What is the cause of gear whine?

[me32]

from what i understand, once the gears are installed improperly and have the whine, there is no fixing it with out another set of new gears. its from the way they mesh together.
alsways try and find a great shop to do gears, you get what you pay for

thats pretty much true. if they have been driven 1k or more, theres no fixing it cause they have already meshed together. mine has started to get whine now that i had to put on my stock Drive shaft and UCA, only on the freeway thoe. i never heard any gear whine before the the UCA and stock drive shaft. i even had the gears installed when i only had 1k on the car, still had stock exhaust and CAI. now i got 6k an it just started to get whine, maybe its just road noise viberating from UCA. but when i had the power house A/D i didnt hear the gear whine. its hard to say and it was over 100F out side too.

 

[19COBRA93]

I haven't installed as many as the ^^ other guy, but I've done probably 40-50 sets.

Backlash is only a part of the equation. The gear pattern (printed in the gear marking compound) is what is most important. If it's off, it'll whine. Other things to really pay attention to is the side bearing preload. If it's not enough, gears will whine. A LOT of installers don't setup side bearing preload high enough because it makes it difficult and time comsuming to get the carrier/ring gear in and out of the diff housing everytime you make/check an adjustment.

More than 75% of the gears I install are used. I backup every gear set I install. I've had to re-do a couple of them, but if the installer really pays attention to all, backlash, side bearing preload, and gear pattern they will not make any noise. Period. The problem is, some gear sets are a serious pain to get exact and it's incredibly time consuming. I've had some rearends take me an hour and a half. Others have taken me over 8 hours. It's a combination of adjustments that all have to line up in the end.

Like mentioned, installing gears is an art. And even good installers have a hard time with them. Any gear whine is from a bad install, and any gear whine, IMO, can be corrected without replacing the gear set. I've fixed gear whine in cars that have been there for thousands of miles. In those cases the gear pattern is what you have to pay attention to. Not the backlash. Make that pattern look like an almond with NO flat sides and you're golden.

 

[manOwar]

Chuck... Ride with me and you'll be good to go!!!!