308 GTBQV Banging from the back...

try jacking the car up at the right rear with it in neutral and rotate the wheels. if you have an axle, diff or brake problem, this would be they way i would check. you dont need the car up very far, just enough to rotate the wheel in neutral. you may have bad or damaged wheel / axle bearings in the hub if you heard the noises in neutral whilst rolling. i hope its not in the diff, as that is big bucks to rebuild ( $7000?) . best luck to you.


edit, i cannot remember if you have to have both wheels off the ground on a 308 or not to spin them. i just slide my jack under the center rear frame and lift up the whole rear end of the car when i am working on it. be sure you chaulk your front wheels while doing this! if you do have both wheels safely off the ground, put the car in 5th gear and slowly turn them and if you were driving forward, this will help diagnose the diff and transaxle. Michael

 

To rotate the rear wheels:
The 308 has a limited slip differential.
You'll need both wheels off of the ground, the trans. in neutral, park brake off, & chocks on each side of the front wheels to keep it from rolling.

Other alternatives are:

one of the CV joints in the rear half-shafts (ie: axles). Altho they usually make more of a clicking sound.

Could be some of the bolts holding the half-shaft to the outer stub axle, or differential have come loose.

Pulsing motion sounds like something's dragging for part of a turn of a wheel.
A broken ball in a CV joint bearing might cause pulsing also.

 

Verell
Pretty rare (but not inconceivable) for a CV joint to go, isn't it, assuming that it has been sealed appropriately? Wheel bearing sounds more likely, no?
Philip

 

Did your car get a lift to the garage this morning as planned?

 

When you see the labour and parts involved in changing the wheel bearing you will pray that it is the CV joints. They are a song in comparision.

 

Stig,

check your wheel nuts are tight. I had a banging noise on my 355 and had it towed from les mans last year only to find out it was a loose wheel ! Sometimes simple things are the solution... fingers crossed.

Philip

 

I'm betting this is a CV joint problem.....

 

I had something like this happen to me, except much more violent. Turned out that a tire had ruptured a belt and was out of round. I also had a tire do this on another car once, and it gave just a slight vibration at speed. When you put the car on the lift and spun the wheel you could see the "wobble".

Birdman

 

Wasn't intermittent at all, very clear palm of your hand sized bump on the tread when we got the wheel off.

Have you jacked up the rear end to see what things feel like when you turn the wheels & rotate them back & fourth?

 

Sounds like a wheel bearing since slowing with your brakes does not affect the noise and you did not mention any vibration. Differential issues can sometimes be felt through the shifter. Wheel bearing replacement in my area is about $350, maybe a little more if they have a hard time pressing them off. Not too much to swallow. Good luck, let us know what you find!
Jim

 

My bet is something is wrong (fouling?) with the brakes (rotor, caliper, pads?).

A frequency of 6 cycles per sec equates to the wheel rotation speed at a little under 30 mph which seems to tally with your observations. Something "wrong" with the tyre/wheel/brake assembly would give a sound at this frequency, whereas the bearings would be different. As the bearing's rollers/balls don't stay in the same place but roll around at 1/2 axle speed I'd think you would get a different rate of vibration if a bearing had gone, unless the inner race had broken-up. Diff bearings ditto.

 

Uh oh. Sounds like the diff to me. Hope not.

 

I'd forgotten the initial 'swishing sound'. Given it started this way, I'm suspecting that you've got a warped brake rotor. Initially the warpage was small & the high spot just wiped a brake pad each time around, thus the swishing. Brake pads float slightly, so the high spot would eventually force the pad far enough back so it would quieten down.

Eventually the warpage got to the point that it's dragging pretty heavily on the pad each time around. This will give you the feel you're describing. Also It'll be yanking the pad against the caliper body which would give a tapping sound.

It's much less noticable/obvious when it's a rear rotar than a warped front rotor.

You can measure the warpage by mounting a dial indicator on the rotor & putting the probe on the rotor.

 

To me it sounds like a wheel bearing. If it was the diff you would have been hearing a lot of "gear whine" before you started hearing anything like this! Also by loading up the rear wheel with a heavy angle of attack (in reverse with wheel locked) and getting more symptoms out of it, I'd say... wheel bearing. I've gone through two on my car (non Ferrari but mid engine) and it was usually a grinding noise, not a lump noise. I had a lump noise once but that was a bad tire (same as posted above) that had broken a belt on the inside. That tire also would up loosing its tread in grand style on the freeway. As said before check out that tire as well.

I’m usually not one to throw parts at a car in order to fix things but you may want to change out the wheel bearing and see if that fixes it. Granted it may be the diff (though I doubt it) and if it is you’ll look at the wheel bearing as an unneeded expense. But, you’ll need to replace it sooner or later and so you’d be having to go through the expense at some time down the road. Might as well do it now, get it out of the way and see if it cures it. I hate giving that advice.

 

We shall be praying for you (and BB), in chapel, tomorrow.

 

How many miles are on the car? It would seem that for a differential to go it would have to be high mileage or not maintained.

George