the front wheels go on to turntables and the rears on to plates to allow lateral movement for angle adjustment.

Lion Heart

Click to expand...

As said before it maybe a CV joint. It maybe a siezed viscous coupling in which case diff would be struggling. Tracking is set with wheels in straight ahead position. Steering geometry is a lot more complexed than tracking and is checked by placing degree plates under the front wheels and turning them on lock. Each wheel on each lock should move in a preset relationship to the other. These are known as the Ackerman angles. The inner wheel turns in more than the outer one the difference in angle movement becoming greater as more lock is applied. If tracking is correct a mismatch on the published Ackerman angles would indicate a bent steering arm.