What symptoms does a bad differential exhibit ?

 

Clunk , grind
, whine ....geez this sounds a lot like a rice bubble ad !

 

Mine's got slight whining when off throttle. Mainly wehen coasting around 60-80 km/h. I ordered the bearings already, still the seals to go. I'll head to Al Tayer (local dealer) tomorrow to buy/order as many companies abroad don't send to P.O. Box.

QUOTE=myexcursion;1703021]What symptoms does a bad differential exhibit?

 

Btw can someone contact PiersXK as I quess I can't send private messages yet. I just want to know the garage he used building his diff in Dubai! 👍🏾

 

Hi acs370 ,

Did you manage to get in touch with PiersXK ?
I live in Dubai too and I'm having the exact same problem with my diff. Al Tayer motors is asking for more than 27k dhs...

Cheers.

 

 

Hi, thanks for your speedy reply !
Do you know what's the harm of driving with a noisy diff ? Can it damage the rest of the engine ?

 

 

It's almost always a gear mesh problem. As they wear they'll make noise. If the bearings go or the lash changes from gear face wear they'll make noise. Not much you can do about it except replace the gearset and hope your shop does a decent job with setting them up. Not difficult to mess up.

 

I can hear a whirring sound, sort of like an old aeroplane propellor, most noticeable around 60-70mph. Seems to be coming from the rear end. Had the car in for service yesterday, they didn't have time to properly diagnose it but said they checked the wheel bearings and they seem to be fine. They didn't do a road test, however so not sure how certain they can be. They want the car back to do proper diagnosis.

So could the sound I describe be a symptom of a failing diff? Anythig I can do to rule that or anything else out (the "freewheel test" maybe - I guess pop the car in N while it's exhibiting the noise)?

 

Put it up on a 2 post hoist so the wheels are off the ground, have someone in the driver's seat run the car in gear to the speed you normally hear the noise (DSC turned off of course).

Get underneath and listen for where the noise is coming from. Not exactly A+ health and safety practise but that's how the bad diff in my XJR was confirmed...

 

Thanks Cambo. No access to a 2-post lift so back to the dealer it goes.

 

I've bought a couple of litres of diff oil so going to change that out and see if that helps at all.

 

Look for metal filings , also any play in the diff pinion when rotating the drive shaft

Off the top of my head I don't recall seeing a drain plug, if there is a plug obviously remove and drain otherwise you'll need to suck it out the filler plug which you'll need a 3/8 ratchet to remove .

 

Unless your new oil is full of banana skins, it's not going to shut up a noisy diff.

If it's making noise, it's stuffed...

 

You know what, that's exactly what it's made of

Fair enough, I'm not the most mechanically minded but it's not going to hurt to change the fluid, as far as I know it's not been done and the car is showing almost 93k miles. I'll have a good look first, see if there's any signs of issue with the diff or the CV joints etc.

 

Maybe a 1/4 cup of saw dust .

 

The key with a diff is the setup. Installing new bearings alone won't do. The pinion depth, bearing preloads and backlash all must be re-measured and adjusted as necessary afterwards. Get it wrong and it will make noise. I found my diff to be on the very outer edge of spec when I did my Quaife. Installing the new bearings/races helped tighten the specs but we still changed the shims a few thousandths. This improved the backlash and the on/off slop was all but gone.

Here's the thread:

https://www.jaguarforums.com/forum/x...lation-155867/

 

Hi! I had this same problem with my 2007 XK coupe. Yes the noise is from the diff. Jaguar offered to replace it with a new and it would have cost 11 000 euros to me! So I found a repair shop here in Helsinki, Finland where they repare english cars. They opened the diff and told me that I had the same problem as many have had. Jaguar did the xk differentials negligently, they tightened the laurels too hardly, leading to premature wearing out. The repare shop offered to put new laurels to the diff for 1500 euros. Some had to be brought from USA. But the noise went away with this operation and it was much much cheaper than what jaguar offered. Hope that you can sort ti out!

 

Just a thought. Sometimes we forget the basics... Not sure on the 2007, however, early x100's have zerk ( grease) fittings on the rear axle universal joints. Rare is it people, service stations grease anything these days. Helped my 99 XK8. I also removed the rear behind axle mufflers for a wee bit of extra muscle sounding. I installed dynamat insulation in trunk area to remove the inherit drone from the exhaust. All well. Rich