I got a 3.23 open rear out of an '84 camaro, put in a zexel-torsion posi, torqued the main caps to 50 and the ring-to-diff bolts to about 80. After 7 hours of hard work, the lil bastard is in, but there is an annoying gear whine. It is worse when I am giving it gas, but when I let off it becomes about 50% quieter. Anyone know what this is caused from?

Thanks,
Brandon

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White '92 Firebird w/ 305 TBI. Open element w/ non drop base, increased fuel pressure, TBI spacer, Hedman Hedders & y-pipe, no cat, cat-back exhaust

 

Its because you didnt get the preload, backlash, and gear spacing set up correctly when you installed the gears. Take it to a shop and have it done professionally by an expert with the correct tools, before you break a tooth and the gears are junk.


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1991 Camaro Z28
5.7L 5-Speed (originally 305)
13.23 @ 107.62 MPH
Southern California
Member: SoCal 3rd Gen F-Bodies
Webmaster: SoCal F-Bodies
-=ICON Motorsports=-

 

If you just removed the ring gear and swapped it onto the new posi, there's a good chance the torsen's mounting flange isn't the same thickness as your old one, changing your backlash considerably.

 

Backlash should be set between 7 & 9 thousand.

 

If you have driven it much with that gear whine, chances are that set of gears will always make some noise. You are changing the wear pattern of the gears.

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82 camaro--original steering wheel, brake/gas pedals, seats--everything else modified
82camaro

 

what about the gears themselves.....are they heat treated?....aren't heat treated gears supposed to make that noise?
Rick

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'88 GTA 350 (very rusty)
Check out my car:
www.fortunecity.com/silverstone/brabham/42/

 

I thought the ring gear bolts were about half that for torque, but that was a while ago so I could be wrong. OEM 3.23's shouldn't make any noise. If they were richmond 3.73's or something, I could live with a little noise.


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82 camaro--original steering wheel, brake/gas pedals, seats--everything else modified
82camaro

 

Actually performance gears are softer than stock gears.. Drag race gears are softer yet.


I noticed 'slight' whine from aftermarket gears, but if it's really noticable, either the pinion depth is off or the backlash isn't set right.

Usually .035" of shim under the head bearing works.... You didn't forget to put this on before pressing the bearing on did you?

 

Do you know if the gears whined before you got them? By the sound of it you didn't set the backlash or preload. Take the cover off and drain the fluid. Check the pattern of the gears if they are out of whack, take the rear out and do it properly or have it done. I have had GM 3:23 gears and they didn't make a sound. I have 3:73's now (GM used) and they whine a little bit but i have put 1K or so miles on them and the noise has stayed the same. I also did the zexel posi swap like you did, great unit. Don't drive the car if possible until you sort this out!

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• 89 Formula 305 WS6
  SFC's, LCA's,
  Spohn Panhard Bar
  Air Foil
  Flowmaster Cat Back
  Tranny Cooler
  A/F Ratio Meter (not a mod but it sure spurs interest)
  Trans Temp Gauge
  Most "Free" Mods
  3:73, Zexel Torsion Posi
• 90 Eagle Talon 2.0
  (Winter Beater)
  Mods? Um, no

 

I think it might just be the pinion bearings, which is what I want it to be . I refuse to take the rear out after all the work i put in to installing it, so I'd rather just drive it till it craps out.
I understand what preload is, but what is backlash, and how is it adjusted? Also, what is the usual labor charge to change out the pinion bearings, and/or adjust the preload?

Thanks,
Brandon

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White '92 Firebird w/ 305 TBI. Open element w/ non drop base, increased fuel pressure, TBI spacer, Hedman Hedders & y-pipe, no cat, cat-back exhaust

 

Properly installing a set of rear gears takes experience & the right equipment to get the gearset to perform as it was designed. This means everything from quiet operation to strength to long life.
The primary measurements used to properly set up a gearset are the pinion depth & backlash of the gears. Preloading of the pinion & carrier bearing is also critical.

Places like Summit Racing can help you get all the pieces (carrier, bearings, seals, shims, etc.) to do the job right. However, one piece of equipment that is often overlooked is a 'pinion depth gauge' to correctly set how deep the pinion sits into the ring gear. Shims are used under the inner pinion bearing cone to accomplish this. Using one is a little tricky, but isn't everything until you do it a couple of times? The job can be done w/o it, but that takes even more experience & ingenuity.

Unless you're willing to risk the cost of a gearset, additional parts and all your time & effort, look into having a reputable shop set your gears up. Also, be sure to get references before putting the gears & car or axle in their hands. A friend of a friend of mine learned the hard way, after his gearset self destructed w/ only a few hundred miles on it, that some shops know how to install gearsets, but don't know how to properly set them up.

I bought a pinion depth gauge along w/ a very good instructional video tape from the following company. They advertised the most reasonable price I've seen for one.

Precision Measurement Supply
PO Box 28097
San Antonio, TX 78228
210-681-2405

Sorry to be so long winded, but I hope this information helps you or anyone else considering changing their gearsets.

 

Tab, if that rear-end is the one you purchased from me at the ballpark swapmeet, it was absolutely quiet when I removed it from my Z28. So the whine has to be a change in the dimension of one of the replacement parts, or maybe the pinion bearing preload. Hope this helps.....

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'84Z28/'92 305TPI
'92 complete rear suspension/PBR disc/Posi/3:42
Light weight 34.5mm stabilizer bar in front ($10 from wrecking yard)/
"wonder Bar" ($5 from wrecking yard)
23mm sta. bar in rear
Rear RS Springs (slightly softer than my Z28)
comp cam, flowmaster
TB coolantbypass/shutoff valve to heater core
powersteering cooler lines (liberated from another wrecked car of course)
MAT relocated
Ram-Air(home-made) gutted air-box
IROC ground effects/wheels GY245/50's
700R4 superior shift kit/ corvette servo(excellent shift kit btw)
home-made strut tower brace (cost $6)

Rebuilt engine and transplanted it myself.

Love this engine!

freshly painted OCT. 2000 Teal with two white stripes on the hood and deck lid

LOW performance people should drive low performance vehicles!

[This message has been edited by 84IROC (edited May 18, 2001).]

 

Well, here's the latest. I picked up front and rear bearings and races, and brought 'em to a guy I found who said he'd put em in for $90 (which I noticed was very cheap). When I went to pick it up, I paid for it, then noticed that, gee, the bearings were still in the backseat. Ended up, the owner thought I just wanted the pinion seal replaced, which explained the $90 (instead of about $200-250). I argued with the rearend guy, who told me that I should jsut get a new one, then we took it for a test drive. Guess what: the noise was gone. The guy told me that the pinion bearing came off very easily, and that perhaps it was not preloaded.
That was a few days ago, and now there is a barely discernable whine with the windows up and a/c off, nonexistent with the windows down. Anyone have any ideas why it would seem to be getting worse?

 

if all he did was change carriers he shouldn't have messed with the pinion,so how could it be out of adjusment? unless he did change gears