360 - Driveshaft, Differential or Wheel Bearings?

Hi all,

My car has developed a problem and I'm hoping someone may by able to point me in the right direction.

I noticed new a droning noise had presented a few hundred miles ago. The noise is speed-of-car related, not engine speed related. I've had a good poke around, pushing, pulling, twisting, prying suspension bushes etc and couldn't find anything obvious. I decided to drive on and see what happens.

The drone hasn't become any more intrusive but I now have an intermittent clunk-clunk-clunk!

I'm hearing both the drone and the clunking noise. Not feeling it.

I think the noise is coming from the rear but I cannot be sure.

If I put the car into neutral and depress the clutch there's no change in the noise. If I change from one gear to another there's no change.

I've put the car up on stands and run it up to 170 kph and I can't recreate the problem.

All my pushing and prodding has revealed only a slight bit of movement in one of the upper ball-joints on a rear suspension arm. Everything else seems perfectly tight.

Front wheel bearings seem fine. Rear are hard to figure as it's difficult to get a feel for them given the resistance to turning by hand.

Gearbox oil is normal level and nice and clean.

Thoughts?

 

Thanks Tom,

Yes, track use, driving fast and turning mostly right, puts a fair bit of strain on the left hand side. Wheel (hub) bearings, while pretty resilient , have been known to require replacement all right.

I've been reading the WSM on removal of drive shafts and hub bearing. It seems to me the only way one is going to be able to diagnose the bearing is probably to get the drive shaft out so as to release the drag and get a decent feel of the bearing. Doing this also presents an opportunity to inspect the drive shaft too so I think I'll see if I can achieve this.

DIY capable I wonder? The 36mm (275 Nm) nut on the hub end of the driveshaft looks likely to be the most difficult part of the job. Additionally, the collar on the nut is caulked to the drive-shaft so that's not going to make it any easier to remove. I might need to see if I can borrow a heavy duty impact gun.

 

Yes, agreed with you here - but sure when you're up in the Northern Hebredies of Scotland and a slight drone settles in you've not a lot of choices!

Pic below ....

It's most obvious at a constant speed, not any particular speed, just when constant above say 45 mph at this stage. Cornering doesn't seem to have much effect as long as one maintains speed.

Actually, if I'd thought of that yesterday while I spent a good hour on that damn nut I'd have had the blessed thing off by now! Yes, that seems a pretty good way to proceed. It's easy enough to disconnect the drive shaft from the differential output and getting the nut removed thereafter would probably be a lot easier.

It's not possible to get the droning noise to present when the wheels are up. The stethoscope has revealed vague traces of the clunking noise but I can't localise it. It seems that it's as evident from one side to the other.

Think I'll whip off the hub-holder and shaft together as one piece and then take it to a workshop to have them separated.

Thanks for all the comments guys.

BTW - can anyone confirm whether or not this particular nut is regular thread or perhaps reverse?
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Update.

I spent last night with the google machine researching problems and gearbox / differential parts prices (gulp!) and got back to work this evening.

Ran the car on axle stands with wheels off. No change, vibration and clunk still there (but nowhere near as bad as when on the road).

Disconnected the left hand side drive shaft from the differential output (passenger side for me) and ran the car. No change.

Disconnected the right hand side drive shaft and immediately noticed play in the CV joint. Went back to the other side and compared and found that while there's a small amount of play it's very much less than on the right hand side. Ran the car and everything feels as smooth and quiet as can be.

Reconnected the left hand side and ran the car. Still perfectly smooth.

Next stage is to strip out the hub carrier and cart the lot off to a workshop to get the drive shaft removed from the hub bearing but at this stage I'm pretty confident I've found my culprit in terms of a worn-out drive shaft.
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Stripping down.....

Hey Curt, do you reckon I can release the hub bearing with drive shaft attached or do I likely need to release the entire hub carrier?
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Hi Bill, thanks for your input. Had you just a droning noise or had it progressed to intermittent clunk, clunk, clunk like mine? I can't help but feel mine is past re-packing with grease.

 

So, the hub, still attached to the carrier, with drive shaft still attached is out.

It's immediately evident that the hub bearing is toast. It's tight, dry and snags. Maybe the drive shaft is all right after all.

I'll need to bring it to a shop to have the nut on the end of the shaft taken off.

Hub bearing assembly is actually about half the price of a drive shaft so things might be looking up (or not).
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Yes, thanks for your suggestion, it led me down this road.

The parts are now with a local workshop and they're confident they can loosen the nut with their big vice and heavy-duty air hammer.

The hub assembly is sold as a complete unit with the ABS trickery attached. I think I'll just purchase a new one now and will then take the bad one to an engineering shop and check can they source a replacement bearing and if so whether or not they are confident they can change out the bearing without damage to the ABS section. Definitely worth the effort to make the enquiry.

 

Well, hopefully!

The helpful guys at a local tyre shop (they do a lot of heavy vehicle work) used their big air hammer to take off the hub nut from the end of the drive shaft for me.

The rest is told better by the photos than by me.......
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Further breakdown ......
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..... and the heart of the failure......
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Hub bearings are half the price of drive shafts so, for now, I'm just going to order up the replacement bearing and reassemble everything and see how I go. If other components require replacement I can build that into the winter schedule but I think this should be enough to get me back on the road and maybe even sneak in a last open-day at Mondello.

 

Ha! Wish I could help with any of those!

I imagine that multiple trips to the track (including serious heat) mixed with up to 60k miles of use basically just wore it out.

Not sure about the ABS sensor as I've not gone any deeper as I don't want to damage. I'll be bringing it to an engineering workshop at some stage to see do they think they can effect an economic rebuild.

 

Incidentally, for those that come behind me on this the curve of wearing-out items on a Ferrari 360 ...........

Initial noise was of a droning nature at speeds of 80 mph+

When the clunking first presented itself it was also at higher speed circa 70 mph + and at first I actually thought that part of my underfloor had come loose and was flapping about in the wind. (The car had bottomed out quite hard a couple of times over the Scotland jaunt so I thought maybe a fixing or two had given up).

The thread on the nut on the end of the drive shaft is indeed of regular thread. Anti-clockwise to loosen.