Front End Rumble?

[UKJeepThang]

OK, so my XJ has not moved for 6 months as I've been doing bits and pieces to it over the winter.

This weekend, I replaced all the fluids and greased everything, started her up (first time) and took her out for a run. It's developed a low sounding rumble from what sounds like the front end when she moves off. A bit like a low rumble /rat tat rat sound that increases with speed.

I've checked all the mountings etc. and everything looks fine.

Any thoughts as I can't find anything that is obvious.

[cantab27]

suspension, ya think ,or running gear

[Mudderoy]

OK, so my XJ has not moved for 6 months as I've been doing bits and pieces to it over the winter.

This weekend, I replaced all the fluids and greased everything, started her up (first time) and took her out for a run. It's developed a low sounding rumble from what sounds like the front end when she moves off. A bit like a low rumble /rat tat rat sound that increases with speed.

I've checked all the mountings etc. and everything looks fine.

Any thoughts as I can't find anything that is obvious.

I bet it is a bearing that didn't like sitting still for that long.

[4.3LXJ]

If it increases in frequency with speed then you have two options. Unit bearing or axle u joint. The rata tat tat makes me lean more toward the u joint.

[xj4life2]

Shocks after sitting can do that also I would look at tires, I know mine don't like to sit, after a couple days of driving it does go away though. Generally its just a flat spot in the tire.

[UKJeepThang]

Thanks for the comments, I'm pretty sure it's not the shocks and the tires have been off the XJ for the whole 6 months.

I can see where you are coming from re either the unit bearing or the axle UJ so is there a simple test to do on each one to find out which is worn?

[4.3LXJ]

Make a hard left or right and see if there is an increase in the sound. If there is, then it is the u joint. If not. probably the bearing. If you pull one you have the other out anyway. You can see if there is any rough operation in either then.

[UKJeepThang]

OK, so I jacked up the front end tonight, grabbed the tire at 12 o'clock and 6 o'clock and attempted to wiggle it to identify if there was any play. There wasn't anything, solid as a rock so I'm assuming the hub bearings (unit bearings) are fine and are not worn. Therefore I'm pretty sure it's the UJ's.

Whenever something wears out, I always try and upgrade.

Can I upgrade the UJ's to something stronger? If so, to what?

Will I have to replace the axle shafts in conjunction with stronger UJ's or can I upgrade the UJ's without upgrading the axle shafts?

All advise gratefully received! :thumbsup:

[UKJeepThang]

Any ideas on upgrade to the UJ's or is it just a case of replacing?:thumbsup:

[4.3LXJ]

No cheap upgrades for the 98, unless you go to chrome moly shafts with larger ujoints.

[UKJeepThang]

OK so I removed the axle shafts last weekend and there is absolutely no play in those UJ's at all.

So it's not the hub bearings and it doesn't seem to be the axle shaft UJ's.

Any more ideas out there??:confused:

[4.3LXJ]

You might try swapping tires front to back just for giggles, but probably the wheel bearing.

[UKJeepThang]

I think I've found it. There is a small amount of play in the front propshaft where it exits the transfer case so presume the joint is worn. Now is this an easy job or a PITA?

[4.3LXJ]

Better ale sure that is it. Yu will have to remove the case and disassemble it to tighten that up.