Odd transmission noise

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MikeGreer
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Odd transmission noise

Post by MikeGreer » Mon Oct 29, 2018 10:44 pm

So it was a beautiful Fall day today and we took the spider out for a drive to see the turning leaves. We probably drove about 200 miles. Out of that, there were three instances where when I let off the gas, the car made a whirring sound until the accelerator was reapplied. This happened in multiple gears including 5th. And as quickly as it started it would stop and I could drive for miles without the whirring sound. I think it was the transmission, can't figure what else it could have been. Any ideas what this might be and what to do about it?
45 years with a spider, that's a long time
Restoring the '79 for the second time, you're never finished ;)
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ST3Racer
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Re: Odd transmission noise

Post by ST3Racer » Tue Oct 30, 2018 12:29 am

It sounds (lol) like a clutch release bearing, or pilot bearing. They don’t last forever.
Bill McMahan
Parker, Colorado
'69 124 Spider 2L ex EP racer, ex Volumex NASA ST3 Racecar - retired
'69 rebodied with '79 backdated chassis as '72 DP 1.8L Vintage Racer
'74 124 Abarth Stradale Replica
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sunracer
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Re: Odd transmission noise

Post by sunracer » Tue Oct 30, 2018 1:09 am

sounds to me like rear differential wear starting. Check/drain fluid examine for metal
Pierre
former owner of many spiders...notably the Sunracer, Sleeping Beauty and the Rat Rod : )



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MikeGreer
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Re: Odd transmission noise

Post by MikeGreer » Tue Oct 30, 2018 9:12 am

Thank you both, both of those crossed my mind, because I couldn't tell for sure where the noise was coming from. The rear end is at least easy to check, or at least check the oil for metal. I hope however, it's not, because this is maybe the 4th for this car, and this one went in just a couple of years ago. The release bearing, I'm not sure when it was last replaced.
45 years with a spider, that's a long time
Restoring the '79 for the second time, you're never finished ;)
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davedecker4
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Re: Odd transmission noise

Post by davedecker4 » Thu Nov 01, 2018 2:32 am

Also check carrier bearing on the driveshaft.
Dave Decker
a 'couple' Fiats and Lancia's
fp55scca
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Re: Odd transmission noise

Post by fp55scca » Thu Nov 01, 2018 10:38 am

MikeGreer wrote:
Mon Oct 29, 2018 10:44 pm
... drove about 200 miles....
...there were three instances where when I let off the gas, the car made a whirring sound until the accelerator was reapplied.
...This happened in multiple gears including 5th.
...as quickly as it started it would stop and I could drive for miles without the whirring sound. .
---------------------------------------------------
--Mike, from your description, the problem occurs when you unload the drivetrain. As others have suggested, this can be a bearing, or a gear. Good suggestions have been made here.

--One additional, and simple thing to check: be sure the lower front inspection panel on you bellhousing is tight. It is shaped like a trapezoid and attached with two 8mm and two 6mm bolts. If loose, vibration can cause it to make a whirring sound.
Jim Scurria
Norfolk, VA

1972 Fiat 124 Spider
1971 Spider - SCCA FP-24
1974 CSA Abarth Replica
1981 Fiat Spider Ratrod
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San Jose Steve
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Re: Odd transmission noise

Post by San Jose Steve » Thu Nov 01, 2018 11:10 am

I had a similar noise.....at 1st I thought it was the transmission, but it became louder over time to make it obvious it was coming from the back seat area. I got a new pumpkin from AutoRicambi and the noise disappeared. Had to be the best money I spent on the car all year as it was really making me crazy, especially while coasting downhill in gear. Super easy to swap out too once I purchased the right angle snap ring pliers on Amazon. That cheap little tool took all the frustration out of getting the axle shaft out. -Steve
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MikeGreer
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Re: Odd transmission noise

Post by MikeGreer » Thu Dec 27, 2018 12:30 pm

And the winner is . . . it's the rear end! I've driven it more, took some time to do this, and finally put it up on jackstands, put it in gear and had my son-in-law listen. No question at this point the noise is coming from the rear end. I slid under, after turning the car off, and grabbed the drive shaft close to the differential and shook it, it moved quite a bit more than I expected.

It's a '79 so it's not a pumpkin replacement solution. So question is can they be rebuilt and if so, who can do that type of work? I can remove the entire rear end, I've replaced it before. I'd rather have new parts and more life expectancy than to try to locate another used pig in a poke. What say the experts here? As usual your advice is greatly appreciated. Thanks,
45 years with a spider, that's a long time
Restoring the '79 for the second time, you're never finished ;)
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SimcaBertone66
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Re: Odd transmission noise

Post by SimcaBertone66 » Fri Dec 28, 2018 10:57 am

Commercial recommendation .. contact Jon Logan, Midwest 124 and ask him what to do.....
Joe DeGasperis
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MikeGreer
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Re: Odd transmission noise

Post by MikeGreer » Fri Dec 28, 2018 2:43 pm

Thanks Joe, I've known Jon for years and sent him a message yesterday. I have a couple of things to check, like how much metal is in the oil and if the pinion nut is tight or not, but after that it looks like an old style rear end with the 3.9:1 pumpkin installed with new axle bearings and oil seals and a rebuilt drive shaft that fits the new rear end is in my future.

I find it odd that new ring and pinion gears are available from the vendors for the new style rear end, but no one seems to rebuild them.

Also does anyone know if the panhard rod is unique to the rear end or the car? In other words if you have an old style rear end, do you use the old style panhard rod even if it's a spider 2000, which has the new style panhard rod? Which is it supposed to match?
45 years with a spider, that's a long time
Restoring the '79 for the second time, you're never finished ;)
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