Questions to ask your gear installer

[Joe M 2012 2SS]

I've read many good threads on C5 in regards to gear swaps, but none address one thing.

What questions should you ask the person installing your gears?

If your like me, you don't have the tools, or the complete understanding of how to DIY, so your getting someone else to do the work. What you need to know is what questions to ask the installer before you agree to let him do the job.

Don't just assume because someone has a nice looking shop that they know how to do it properly.

This is information I wish I would have known, as I had a bad install job done recently.

When installing aftermarket gears on a G5 Camaro, after the pumpkin is removed and the factory posi /ring gear, and the pinion are removed, this is what the installer should do.

I know this is fact because I spoke with a gentleman today who used to be a head mechanic at a GM dealership, who now has his own shop.

1) The first thing is to check the gear and count the teeth on it, also the teeth on the pinion. Gear ratio is derived by dividing the amount of gear teeth by the amount of pinion teeth.

2) Once it is inspected, cleaned and checked for defects, the pinion is installed.
Aftermarket pinions have a number written on them, this is the pinion depth, it has to be set +/- .002 inches.
Just putting the factory shims back in will not ensure that it is within this tolerance. A pinion depth gauge must be used to ensure proper depth.
If he tells you this procedure is not needed, find someone else. The pinion must also be preloaded properly after it is set with a gauge.

3) The backlash is checked next, and also requires a gauge. The factory gears are a 2 cut, while many aftermarket are 5 cut. The backlash for a 2 and 5 cut aren't the same.
Shims are also used to set proper backlash, again just putting factory shims back in and going with it isn't doing it right, it must be checked with a gauge.
If your installer cant tell you what the backlash will be set at, and what cut the gear is, find someone else.

4) The last thing to be checked is the pattern on the gears, a paint is used to mark both sides of the ring gear, one side is drive, the other coast.
These should be as close to exact center as possible. If your installer says its OK for them to be towards the heel or toe, find someone else.


So basically you need to ask these questions.

What is your process for inspecting a new ring/pinion?
How do you set the pinion depth? Which gauge do you use to set preload?
How do you set the backlash?
What pattern do you look for on the ring gear when checking it?

If your installer cannot answer these questions correctly, your very likely to have a gear set that is not installed properly.

Don't be surprised if you hear people say, I have X amount of years of experience, I don't need gauges, I can feel when its right.
Or I just put the factory shims back in and it comes out right.
Say.......OK thanks, have a nice day, goodbye.

I didn't know to ask all these questions when I had my install done, and I hope this thread will help someone seeking an installer for their gears to find someone who does them properly.