True Trac or JRE mod?

[Cuda7050]

At the drag strip with drag radials I have noticed a moan sound coming from the rear end during burnouts. Someone said one tire is hooking up while the other spins while coming out of the box. So I am looking at an upgrade with gears in the near future.

I also run autocross and track days, so I don't want a posi that is going to shoot me sideways coming out of corners under hard acceleration. Can someone tell me the pros and cons of the JRE mod and True Trac set ups?

[blazzin1]

I have the True-Trac & 3.91's, I have not found any "cons" to it at all, it's great!!! Can't tell you much about the JRE Posi-Mod, never had it.

[IneedAZ]

also, call True Trac support, I spoke to the tech yesterday and he is very helpful. He did an article on the truetrac in a camaro for LSXtv
http://www.lsxtv.com/tech-stories/dr...ro-ss/?print=1

[Cuda7050]

That's good information, thank you. Do you think with gears you picked up .25 in the 1/4 mile as indicated in the LSXTV article?

[Synner]

JRE mod is way too tight for road course/autocross.

[Merc]

Originally Posted by Synner

JRE mod is way too tight for road course/autocross.

I agree been down that road and I'm just in the process of putting a 12 bolt Hammerhead in Pumpkin.

[Supercharged SS]

Originally Posted by Cuda7050

That's good information, thank you. Do you think with gears you picked up .25 in the 1/4 mile as indicated in the LSXTV article?

That's not gonna happen so don't get your hopes up.

[Supercharged SS]

Originally Posted by blazzin1

I have the True-Trac & 3.91's, I have not found any "cons" to it at all, it's great!!! Can't tell you much about the JRE Posi-Mod, never had it.

JRE posi mod works every bit as good. I've taken it into the 9's with no problems.

[Merc]

Originally Posted by Supercharged SS

JRE posi mod works every bit as good. I've taken it into the 9's with no problems.

I've chipped teeth off the spider gears in the stock one and the JRE modified one. As far as I'm concerned the stock carrier unit is the weak link and I have two broken diff's to prove it. I believe if I had of put a Trutrac in with the gears, JRE caps and LPW cover I wouldn't be putting in the 12 bolt Hammerhead that I'm in the process of doing right now.

On the bright side my end goal is 650hp NA and with the 12 bolt Hammerhead in my diff issues are over.

[Supercharged SS]

Originally Posted by Merc

I've chipped teeth off the spider gears in the stock one and the JRE modified one. As far as I'm concerned the stock carrier unit is the weak link and I have two broken diff's to prove it. I believe if I had of put a Trutrac in with the gears, JRE caps and LPW cover I wouldn't be putting in the 12 bolt Hammerhead that I'm in the process of doing right now.

On the bright side my end goal is 650hp NA and with the 12 bolt Hammerhead in my diff issues are over.

You shift it yourself, I don't. I think that's where the problem lies.

[Merc]

Originally Posted by Supercharged SS

You shift it yourself, I don't. I think that's where the problem lies.

I do it the old fashion way with a stick. Pumpkin is LS3 M6 and that's probably why I'm hard on diff's. Not to mention 4800 RPM launches.

[Cuda7050]

For what its worth, I thought I would share mainly for the SoCal folks, I got a quote of $1,675 for a TruTrac and 3.91 gear installed in my car from Unitrax of Anaheim. Seems like the way to go for me.

[blazzin1]

Originally Posted by Cuda7050

For what its worth, I thought I would share mainly for the SoCal folks, I got a quote of $1,675 for a TruTrac and 3.91 gear installed in my car from Unitrax of Anaheim. Seems like the way to go for me.

Seems like a "reasonable" price. I would add in the JRE billet caps while you're in there!!!

[IneedAZ]

I decided to start all new...ordered another set of 3.91, new pinion and side bearings, shims, crush sleeve and nut, and the new TruTrac, BMR bushings, and a new place to install it. I know it takes an hour to take out of the car and an hour to install. My guess its another hour on the bench. Then there is the unplanned issue time. So i figure 4 hours total based off my last few removals and installs. New place quoted me $250. They said they gave me the cheaper labor rate for Hot rods, so he is applying that rate to mine. I am so over the cluthes in the factory LSD unit...grinding and popping all the time. Parts and labor around $1300 on top of the $2000 i paid the original place plus 4 trips there and issues each time.