Detroit Trutrac or Posi Limited Slip Diff?

[1LE_Justin]

I have some money looking to spend on upgrading my 5th gen 1LE rear diff.
What would be better between an Eaton Detroit Trutrac, or Eaton Posi Limited Slip? Why and whats the difference between either?

[Joe.G]

Most will tell you the TruTrac, I run them in my truck and Camaro, And have used them in other vehicles as well. They are fairly strong and they are smooth with no clutches to wear out. They do prefer non Syn gear oil. TruTrac operates with gears, regular posi has clutches.

[1LE_Justin]

Ok thank you for the response, out of 650 views!

[Joe.G]

You will be very happy with the Trutrac, They are quiet smooth and strong for the application, The Z/28 runs a similar style.

[SS_Dave]

I can only comment on the TruTrac as that's what I put in with a set of 3.91's. I was coming from a 100k mile stock diff. The difference is significant. I remember first time I really was getting on it to see how it would act. At one point, I was getting on a curved entrance ramp. Hammered it and when I grabbed second and hit it again, there was only the slightest wiggle. Very planted and composed. The setup is quiet as well.

[acammer]

Originally Posted by 1LE_Justin

I have some money looking to spend on upgrading my 5th gen 1LE rear diff.
What would be better between an Eaton Detroit Trutrac, or Eaton Posi Limited Slip? Why and whats the difference between either?

TruTrac all the way. Couple reasons. First - it's your only option. See below - Eaton does not have a Posi Limited Slip for our application. BUT - even if they did, a helical LSD is a extremely tough, maintenance free unit.

The Posit Limited Slip is a clutch style LSD, it uses clutches to engage both drive wheels. These clutches are wear items that will change its performance as it wears.

A TruTrac uses helical gears, rather than clutches, to bias power based on load. This is an incredibly strong arrangement that's essentially failure-proof in our application - you'll break a ring gear or axle before you hurt a TruTrac. It's also maintenance free - they don't wear out, or ever require adjustment.

A posi cannot deliver the variability that a helical diff can - if it's adjusted to have a high bias ratio, that will show up under tight turns even with minimal/no load applied. The helical (TruTrac) is completely variable depending on how it's loaded, and so it can be fully open, and then immediately start biasing torque strongly when a load is applied.

We stock the TruTrac here at GPI, and I can tell you that from years in the business, as well as a personal owner, there is no better performing nor stronger option for the factory 218mm differential. If I can help get you setup with one feel free to email me at andrew@gwatneyperformance.com.

EDIT - it's worth noting that the TruTrac supports all available gear options, including 3.91 and 4.10/4.11. I have verified this with Eaton directly, and also have personally run TruTrac diffs on a few different 4.10/4.11 setups.