Detroit Truetrac vs others on rain/ice/snow - Opinions please
Please contribute with your first hand experience. I have searched/read several of the threads on this board, and this is meant to be a "fact-finding" thread. It will become more useful once the engine is running properly again.
1988 Ranger XLT, Super-Cab
2.3L, 5sp, 4x2
Rear axle - 7.5" 28 spline open diff (forgot the gear ratio). I am willing to swap rear-ends to an 8.8" if I have to.
THIS WILL NOT BE USED OFF-ROAD OR TRAILS. The most off-roading I do is to roll over something, curb, snow drift, etc..... Only driven on the street. I like the idea of the Detroit Truetrac (like the one Eaton makes), that gives you lock-up when you need it and limited slip when you don't.
What I want is more traction in the rain/ice/snow. Particularly when I am parked, or trying to move up a hill. Some times when I park I have to park on a hill or against a curb. Snow may fall or water freeze, it doesn't matter the same thing happens as you might expect. Right rear spins and you go nowhere. I had a situation last year where my right side was on ice in the gutter and the left side was on bone dry pavement, and I wasn't going anywhere. Before you all say "get sand bags", I have 5 of them in the bed right now. Yesterday I was unable to get up a hill after trying for 2-3 min(like several other folks too), so instead of blocking traffic I shifted into reverse and hopped over the median to go down the hill the other direction and take a different route. The look on the guy's face behind me in his Mercedes as my front end swung past his was priceless.
One thing you must keep in mind when running any kind of locking differential on ice is this. While there is a great traction advantage, care must be taken when turning a corner on ice. While in an open differential, one wheel will break lose first, the other will ad some form of stability because it is not spinning. Once both wheel start to spin as in a trac-loc you will be on a wild ride for sure. A lot of friends of mine that do a lot of side hill driving on slippery slopes, say that an open diff will hold you on the hill better that a locking diff. That said, if you are prudent in your driving techniques, you can make a locker work to your advantage.
phil6608 - Yea, I am aware Ford L/S unit is much cheaper for the part, but they are the same price to have installed. Also, there is no parts in the Truetrac to wear out like the clutches in a regular L/S unit.
WarWagon - See that is the nice thing about the Truetrac, it isn't a full locker like you would think. It will function like an open diff until one of the wheels starts to slip, the Truetrac will shift the power back and forth to the wheel with the most grip. According to another member you can fool the unit into working like a locker if you apply a little e-brake before you go.
And yes I know what it is like to drive in the snow in my old Pontiac that has a locking 3.73 rear, and WAY more torque than necessary.
I forgot to ask this earlier, but some of you may know the answer.
I realize the 7.5" 28 spline rear-end is weak compared to the others, but considering this is a street truck, will adding the TrueTrac increase the possibility of a breaking parts like axles, ring gear, etc....? I know adding a "locker" or "lunch box" or some others can stress the axles pretty good, and lead to broken parts.
My opinion is that no more needs be said. Detroit TrueTrac all the way.
Doesn't wear out. Doesn't slop up the drive line. Doesn't produce torque steer between acceleration and engine braking. Doesn't get the truck bucking if you change from accelleration to engine braking, or vise-versa, in a turn. And it keeps all four tires working for you much better than open differentials.
That said, the only other consideration is cost. Lunch box lockers are considerably cheaper to purchase and install.
[...]will adding the TrueTrac increase the possibility of a breaking parts like axles, ring gear, etc....?
Not to any appreciable amount. Unlike an open differential, Its torque biasing will allow greater than 50% of the torque coming down the drive shaft to be delivered to a single axle shaft. However, since you're on the road and since torque biasing doesn't occur until there is wheel slippage, the only way you're going to deliver high torque loads to a single shaft is to get one tire spinning on snow and the other coming into contact with pavement - and giving it some go pedal - street driving with a TrueTrac generally won't push any more torque down a shaft than an open differential.
One exception: Turning sharp corners will engage torque biasing as well, delivering a proportionally higher load to the inner wheel than to the outer. So if you have enough motor and enough traction, and not enough axle, you could potentially snap a shaft when turning where you might not necessarily do it with an open differential.
In a nut shell, take it easy and you'll never have a problem.