4.11 true-trac

[IWANTA(ss)]

So my GPI built diff was dropped off today. Would like to install it Monday anything special I need like new nuts bolts washers special break in fluid?
Any help would be greatly appreciated

[dino2012ls3]

My rear end shop supplied mineral base GL5 85W140 fluid to go back in rear end and told me do couple warm up and cool down trips. No hot rodding obviously. Like run get the groceries and back home type drive.

[IWANTA(ss)]

Originally Posted by dino2012ls3

My rear end shop supplied mineral base GL5 85W140 fluid to go back in rear end and told me do couple warm up and cool down trips. No hot rodding obviously. Like run get the groceries and back home type drive.

I got some advance auto brand fluid for the break in I’m gonna go with the Lucas in 500 miles when I change it. What gears do you have and how do you like the true trac?

[dino2012ls3]

Originally Posted by IWANTA(ss)

I got some advance auto brand fluid for the break in I’m gonna go with the Lucas in 500 miles when I change it. What gears do you have and how do you like the true trac?

I have Motive 410s with the Tru Trac. Haven't really been able to get on it since I did my clutch at the same time. But from what I've felt so far absolutely love them. It seems to really put me in my cam's power band fast.

[zlathim]

My advice is to stay away from prolonged highway speeds for the first 500 miles. It is also a good idea to invest in an infrared temp gun and make sure the diff doesn't get over 180* F during the break in period.

[IWANTA(ss)]

Originally Posted by dino2012ls3

I have Motive 410s with the Tru Trac. Haven't really been able to get on it since I did my clutch at the same time. But from what I've felt so far absolutely love them. It seems to really put me in my cam's power band fast.

I have the stock 3.91 I wonder is there going to be that noticeable of a jump for me. I just her to pick up about 500 rpm sooner

Originally Posted by zlathim

My advice is to stay away from prolonged highway speeds for the first 500 miles. It is also a good idea to invest in an infrared temp gun and make sure the diff doesn't get over 180* F during the break in period.

So no 60-70 mph for more than 20 miles and keep it under 180* for the break in.

[zlathim]

Originally Posted by IWANTA(ss)

So no 60-70 mph for more than 20 miles and keep it under 180* for the break in.

I was told to avoid highway speeds completely for the first 500 miles. That might be overly cautious, but mods like these are expensive and I tend to err on the side of caution. It sucked taking the back roads to work instead of the interstate, but that's what I did.

[IWANTA(ss)]

Ok yea I’m with better to play on the side of caution. She not DD anymore so I just take on a couple laps down the road and back when I get the diff in hopefully tomorrow

[IWANTA(ss)]

100 mile update.
A-So it’s loud I don’t know if it’s the gears or the poly bushings and the lpw cover but it whines something fierce.
Will that go away after break in?
B-With the slow 40-55 mph hits I’ve done in 4 th gear I feel like the power gets there a wee bit faster and the car feels like it’s digging into the rear lifting up the front more.
Is that the tru track working it’s magic?
Overall can not wait till the break in is over to go WOT and do some launch’s to really see the difference.

[alice]

If it whines as bad as you say it is, the whine is not going to get any better. The set up is probably the issue. I've set up rear gears all my life and gear noise is most always caused by improper pinion depth. The poly bushings amplify the noise for sure but is not the primary cause. I have 5:36 gears with 30.5" tall tires in my Camaro and though some gear noise is expected as you go up in numerical ratios, even with ratios as high as mine, I only have a small, acceptable amount. For sure, the poly bushings had to go because I hate noise.

The best lube for reduced noise levels is the Lucas brand. That is my experience. Your 3.91/4.10 gears should make little to no noise especially if you go back to stock bushings. Your noise will not wear in or go away until the gears are properly adjusted. Won't hurt anything but certainly is aggravating. As far as noticeable increase in acceleration, it will be a small amount. Usually, to notice a real seat of the pants improvement, you need to increase ratios in increments of .3-.4. But you should notice a difference. Have fun!

[IWANTA(ss)]

Originally Posted by alice

If it whines as bad as you say it is, the whine is not going to get any better. The set up is probably the issue. I've set up rear gears all my life and gear noise is most always caused by improper pinion depth. The poly bushings amplify the noise for sure but is not the primary cause. I have 5:36 gears with 30.5" tall tires in my Camaro and though some gear noise is expected as you go up in numerical ratios, even with ratios as high as mine, I only have a small, acceptable amount. For sure, the poly bushings had to go because I hate noise.

The best lube for reduced noise levels is the Lucas brand. That is my experience. Your 3.91/4.10 gears should make little to no noise especially if you go back to stock bushings. Your noise will not wear in or go away until the gears are properly adjusted. Won't hurt anything but certainly is aggravating. As far as noticeable increase in acceleration, it will be a small amount. Usually, to notice a real seat of the pants improvement, you need to increase ratios in increments of .3-.4. But you should notice a difference. Have fun!

I may be over exaggerating the noise I’m going to switch to the Lucas fluid whenever I make it a third of the way through the breaking so about 166 miles see if that helps.

[gunchamp]

Originally Posted by IWANTA(ss)

So my GPI built diff was dropped off today. Would like to install it Monday anything special I need like new nuts bolts washers special break in fluid?
Any help would be greatly appreciated

If you dont mind me asking, what was the price from gpi? Thanks

[bkevind]

Man I had Yukon 410 put in with my Truetrac of my 1LE. It was unbearably loud and never got any better.

I also had LPW cover, upgraded diff bushings, and the solid cradle bushings put in at the same time.

One issue is that whatever whine the diff is making will be greatly amplified by the solid bushings.

The noise wasn't so bad on the track, but driving to and from the track was unbearable.

Long story short I've got the GM 3.91 going back in with the Truetrac and hope it's a decent bit quieter.

The diff shop had a hell of a time taking the diff apart, they had to fab up a tool to get it open. So the original install was probably at fault, and maybe defective Yukon gear set.

[Pro-tuned]

I have full “polyurethane” BMR including cradle and diff bushings along with Tru-track and 3:45s no issue since installation 12,000 miles now. If I had to guess the issue I would say improper gear alignment...