3.91 gear reliability question

[KerseySS]

I had my son take my car and gear to the mechanic to get a quote for the gear replacement. The mechanic that is going to install my gear saw my son leave his parking lot going fast. I talked to the mechanic today and the mechanic stated that since the car will be driven agressive that he would not provide a warranty and the gears will start to wine if driven hard. My question is, do the 1LE 3.91 gears wine after being driven aggressive? Are these gears reliable? The mechanic is some what being a prick, but I understand his point. It's actually hard to find someone to do it at a reasonable price.

[cc-rider]

He's just trying to cover his ass for a potentially bad gear job. No, gears don't whine after hard driving. Maybe after 50k miles of hard driving. But gears whine due to bad tolerances and installation.

[KerseySS]

Originally Posted by cc-rider

He's just trying to cover his ass for a potentially bad gear job. No, gears don't whine after hard driving. Maybe after 50k miles of hard driving. But gears whine due to bad tolerances and installation.

Thank you for the info. The mechanic is a reputable guy, but I am starting to worry a bit. If the gears are going to wine from bad installation, will it be right away or could it start over time.

[cc-rider]

Do some research on gear installs and the lash, offset, etc. It will make different noises depending on what’s off. Whining on acceleration means one thing...whining on deceleration means another thing. But it has to be done right. And if done right, it will not whine.

All that being said...sometimes a diff will whine a LITTLE bit. Pinning your ear to the floor of the trunk and hearing a faint whine is not what you should be looking to do. And even hearing a little bit of an audible whine on decel or something like that might not be a big deal.

It’s just kind of a BS thing for your shop to say just because he saw your boy leave a bit spirited. Yes, driving a car hard is harder on the differential for sure. But I find that a bit odd that he declares no warranty before even installing it.

[CamaroFred]

Why did you have to show him the car? Doesn't he know what a Camaro is?
Ask him, "WTF do you think I want 3.91 gears? Driving like grandma?"

[frankwjr]

you need a new mechanic...did mine myself, in the garage on jack stands, gears practically fall in fer cryin out loud and I also replaced all the bearings too...whisper quiet, 2 trips to the 1/4 and 1k plus miles goin up daily...good luck!

btw - used the OEM 1LE gears...

[JMI]

The GM gears are not as bad for break in period but I still suggest it to take it easy abit and do a few heat cycles. Aftermarket gears really need a break in period and heat cycles up to 500 miles.
Main reason is the OEM gear is a 2 cut and the aftermarket is a 5 cut gear.

[KerseySS]

Thank you all for the information. After sleeping on it overnight, I am going to find someone else to install the gears. What the mechanic told me makes no sense, if he was correct why doesn't my current gears whine? Thanks again everyone.