Rear fixed, noise is gone
Thread Starter
Le Mans Master
Joined: May 2002
Posts: 5,086
Likes: 786
From: Lebanon Township New Jersey
Rear fixed, noise is gone
In case anybody was wondering if this was ever resolved: After removing the diff the second time to look for the source of a noise after a pinion thrust washer had gotten chewed up in there, we noticed a slight nick on a ring gear tooth - on the coast side. We had spun the gears with a drill on the bench. Drive direction was quiet, coast side yielded a pulsing noise. This matched what I heard in the car - no noise on acceleration or steady speed but a slight grinding sound decelerating in gear.
So I got one of the last US Gear sets, 3.73 ratio. Thanks to Gary R for the heads up.
Gears are in, rear is in and a 10 mile test drive showed no noises or other problems.
I will eventually test it out on the track, with the drag radials but I'm not expecting problems. (I got both thrust washers in properly this time.)
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Wooo Hooo! good to hear it's all fixed!
Thread Starter
Le Mans Master
Joined: May 2002
Posts: 5,086
Likes: 786
From: Lebanon Township New Jersey
Le Mans Master
Joined: Aug 2017
Posts: 8,336
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From: Cool Northern Michigan
Now, is that the Heavy Duty diff cover from Muskegon Brake on there? The "ears" look thicker than stock.
The gear set box says: For Street Use. Likely a limited warranty issue incase you break something at the strip. It doesn't say Street Use ONLY.
Looks like one ring gear bolt was not torqued yet. But you took care of that, right?
Nice set-up.
The gear set box says: For Street Use. Likely a limited warranty issue incase you break something at the strip. It doesn't say Street Use ONLY.
Looks like one ring gear bolt was not torqued yet. But you took care of that, right?
Nice set-up.
Last edited by HeadsU.P.; Mar 16, 2021 at 09:23 AM.
Thread Starter
Le Mans Master
Joined: May 2002
Posts: 5,086
Likes: 786
From: Lebanon Township New Jersey
Now, is that the Heavy Duty diff cover from Muskegon Brake on there? The "ears" look thicker than stock.
The gear set box says: For Street Use. Likely a limited warranty issue incase you break something at the strip. It doesn't say Street Use ONLY.
Looks like one ring gear bolt was not torqued yet. But you took care of that, right?
Nice set-up.
The gear set box says: For Street Use. Likely a limited warranty issue incase you break something at the strip. It doesn't say Street Use ONLY.
Looks like one ring gear bolt was not torqued yet. But you took care of that, right?
Nice set-up.
The ring and pinion are replacing the same brand gears that I had in there since the rear was rebuilt about 7 years ago. I had no problem with them over a couple hundred runs on drag radials. What started this round of rear end work was worn clutches in the posi unit. The ring gear got damaged by a spider gear shim (thrust washer) that I didn't reinstall correctly. Regarding warranty for R&P failure with this new set - I wouldn't even try to pursue that and hopefully I won't have to.
Ring gear bolts are Lock Tited and torqued, believe me. But thanks anyway.
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Tech Contributor
Joined: Aug 1999
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From: Connecticut, USA
Looks good but you still didn't want to tune the posi? Either way good luck with it. Street gears are harder then drag gears and those are meant just for drag racing, they won't last long in a street car due to be soft for the impact of hard launches.
Forget about any warranty, hard to do when the company is pretty much absorbed and stopped making gears.
Not a bad idea to replace the gears after years of hard service. I just had to replace a set of 12 bolt that sheared some teeth after 9 years of hard use. Nothing is bulletproof regardless of what some builders promote, everything has their limit.
Forget about any warranty, hard to do when the company is pretty much absorbed and stopped making gears.
Not a bad idea to replace the gears after years of hard service. I just had to replace a set of 12 bolt that sheared some teeth after 9 years of hard use. Nothing is bulletproof regardless of what some builders promote, everything has their limit.
Thread Starter
Le Mans Master
Joined: May 2002
Posts: 5,086
Likes: 786
From: Lebanon Township New Jersey
Looks good but you still didn't want to tune the posi? Either way good luck with it. Street gears are harder then drag gears and those are meant just for drag racing, they won't last long in a street car due to be soft for the impact of hard launches.
Forget about any warranty, hard to do when the company is pretty much absorbed and stopped making gears.
Not a bad idea to replace the gears after years of hard service. I just had to replace a set of 12 bolt that sheared some teeth after 9 years of hard use. Nothing is bulletproof regardless of what some builders promote, everything has their limit.
Forget about any warranty, hard to do when the company is pretty much absorbed and stopped making gears.
Not a bad idea to replace the gears after years of hard service. I just had to replace a set of 12 bolt that sheared some teeth after 9 years of hard use. Nothing is bulletproof regardless of what some builders promote, everything has their limit.
Thread Starter
Le Mans Master
Joined: May 2002
Posts: 5,086
Likes: 786
From: Lebanon Township New Jersey
Tech Contributor
Joined: Aug 1999
Posts: 15,175
Likes: 3,989
From: Connecticut, USA
I found that as well with a new US Gear set out of the box. A small burr, not a crack or anything that would be an issue using the gear set but enough that I heard if in my spin test. Once it was dressed it was perfect and has been in use for years. Probably happened going from final lapping to packaging at the factory. Then I had one of the last made in usa Richmond 355's dial in text book perfect. Literally the final pattern came out amazing if I say so myself. They howled terribly, a local guy had them and I couldn't believe what I heard, not a whine at 50mph as US Gears may have but a constant high pitch howl at all ranges. I replaced them with Tom's 355's and again got a perfect pattern that was dead quiet. Going forward with imported gears today- who knows. Glad you got those 373's when you did. I put some sets of 308 336 373 on my shelf as well.
Thread Starter
Le Mans Master
Joined: May 2002
Posts: 5,086
Likes: 786
From: Lebanon Township New Jersey
In my case the gears were quiet before the thrust washer got ground up in there. We finally found the damage on the ring gear while doing the spin test slowly in each direction. While going in reverse, the slight pulsing could be heard or felt, roughly every fourth time the pinion went around. Since the ratio is close to 4 to 1, (3.73), we knew the damage was on the ring gear, on the coast side. After scrutinizing the gear, tooth by tooth, we noticed a spot on the ring gear that was unusual (burr, nick?). When we rotated that spot, in reverse, by hand, while putting some resistance on the ring gear, it could be felt every time that tooth contacted the pinion. Those gears might have lasted indefinitely in there with no problem other than the slight noise I was hearing. But who knows?
I will try to get a pic, for conversation purposes.
I will try to get a pic, for conversation purposes.
Thread Starter
Le Mans Master
Joined: May 2002
Posts: 5,086
Likes: 786
From: Lebanon Township New Jersey
We put yellow marker on the ring gear before we spun it to possibly show the bad spot. It did help a little.
Can you see the light area within the black marker? That is the bad spot. It doesn't feel high or low there but it drags a little on the pinion on that tooth. It is amazing to me. Maybe that tooth is bent slightly. The pic shows the drive side. There is a similar mark on the coast side.
This shows the potential risk in installing used gears, in my mind. I don't think anybody would notice anything on a visual inspection.
Disregard the styrofoam pieces. They are from the shipping box for the new gears.
Last edited by BKbroiler; Mar 17, 2021 at 05:49 PM.
Old Pro Solo Guy
Joined: Dec 2017
Posts: 8,094
Likes: 4,449
From: Marlton NJ
Thanks for the detail. nice to know,
BTW" I really like the radiused edges on your posi unit window. With 7 years of hard launches on yours I feel more confident that my posi may last a while after all.
BTW" I really like the radiused edges on your posi unit window. With 7 years of hard launches on yours I feel more confident that my posi may last a while after all.
Thread Starter
Le Mans Master
Joined: May 2002
Posts: 5,086
Likes: 786
From: Lebanon Township New Jersey
The reason I did the radius grinding on the edges is that with all the talk here about cracks I looked and noticed the one in the pic. It was easy enough to grind that out and to continue around the 2 big openings. We also magnafluxed it at that point and didn't see any further problems.