Locker vs. Limited slip

tjkj2002 · **Posted:** Tue Mar 25, 2014 10:34 am

Rich wrote:

Maybe I should clarify.

The TT acts just like an open diff when one tire has little to no traction. Meaning ALL the power goes to that side and spins, while the traction tire just sits. IF there is a bit of resistance (torque) on that off-weighted wheel, it will tighten up and provide traction for the plated tire. This is exactly were the "parking brake trick" comes into play. Best demonstration was when AM General brought in their reps when we first took delivery of the M1114's in '00.. a log under opposing corners with the truck in gear idling away and lifted tires rotating freely. Instructor started to drag the brake and truck drug itself off the logs in short order; more than a couple months playing in the rock piles of the Mojave Desert in my M1026 and M1114 sealed my love for the diffs. In the untold miles I flogged those trucks for, I only blew one diff... and that was all my fault. When you head into a corner a bit too hot, and drop the throttle with the inside tire off-weighted, 90% of the time the diff will act open. It provides much better traction when you have sane and stable exit speeds, good weight transfer, and smooth... all the things you are supposed to be doing on the exit. Nothing else, it encourages the driver to do things right.

As for slipping sideways in the snow and ice... My avatar is my old '00 XJ doing about 50mph on a skid pad in 11" of snow or so on a sheet of ice... DTT rear was present ;-)

There are times I miss that XJ.

Just to clarify the HMMWV never came with DTT's ever,they have Torsion diffs which are a little different and yes "the brake trick" was what made them "lock" also.

Rich · **Posted:** Tue Mar 25, 2014 12:27 pm

tjkj2002 wrote:

Just to clarify the HMMWV never came with DTT's ever,they have Torsion diffs which are a little different and yes "the brake trick" was what made them "lock" also.

Torsen T-1 is a helical-gear, torque-biasing, limited slip diff
Eaton TrueTrac is a... helical-gear, torque-biasing, limited slip diff

I should have said... "...sealed my love for helical-gear, torque biasing diffs."

Pedantic much?

tjkj2002 · **Posted:** Tue Mar 25, 2014 12:38 pm

Rich wrote:

tjkj2002 wrote:

Just to clarify the HMMWV never came with DTT's ever,they have Torsion diffs which are a little different and yes "the brake trick" was what made them "lock" also.

Torsen T-1 is a helical-gear, torque-biasing, limited slip diff
Eaton TrueTrac is a... helical-gear, torque-biasing, limited slip diff

I should have said... "...sealed my love for helical-gear, torque biasing diffs."

Pedantic much?

The DTT and Torsion are not the same and operate different.

The DTT acts open and has a torque bias of 3.5:1.The Torsion constantly is biasing torque between the 2 wheels and is offered in either 2.5:1 or 5:1 bias(max rating).There construction is different,the Torsion does not use helical cut gears since you can't constantly bias torque with helical cut gears like the DTT uses which does not constantly bias torque.

Rich · **Posted:** Tue Mar 25, 2014 12:53 pm

tjkj2002 wrote:

...the Torsion does not use helical cut gears...

Quote:

Unlike conventional speed sensing, limited-slip differentials, TORSEN T-1... the T-1's patented INVEX gearing system is designed to perform for the life of the vehicle.

Quote:

How Torsens work... the element (also known as satellite) gears connect with the spur gears in a modified crossed axis helical gear mesh. Also known as an Invex gearing arrangement...

INVEX just adds a straight cut gear at the ends of the primary helix. That doesn't change the fact that, fundamentally, the Torsen T1 is a helical-geared, torque-biasing, limited slip diff.

ATXKJ · **Posted:** Tue Mar 25, 2014 5:11 pm

3D animation of Torsen
http://www.youtube.com/watch?v=Z9iPqIQ_8iM

3D animation of TrueTrac
http://www.youtube.com/watch?v=LTXvH3T8Bsg

They both use gears.....but they're different.

personally I've got front and rear TrueTracs - they work great

Rich · **Posted:** Tue Mar 25, 2014 7:10 pm

yep, both helical-geared.

Locker vs. Limited slip

Who is online