Hi All. Firstly, thank you all for providing such a source of information and experience. With your help and reading here I've managed to repair my new (to me) 2000 xj8 base, including new f/shocks and mounts, all new cooling system, aux heat pump and valve, octopus hose, replaced missing heat shields, O2 and knock sensors, pulled the heads for a head and valve job and new gaskets rear shocks, springs and mounts and more. It sits at the right ride height, stops,goes, rides and runs as smooth as it should.

Just finished a 3200 mile round trip without incedent. I now have a significant whine or hum noise from rear drive train. Sitting in the back seat with another driver I cannot tell if its noisier on side or the other. I figure it's got to be either diff input or output bearings, axle u joints or wheel bearings?. If a bushing in the rear subframe has gone would that cause the noise, or transmit noise of one bearing or u joint nvh throughout the back end?

I cannot seem to locate the cause. The noise occurs when accelerating getting louder the harder or faster you go. The noise reduces when off the throttle or coasting. Noise increases with speed but at 71mph or 84 mph it goes away almost entirely, Either side of these speeds noise increases.

Any suggestions on how to diagnose this without just trying to throw parts at it?

Many Thanks

Andrew

 

Wheel bearings & differential oil should be checked.

 

Thanks,

I did a diff oil and transmission fluid and filter change before I left on the road trip . I've checked the diff oil level and color today and it looks clean and dripped out once i got the bung out.

I've jacked the back end and put it in neutral and tried to check the rear wheel for play and how each wheel rotates. Inconclusive. Need to buy some new axle nuts and find a hub puller before I get into the wheel bearings.

As an aside Mr, Charles, what colour green did you paint your xj? , looks superb

 

Thanks, it's HGD/British Racing Green.

I recently went through the noisy rear end saga. Mine ended up being remedied w/ a heavier weight differential oil(noise presented itself within 500 miles of a fluid change). If the noise surfaced after you did the rear end fluid change, then it points to that.

Here's my saga

https://www.jaguarforums.com/forum/x...w-noise-196918

 

Thank you. Yes, I used redline 75w90... I'll swap in 75w140 this week end. Not too bad a job now I've the right length wobble extension.

 

That was exactly my scenario, good luck !

 

You can also try adding MolySlip for gearboxes/axles. I have used it in BMW, Triumph Stag and jaguar S-Type diffs with great results.

 

Would be interested to hear the results, I've had a nagging hum/howl at 30/57 mph that happens after a couple mins of driving to warm the car up. Replaced the diff oil with 75w90 last summer, don't think it started around then but I honestly can't remember. It sounds like it's coming from the front end but the chassis ears haven't picked it up anywhere up there, and it wouldn't be the first time that the cabin has tricked me with sources of sounds.

 

W/ hindsight being 20/20, it took about 500-700 miles after my fluid change for the hum to present itself. I was so confident in the fluid that I ruled it out completely in my troubleshooting, turned out to be the culprit.

 

Hi all,

Replaced the 75w90 with 75w140 (Mobil 1 synthetic) and premixed/added 4oz molyslip as suggested. Usual way, sucked out the old fluid and pumped in the new. The 'old' 75w90 ran for about 3500 miles came out pretty clean, darker the it went in but still clear and see through.

1200 miles after installing the 75w140 the whine and hum noise is pretty much the same. Rats.

I plan to jack it up,Hand brake off and transmission in neutral and try and rotate, tug or lever stuff until I can find something not right.

Anyone have a lead to rent or obtain a rear hub puller?

thanks all.

 

You don’t need a hub puller. You do need like a 27 or 29 mm socket though. Can’t remember but it’s a weird size. Most of the ones I did the hub carrier would tilt down after the nut was removed.

 

I'll need a puller to replace the wheel bearings and U joints?

 

27mm for the rear axle nuts, just measured an old one I had lying around. Keep in mind they are one time use only, the "helicoil" like insert in them deforms when they're brought up to torque, so it eats itself when you remove them. New ones should still be available. I think I was able to tap the rear carrier off the half-shaft with a hammer once the nut was off, or it just slid off easily.

Don't need a hub puller for the U-joints but they seemed like a massive pain when I did them, so if someone has an easier method that involved a puller I'd defer to them. The U-joints are a pretty common size, can't find it in my notes but it may be in one of my threads or another U-joint thread on this x308 forum.

 

Thanks for the insights.

Yup, 27mm socket and a long breaker bar.

I have a set of axle nuts, wheel bearings and u joints for both sides on the way.

I have got to the point of trying to pull the hub from the rear carrier off the half shafts on both sides and they will not budge. Need a puller.

I'm contemplating dropping the whole back end and replacing bushings and checking the diff bearings and drive shaft bearing while I'm under there.

 

If you have the know how,tools & time I surely would. Those rear components get noisy & bothersome over time & usually fail/fall like dominoes lol, one behind the other.

Edit :
In fact I wish I would've done all mine @ once as so far I've done wheel bearings,shocks/rubber,taper/roller bearing all in separate sessions to troubleshoot a noise. Now w/ that done I hear another faint warble developing lol. Should've done them all @ once. Mind you I'm on a shop's labor rate as well lol.

 

You can check diff output shaft bearing play with everything still assembled by putting a runout gauge on the stub/spacer somewhere fixed and push the wheels in-out at 12 oclock. Some play is normal, factory max spec is... 0.15mm max play. Think mine are on the edge there or slightly above, iirc motorcarman said that's expected. Finding new bearings is a black hole, think originals are NLA but maybe you can sweet talk SKF France into getting some for you. I had no luck finding them but didn't go too far with that, got some decent examples off a junkyard car. SNG has some standard-sized bearings with spacers made to work for a reasonable price, don't have any experience with those though.

 

But first (firstly?), there are zerk fittings on both sides of the dif; try greasing them and see if that quiets things.

 

Thanks all,

I have greased the two zerks on each half shaft, one per u joint and it's not helped the noise. The zerks still had the rubber boots on. I removed the zerks, run grease through them, reinstalled then pumped grease into the joints. Seemed to take a lot of grease so I'm betting they haven't seen lube for a while. Going to replace the u joints and wheel bearings..

I've put a dial gauge on each side at the diff flange and get ~6 thou passenger side and ~9 thou drivers side. That's below and above the 0.15mm spec ..

Researching new diff bearings and seals.

I've wasted two new axle nuts and put it all back together to use for now.

I'm also planning on pulling an entire diff/ hub and carrier assembly from an 72k miles '02 xjr in the local breakers. The price is reasonable and I can refurb it at my own pace. Also has a rear antiroll bar if i want to install it.

 

An Update.

Dropped the back end entirely this weekend. Problem is in three places, Center Drive Shaft bearing , Drivers side differential output shaft bearing and drivers side upper U Joint.

Drive shaft bearing mount is loose with the rubber case torn away.

Drivers side differential has end play and feels rough compared to the other side. Don't know which bearing as the output shaft is still in there but I assume it's the outer.

U Joints seem fine, apart from the drivers side upper which doesn't move as freely as the others, feels a little notchy. .

Which one causes the noise I can't tell but I guess it's all additive.

Plan to replace wheel bearings and U Joints and subframe bushings, all of which I have on hand, Need to get a center shaft bearing and what needs replacing in the diff. And more axle nuts.....

BTW, missed the XJR back end, was too slow to get there.