Drivetrain Whine

[treue]

Guys:

9129 is running well and has about 700 miles on the restoration. The only problem is a gear whine which I think is coming from the differential. It starts about 30 mph and goes away about 60 and in that speed range is the loudest noise in the car. It is directly related to vehicle speed. It goes away or becomes quieter when the clutch is disengaged.

Is the differential supposed to be noisy or is it not adjusted properly? My shop had the whole rear axle apart, so everything should be OK.


Tom

[Timo]

Has this been discussed with the person/shop who performed running gear restoration ? IMO, as proprietor of restoration shop, I'd always recommend requesting (or allowing ?) the people who were in charge to begin with to look into it first since they should have most intimate knowledge what was done (or not?). If nothing else, they should made aware of this a.s.a.p. and perhaps consulted for advise or opinion.
Then, has the noise been there all of 700 miles or did it developed later ? Was it present before the restoration ? Is it noticeable in any gears or...? Etc......

[treue]

Timo.

Thanks for the reply.

The noise has been there since the beginning and at the same level. I don't know about the whine's earlier presence since I have only driven it post-restoration. My shop (Vintage Connection) will get their opportunity to examine the situation. I wanted a second opinion to decide if it was even a problem. I recall a video with Francois driving a 330 2+2 that had a whine in the background of the soundtrack.

Tom

[Zanny1]

When the gearbox on my C/4 was rebuilt to correct the slow 2nd gear syncho problem, it came back with a whine very similar to what you describe. The shop replaced some, but not all, of the bearings. While the 2nd gear syncho issue went away, the box was never the same in terms of noise. In neutral, the main shaft had a rumble (unless the clutch was disengaged) and there were all kinds of whines apparent while driving the car.
I believe that it takes a good shop to work on these gearboxes, particularly in terms of knowing what to replace and how to set up the tolerances properly.
You might try changing the oil to Royal Purple or Swepco, and see if there is a difference. I found the Swepco product reduce the noise a little.
BTW, the shop that did my C/4 box screwed up so many things on the car that I reluctantly sold it. This was a well known shop in southern California.

[treue]

Mike,

Thanks for the comments.

The transmission was also restored, with new sliders, synchros and bearings. It wouldn’t shift into 3rd and 4th because the 3-4 slider had some interference with its mating part. This issue has since been corrected. It’s still a bit notchy but is wearing-in well and seems to operate fine otherwise.

The whine is related to vehicle speed and does not change with the particular gear selected. It only goes away while the next gear is changed and returns when the clutch is released in the next gear and does not change in volume or tone except as the vehicle speed changes. It seems to be located in the rear seat area which is why I think it is the differential.


Tom

[DWR46]

You have described a classic rear axle noise. However, Chris Campbell is a great guy. Give him a chance and he will get it figured out for you. The problem with your synchros was related to a reproduction part not being the correct size as the old parts. This is becoming increasingly common in what we have to deal with today. So many repro parts are now being sourced from eastern Europe, and the quality is not always there.

[treue]

Dyke,

Thanks.

Chris had to take the tranny apart again to file some relief in the teeth on the O.D. of the sliders to get it to shift into 3rd and 4th. After that no problem.

Also, Chris will get his chance on the differential, probably sooner rather than later. I just hope I'm not doing any damage by continuing to drive the car. We drove Federico 100 miles today to the upholsterers (Dan Kirkpatrick Interiors, qv) for a few minor tweeks. I confirmed the symptoms mentioned above. It didn't get any quieter.

Tom

[DWR46]

Tom: I would not use the car until Chris has a look at it. You do not want to start a "bad' wear pattern on the ring & pinion.

[treue]

Thanks, Dyke. Understood.

[airsanford]

I was looking for parts a few weeks ago and ran across this site. Presented FYI.

http://www.ferraricraft.com/2010/05/one ... solutions/

[treue]

Tifosi,

After the discussion above, I parked the car and had Vintage Connection collect it and take it back to their shop.

They took the rear axle out and the differential apart. Not only was the ring and pinion (especially the pinion) damaged, some of the clutch disks were also damaged (see below). Chris at VC says the old gears were significantly out of adjustment. Multiple noisemakers, apparently.

They have the replacement parts on hand or on the way. Film at 11.

9129 Bad Ring and Pinion, 12-4-14.jpg (187.65 KiB) Viewed 12367 times

9129 Bad Differential Clutch Plate, 12-4-14.jpg (222.46 KiB) Viewed 12367 times

Tom

[John Vardanian]

Hi Tom, congrats! So, will they replace both ring and pinion, or just the pinion?

john

[250GT]

Hi Tom, congrats! So, will they replace both ring and pinion, or just the pinion?

john

People who try to save money will be punished .
and can do the job twice.
Ring and pinion are produced as a SET.

C.

[treue]

John and Cornelis,

As a set. Sitting next to the damaged old set is the smooth and proper new set (cropped out of the picture, above).

If one of the old parts were re-used, the damage dynamic would continue, transferring to (literally "infecting") the new part with things no better than before. Of course, correct adjustment and proper lubrication really helps in these situations. Adjustment of the differential hypoid gear set (qv) is quite involved and requires performance by those with experience and proper equipment. In my case the old pinion may have been a bit soft. Chris feels the gear set had not been properly adjusted. When the adjustment of these gear sets is not properly done, it will only end in tears.


Tom

[treue]

Guys,

The repaired differential should be back in 9129 soon. Vintage Connection put a used but serviceable ring-gear-and-pinion set in. Chris talked with some peers and the consensus was that used OEM was better than new reproductions.

Some pictures of the adjusting process (the nose of 9129 is in the first picture):

Measuring Play

330 Differential Play Measurement, 12-17-14.jpg (209.74 KiB) Viewed 12235 times

Ring Gear Concave Side Contact Pattern

330 Ring Gear Concave Contact Pattern, 12-17-14.jpg (218.65 KiB) Viewed 12235 times

Ring Gear Convex Side Contact Pattern

330 Ring Gear Convex Contact Pattern, 12-17-14.jpg (233.18 KiB) Viewed 12235 times

Tom