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Old 08-11-2013, 10:23 AM   #1

DrkPhx's Avatar
Drives: 2013 Triple Black ZL1 / 2006 TB SS
Join Date: Feb 2011
Location: MN
Posts: 2,075
Install and Review: Eaton Detroit Truetrac For The 5th Gen Camaro SS

I found this on and thought the SS guys might be interested in the installation and review. They installed it on bolt on and cammed 2010 SS. Pretty good article.

Technology has given late-model muscle cars like the 5th Gen Camaro unprecedented access to bolt-on horsepower. Unfortunately after discovering just how easy it is to add gobs of rear-wheel-horsepower many enthusiasts also find how quickly the OEM limited-slip differential’s ability to transfer torque can be surpassed. It’s about then that an age-old racers axiom is rediscovered; “The only power that really matters is the power you can get to the ground,” or put another way – “Spinning ain’t winning.”
Luckily there are already a few performance differential options for powerful late models that see regular racing duty and need to use that horsepower and torque to get the car moving in a hurry. In fact, Eaton has even taken their respected Detroit Truetrac and adapted it for use in the new Camaros, and offers a great balance of streetability and hardcore performance. Follow along with us as we review the technical details of the 5th Gen Detroit Truetrac, and install one (Part #912A686) in a street/strip LS3 powered 2010 Camaro SS.

About The Eaton Detroit Truetrac For 5th Gen Camaros
Because of the Truetrac’s durability and versatility, you’ll find it used in all different types of racing and high performance applications.” -Barney Bwozdz, Eaton
The Detroit Truetrac is really nothing new. Its time-proven operation has been the same for decades, but has been steadily refined by the engineers at Eaton as new technology has allowed. “The 5th gen Truetrac is essentially the same internally as what you might find installed in a 12-bolt in a ’69 Camaro running at the drag strip,” says Eaton’s Barney Gwozdz. “This is just the design specific to the envelope GM gave us with the 5th gen Camaro’s differential.”

Instead of using clutch packs like a typical limited-slip differential, the Truetrac uses a helical gear design to transfer the engine’s torque equally to both wheels, or to the wheel with the most traction should tire spin occur. “The Truetrac has the ability to transfer up to 70% of the torque load to the wheel that has the most traction,” says Gwozdz. “Let’s say you have one rear wheel on wet grass, and the other on dry concrete and you rev up the engine and sidestep the clutch. Obviously there is zero rolling resistance on the tire in the grass and it is just going to spin. However, because of the Truetrac’s biasing capabilities it will send 70% of the torque to the wheel on the concrete and move the car forward.”

Inside the Truetrac are three sets of interlocking pinion gears that span from one main axle gear to the other. The gears will be completely locked up when both tires have the same amount of traction, but will still seamlessly allow the outside wheel to spin faster as the car goes through a turn on the street or a road course. No popping, clunking, or jerking. Check out the video below for a visualization of how the Truetrac’s helical gears operate.

The Truetrac is at home on the street, but it is built durable for racing. “What we try to do is add as many pinion gears as we can inside the envelope we have been given to work with,” says Gwozdz. “The more pinion gears you have, the better they can dissipate the torque load. The 5th gen Camaro Truetrac is a three-pinion design so it’s very heavy-duty.” Eaton continues the heavy-duty design on the outside of the Truetrac as well. They wrap the helical gears in a rigid steel case, rather than a typical sand-casting to ensure that everything stays together even under the rigors of racing.

Eaton did have to make a few small changes to adapt the time-tested Truetrac to the new Camaro’s independent rear suspension. “The agility and articulation allowed by the new IRS is great, but it did have some special considerations in our design,” Gwozdz tells us. “For example, the pilot on the axle shaft as it enters the differential’s bearing journal is unique. So we had to make our own provisions to pilot the half-shaft into the Truetrac.”
The 5th gen Truetrac is designed to work with stock and aftermarket 32-spline rear axles, and will also accept any 218-milimeter ring and pinion set with the same flange height as the stock gear set.
Another unique consideration for the new Camaro is that it does not use synthetic gear oil like the stock differential, or any kind of friction modifier or additive for that matter. The reason for this might seem strange, but synthetics gear oil and friction modifiers are actually too slippery for the pinion gears in the Truetrac. They need a small amount of resistance to bite together properly, so Eaton designed the Truetrac to work with plain ‘ol conventional 80W-90 gear oil.

The Test Car: Street and Strip 2010 LS3 Camaro SS
Our test car might look familiar to those of you who frequent our site on a regular basis; that’s because it’s Jose Lugo’s street and strip beast dubbed “Killer Bee”. The Camaro is a 2SS/RS with an LS3 that has been treated to Doug Thorley long tube headers, an Airaid MXP cold air intake, and a COMP camshaft to really wake things up. The cam specs in at 227/239 duration, .629/.623 lift, with a 114 LSA, and the whole combo puts down a very respectable 475 horsepower and 430 pound feet of torque to the rear wheels.
The Camaro sees a lot of drag strip duty in addition to serving as Lugo’s daily driver, and has run as quick as 12.31 at 115 MPH on drag radials. In the search for a twelve-flat timeslip, Lugo opted to have the guys at central Texas’ Easy Performance install the Detroit Truetrac along with a set of 1LE Camaro 3.91 gears and BMR’s polyurethane differential housing bushings while they were at it.

5th Gen Camaro Eaton Detroit Truetrac

Three Pinion Helical Gear Design
Durable Hardened Steel Case
Works with Stock or Aftermarket 31-Spline Axles
Locks Wheels Together in Straight Line
Automatically Transfers up to 70% of Torque to Wheel with the Most Traction
Street Friendly and Quiet Operation
Uses Standard Gear Oil (No Synthetic or Additives)
DrkPhx is offline   Reply With Quote
Old 08-11-2013, 07:25 PM   #2

Drives: 2SS/RS CGM LS3
Join Date: Aug 2009
Location: NJ
Posts: 1,560
This is the same set up as I got from JRE, except I paid for the LPE 3.91's before the 1LE gears were available. I cant wait to get back to the strip I the fall.
SOLD Vengeance stage I cam (442rwhp/412rwtq) / CAI intake w/ADM race scoop / Dynatech LT's / ATI udp / JRE tuned / Eaton Posi LPE-JRE 3.91's / L99 Corsa / Whiteline Sways & Bushings / UMI Trailing Arms & Toe Rods / ZL1 wheels / NT05 275/315
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