gear whine

[EMCD]

i just dropped a 3.23 sure grip rear end into my 72 cuda. the unit and gears looked almost new. i get a whine in 2 and 3rd gear when i let off the throttle. Do you think it might need to be shimmed? what could cause this?
Thanks

[Chryco Psycho]

The pattern is not set correctly on the gears . Are the gears new , if not you may never get rid of the whine

[EMCD]

so, what do i need to do to get them there?

[Chryco Psycho]

pull the gear set & change the adjustment , the power side of the gear is obviously close because it doesn't whine the coast side is the problem , you need to use a marking method to see how the gear mesh & determine from that which to adjust to make the pattern right

[EMCD]

Awesome! Thanks for the help

[EMCD]

ok, the tranny guy is saying $500 to fix the whine... I call BS. Could this really cost that much? Also, how many miles are too may to drive when i have this deceleration whine?

[72cudamaan]

Probably quoting 500 including a new gear set. All too often when a
gear set has a whine, it wasn't set correctly and the noise may never
disappear. The whine is caused by a micro layer of chatter that you
can't see or get rid of.  He may be doing this so that the job doesn't come
back looking like a failure on his part.

[EMCD]

ok, could i use the 3.23 gears that came out of my open diff? they never made any noise.

[Chryco Psycho]

ok, could i use the 3.23 gears that came out of my open diff? they never made any noise.

If the 323 gear set is in the same carrier , 742 for example , a gear set from a 489 will not fit a 742 carrier

[EMCD]

Cool. Are they stamped for easy identification? If I left the whiny gears in for a stretch, could it damage the possi unit?
 

[Chryco Psycho]

the carrier has a # cast on it  along the side of the pinion , as long as the carriers have the same # the gear set can be swapped , the other option is the swap the sure grip into the carrier with the 323 gearset . The whine will not hurt the suregrip .

[shadango]

Cool. Are they stamped for easy identification? If I left the whiny gears in for a stretch, could it damage the possi unit?

I dont know about whether it can damage anything....seems to me, unless the gear itself blows up, no.

But from a more objective standpoint --   A new gearset is probably costing the show $200 or so...so $300 labor.  Setting up a gear set is definitely (IMHO) an art.  Thats why I bought a prebuilt chunk from Dr Diff when it was time to change mine out.

Do you really want to take the chance on paying a shop to swap in a used gear set?  The shop cant guarantee THEY wont whine, since it is a used part.

Sometimes it is better to start fresh and pay the extra.

[Skeleton73]

Second that. Go new, Mancini has decent prices on gears.

I bought a 742 posi w/ 3.55s for $400 that was supposed to be perfect, and it's whined since the day I installed it...

[oldkimmer]

ok, could i use the 3.23 gears that came out of my open diff? they never made any noise.

..............................Put the suregrip unit into ur open diff.........kim.........

[EMCD]

cool. i'll try that. as alwats, thanks for the sage advice.