Someone I respect offered the opinion at one point that an Eaton diffy would be very robust in an 8.8" install. I went to the web site

Performance Products | Detroit Truetrac Differential

Performance Products | Eaton Posi

Any ideas on what determines whether you'd want the Eaton Posi or the Detroit Truetrac?

I'm considering a change now because my LockRite is locked up all the time right now.

 

got a trutrac in my diff,brilliant,no noise on corners and works a treat if ya get a little loose.
And nothing to give ya grief like clutch plates etc.

 

Thank you,
Moderators

 

I've had the Eaton Posi in my Lightning for many years now and it works well; with street tires, drag radials and slicks. It doesn't push around corners and it's completely rebuildable. With that said, I wouldn't hesitate to put in any daily driven truck.

However, given the power mine makes and the type of driving I do, I'll probably install a true-trac if the unit I have now should suffer catastrophic failure. Otherwise, I'll just rebuild it when it's needed and just keep abusing it

 

Thanks for the responses guys.

Do both of these units allow some slippage on sharp turns, or is the Truetrac a complete lockup spool, which is in effect what I have now?

 

Clutch-type limited slips (the generic category name for what General Motors calls positraction) simply create drag between the two tires on an axle. The amount of drag depends on how it's set up and how worn out it is. When the drag is very low (set up very loose or very worn out) it acts pretty much like an open diff. When the drag is very high (recently set up tight) it can act pretty much like a spool (although in reality it might not be able to be set THAT tight).

Gear-type limited slips (Truetrac and Torsen) are more consistent, but less adjustable. If neither tire wants to spin it works pretty much like an open diff, giving the same torque to both tires. But if one tire doesn't want to stay hooked up it will put more torque to the other tire (3.5 times as much in the case of the Truetrac if I recall correctly).

So no, a Truetrac is in no way like a lockup spool. It gives the best differentiating of any traction-aiding differential. It's only functional downside (in addition to cost and possibly breakage, which I hadn't heard before) is that if one tire gets zero traction it will give 3.5 times zero = zero torque to the other tire. For this reason lockers or spools are a better bet for situations like rock crawling where lifting a tire is common. But in most situations when all 4 tires are on the ground the 3.5x works great.

 

They're both designed to slip around corners, however, the Eaton unit is a little more forgiving when it's wet.