'98 XJ - Rear Suspension Thump
#16
CF Veteran
#18
Member
Thread Starter
#20
Seasoned Member
What is the condition of your rear bump stops? Do you have full rubber on both of them?
#21
Member
Thread Starter
Sorry for the slow response. My other Jeep has been playing up, so I've not had time to look at this!
The rear bump stops are in like new condition. They're actually taller than the originals, so I have considered trimming them down.
My first suspicion was that I might be hitting the bump stops frequently, as that's exactly how it sounds. I tested by putting some butyl rubber (like putty) on the bump stops to see if it got squished. After normal driving around (with the noise present) the putty didn't get squished, so I don't think I'm hitting the bump stops.
The rear bump stops are in like new condition. They're actually taller than the originals, so I have considered trimming them down.
My first suspicion was that I might be hitting the bump stops frequently, as that's exactly how it sounds. I tested by putting some butyl rubber (like putty) on the bump stops to see if it got squished. After normal driving around (with the noise present) the putty didn't get squished, so I don't think I'm hitting the bump stops.
#22
Member
Thread Starter
I've finally made a discovery with this that I think might well be the problem. I've jacked the rear end up, and noticed that both rear wheels feel like they have an excessive amount of end play. It also makes a noise very similar to the one I hear over bumps when I wiggle the wheels.
Being a C-clip Dana 35, is this related to the wheel bearings or is there something else I should look at?
Here's a quick video I took:
Being a C-clip Dana 35, is this related to the wheel bearings or is there something else I should look at?
Here's a quick video I took:
Last edited by Brynjaminjones; 11-01-2021 at 02:21 PM.
#24
Member
Thread Starter
Thanks Dave, is that the only thing it could be?
If so, is it simply a case of replacing the spider gears, or would there be more involved?
I'd also appreciate your opinion on whether you think this would cause the clunk over bumps I'm hearing?
Sorry for the multiple questions - I'm a little out of my depth when it comes to differential work!
If so, is it simply a case of replacing the spider gears, or would there be more involved?
I'd also appreciate your opinion on whether you think this would cause the clunk over bumps I'm hearing?
Sorry for the multiple questions - I'm a little out of my depth when it comes to differential work!
#25
CF Veteran
I did my 8.25, which side gear clearance is adjustable with shims. I cannot find any reference that you can do that with a D35 so I guess replacing them is the only option. I believe your Differential Side Gear Clearance is .0.12–0.20 mm (0.005–0.008 in.), and your play looks to be WAY more than that. I still had my clunk (or another clunk) after changing the spiders and adjusting the shims. Turned out it was a bad shock.
https://www.cherokeeforum.com/f2/spi...-axles-258837/
https://www.cherokeeforum.com/f2/spi...-axles-258837/
#26
Member
Thread Starter
Thanks, I can't seem to find any info on shims either. I've browsed through the FSM but didn't really find anything.
I guess the plan will be to get the shafts out this weekend and see how the spiders look. Should I be able to spot play in the gears with the cover off?
I've managed to replicate the noise even with the wheels on the ground, here's a video:
I guess the plan will be to get the shafts out this weekend and see how the spiders look. Should I be able to spot play in the gears with the cover off?
I've managed to replicate the noise even with the wheels on the ground, here's a video:
#27
CF Veteran
Yes you'll see the axles banging into the diff shaft.
I wonder if 8.25 side gear shims would work. I mean, all we're trying to do is stop the noise. It's not like the axle is gonna fall out.
I wonder if 8.25 side gear shims would work. I mean, all we're trying to do is stop the noise. It's not like the axle is gonna fall out.
#28
CF Veteran
#29
Member
Thread Starter
This has been really helpful, thank you!
Just to get your opinion, do you think it's likely that this is the noise I'm hearing when driving over bumps? I have noticed that it's worse when everything is cold - after a few miles it's still there, but less obvious.
I want to make sure it seems likely before going tearing into stuff that I've no experience with!
Just to get your opinion, do you think it's likely that this is the noise I'm hearing when driving over bumps? I have noticed that it's worse when everything is cold - after a few miles it's still there, but less obvious.
I want to make sure it seems likely before going tearing into stuff that I've no experience with!