true trac

[GasGuzzler]

That's on the loose side for sure. It all depends on if they're GM gears (5 or 2 cut) or aftermarket. The newer style GM gears like to run tighter. I would use the manufacturer's specs on aftermarket gears.

The reason I said 0.009" was loose for new gears is because of the wear in you experienced....so they'd end up in spec. I doubt you'll gain any more backlash after 500 miles. I like to keep them under 0.008" but others might have a different idea.

[banker099]

well...they are aftermarket and they cam with no specs, i think they need tightened up cuz now i can hear a slight "whistle" about 55 mph

[GasGuzzler]

The way to do that now is re-shim and use a new sleeve (unless you have a solid spacer). You might get awat with adding 0.001-0.002" to the pinion shim but check the pattern because changing the pinion shim to tighten the backlash will also slightly change the gear mesh by moving the pinion into the ring.

Let us know how it goes.

[jetmech]

it measures 0.009" of backlash as of right now but all I did was replace the open diff with the true trac, I did not change the ring gear or pinion.

[GasGuzzler]

There's still a slight amount of maching difference in the carrier. Did you use new bearings? I hope so and if you did, it's on the loose side because they will wear in a little.

[banker099]

well...after talking to some guys last night they said feel of the diff cover after you drive like 5 min around the neighborhood and if it is pretty hot your back lash is set wrong,

and mine was pretty hot, along with them making a slight noise, so mine are coming back apart this weekend!

[jetmech]

I did use new bearings and it turned out the factory shims got it where it is now. I used the thicker shim on the side with the ring, so the ring and pinion are as tight as they can be with the factory shims. A friend of mine said that as long as the backlash is between 0.008" and 0.012" it is good and I'm at 0.009" now. I took his work for it cuz he has done countless rear ends and his Nova is EXTREMELY fast!! After we did the pattern check, the clean spots on the ring were dead center. As for the pinion, we didn't touch it aside from rotating the yoke to do the pattern check.