[1970_Cloned]

1970 Cloned SS
400 small block
Turbo 350, w/ shift improver kit
10 bolt 2.73 open to a 12 Bolt 4.10 posi

I bought a 12 bolt rearend for my 1970 chevelle in January and it had 2.56 open. Anyway I was going to put in a new auburn posi and 3.73 gears. It ends up a guy of a guy had a 12 bolt posi with 4.10 gears I got them for 150 bucks. I bought it and had a guy that I was told he was good at setting up rearends put them in. Any way I put the rearend in the car. It makes a whine when I let off the gas and at constant speeds (more or less all the time it makes this whine). I had him listen to it and he said he would look at it next week. So who has been in my situation before? Are the gears screwed up or is the posi unit bad or is it installer?

*The posi works great two solid black marks!
*Boy does it haul *ss, what a change from 2.73 gears
*All the bearings have been replaced
*I get 2nd and 3rd gear scatches every time with the 400 stock motor that is out of a mid 70s impala
*The installer has a pulling truck that he built himself gear change, motor etc, he wins almost all the pulls around here.

I am all ears so any input is appreciate any input
Thanks

Ben Matheny
Team Chevelle Gold Member #214
Kearney Ne

 

[260]

I bought Aurburn gears and they were noisey.The set up was fine.I heard richmond are noisey as well.Precision gears are cut as close to factory specs as possible,same with Motive.These gears run hotter though.Could just be the gears.You will be able to tell if the rear was set up right once you inspect the wear on the gears.

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Dean Ciampi
Autumn Gold 1970 LS6 Chevelle
Team Chevelle Gold #52 Aces #3094

 

[Wally]

Gears make noise for several reasons, most are not good reasons.

1. The gears were worn or not installed in the original housing correctly and caused excessive wear. You can feel this, very sharp edges on the ring gear and pinion.

2. Pinion depth not correct. This will cause a whine in the gear.

3. Ring gear shimmed incorrectly. This will cause excessive backlash or if it is set in to deep to little backlash. To little is way better than to much.

As for the posi unit, GM type four carriers do not make noise, I have never used after market posi units.

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Wally
Gold #67
67 malibu

[This message has been edited by Wally (edited 07-15-99).]

 

[Jason Shulenberger]

I don't have the answer, but...

I had a 72 chevy 4x4 that would make a noise in the rear end when I let off the gas. If in 4wd, It would never make this noise. (the rear end never had slack on it in 4wd) I believe the pinion gear may be the problem. Did your rear end man give a good look before installing the gears? Sold the truck so I don't know the fix for mine.

 

[L6571SS]

I wouldn't use the Auburn posi. Mine started poping before compleatly letting go after only about 4000 miles. The driveline shop says they have had numerous people with the same problems over the last year or so.

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JT
71 SS 350 soon to be Vortec 355 then a 454
www.angelfire.com/co/KellyMotorsports

 

[1970_Cloned]

Thanks for your input, it gives me an idea what is wrong with my rearend.

Ben Matheny
Team Chevelle Gold Member #214

 

[Dave Birdwell]

Were the gears new or used? If they were used any at all, they will have a pattern worn into the gearset, and it would be very hard to put them into a different housing and achieve the same pattern. If it's making noise, you really shouldn't be getting on it until he can listen to it. More than likely you'll just have to live with it.

 

[Clint44]

L6571SS, just because you had a problem with Auburn posi units,doesn't mean they are all bad or junk. My 68 Elky with 468",700R4,and Richmond 4.10 gears is still totally quiet after 4 years & 30K miles. When someone doesn't install something correctly and it fails, the installer will never take the blame,,it's always the part was junk. Wish I had a dollar for every time I've heard that.