328 noise from diff...

First of all just try draining the oil and refilling with fresh good quality 75w90 synthetic.

You'll need about 4.5 litres.

Check your new oil to see if you need to add any anti slip additive as this will increase your chances of fixing it, but it is not always necessary.

If the car has been standing for years, the diff can actually rust as it sits high out of the oil, so bear this in mind. And to reduce this problem for the future, fill the gerbox with the car jacked on a nose down angle...basically over fill it by about 5-10mm, than rip off (with big pliers) the little spring loaded cap and fit a gearbox breather hose to the outlet on the bell housing to steer any waste oil away.

 

My old 78 did this.

I went to the local GM dealer and bought a 7oz bottle of Limited Slip "stuff"

I took about 50 miles for the sound to go away.

 

After you've done what ferrarifixer has suggested, find a large open space(like an empty car park) and drive in circles on full lock anti-clockwise and then clockwise. This will make the differential work hard and will help in reducing the groaning.

 

........and sing some rodeo favourites while you do it. One hand out the window whipping that beauty also works well.........

 

I am reading this with interest as my 328 does exactly the same thing. My car is now parked for the winter so I will read with great interest if what they suggest works for you.

I took my car to two mechanics and they both couldn't find it. I think you're on the right track.

Best!
Wes

 

I hate to be the bearer of bad news but I had to replace my diff for the same noise. It was the only to to get rid of it. I replaced the diff bearings, twice. A quick check to do. Jack the rear of the car and support on jack stands. Grab the inner axle flange were the axel bolts to the diff flange. Now move it up and down. There is a bit of allowable play there..but you will feel if it is accessive. Also look a the diff flange itself. If it appears like it rubbing on somthing then you have found your problem.

I took my old diff apart to find out what happened. Inside you have 2 metal shafts. On these shafts ride the spider gears for the diff. What happened in mine was both shafts wore out causeing accessive play in the spider gear which allowed the axel flange to move to much, making it contact the left side of the trans case. It would only make noise on hard left or right turns(as if you were parking etc.)

 

Tom, I know it's not always an indicator, but could you tell me at what mileage your diff packed it in? Couldn't you just rebuild yours?

My mechanics both said they wiggled and checked everything back there and it was all tight. So I'm still hopeful.

Thanks!
Wes

 

No NO NO. The noise is nothing to do with bearings, it is from the anti slip plates, usually where they are a little rusted or dry.

The oil change and circle work will fix it, and even if it doesn't, to get the whole diff out is just an easy job with the exhaust manifold removed first.

Takes about 20 hours to remove the diff, rebuild it on the bench, put it back in and done. Minimal parts needed too. You'd put new bearings and seals in while you're there, but it's not the cause of the noise, and the crownwheel bolts should only be used once.

To test it easily, just jack up one rear wheel, leaving the other on the ground and turn the raised wheel by hand.

It should feel smooth but tightish, with a static slip torque of about 35-50 lb ft when running through the driveshaft and wheel bearing/hub etc.

 

You make some good points..But I think were talking about 2 different types of noises. I tried all kinds of different fluids in my car. I took the diff out of it twice and disassembled it twice and soaked all parts in a bath of gear oil. This did not help the problem at all. I thought the same also..chattering clutch discs. Besides I drive my car all the time. It never sits for anything more then half a week. So the rust was not an issue with my car. It was internal diff componets wearing out inside the carrier.

The Bearings for the carrier are not the problem like ferrarifixer has said. I tried them twice as well and it did not slove my problem. It (on my car) was an internal wear issue.

The noise is a groweling type noise. Almost like a wheel bearing gone dry. Not a chattering. Like I said in my previous posts the spidergear shaft wore out causing to much play in the diff flange..which under tight turning conditions would allow the flange to just barely contact the left side of the trans case. You sould see the marks on the diff flange itself and on the trans case. I did everything in my power to aviod having to buy a new unit..but everything I tried did nothing..so I had to bite the bulit.

 

My diff went at about 40,000km. I could not find any replacement parts for my diff at all. Ferrari sells it as one peice at a price of 4500 bucks. I got one a bunch cheaper though (thank the lord)

 

So what ever happened? Did you pull the diff? Any changes to report?

Wes