SwedeSpeed - Volvo Performance Forum banner

1 - 3 of 3 Posts

·
Registered
Joined
·
1 Posts
Discussion Starter · #1 ·
I'm new to this forum and appreciate any insight on my issue.

Just replaced the rear differential on my 2008 XC90 (140,000 miles)with a used one. I used a well regarded local Independent shop rather than have a new one installed at the dealer. Got the car back yesterday and the differential seems fine.

Here is my issue: The front end is now totally unstable. It seems to be swaying and driving over a bump feels like the car is going out of control. I brought the car back to the shop and the owner says that it would be totally unrelated. He did say before I picked up the car that the front felt like it had a mind of its own, and thought I may need new struts. I told him that I had not experienced the problem before.

Would anyone know if replacing the rear differential could have such an effect on the front end?

Thanks!
 

·
Registered
2008 XC90 3.2
Joined
·
1,297 Posts
It is quite possible it is both where there was an issue before the work and the work contributed to it.

First the issue before. You could have worn out front end suspension components at your mileage. The main issue would be the control arm bushings that have to be replaced on ALL XC90s due to normal wear. This could throw off alignment on a bump. Other components, like the front balljoints, is another part that gets worn out and should be replaced with the control arm bushings.

In addition, the rear could be out of alignment if the shop had to unbolt any suspension components to gain enough access in replacing the rear differential. This would throw off the alignment specs and cause what is known as a "rear" steering issue. That could contribute to the sway (or loose feeling), especially if you have worn front end components. I do have to ask, did you get the differential filled with synthetic fluid and the Haldex fluid/filter changed while at the shop? This should be done to ensure it stays trouble free.

So, the shop probably had to do what they had to do to fix the rear differential, but I do not believe they intentionally did anything wrong. This would probably be a good time to get the front control arm bushings and balljoints done because that work will need an alignment too. With good maintenance, you could be on your way to reaching 200k miles.
 

·
Registered
Joined
·
534 Posts
When our car was still on warranty a lower control arm rear bushing came loose. With hands off the steering wheel it would cross lanes in less than 3 seconds.

To see if the rear diff alignment is off check to see that the car is not dog tracking by observing from behind as someone drives in a straight line.

If something happened since the differential change maybe the AWD is always engaged and driving the car? I am just guessing here and don't know much about when they are supposed to be engaged or not other than front wheel slippage supposedly triggers it.
 
1 - 3 of 3 Posts
Top