Quote:
Originally Posted by mywife's4runner
Also when in 4low why in the world would you want atrac off. If it is off then you would have open diffs right? So why leave it off?
|
I can answer this from recent experience. I have a 2010 SR5 4x4. I took a ride out in a national forest where there was 10-12" of fresh snow ontop of a relatively rough dirt trail. The trail was slightly off camber with a steep dropoff at one side.
I had the vehicle in 4L with ATRAC engaged, and the car would every so often start turning to the right toward the dropoff even though I was steering to the left. I about crapped in my pants a few times. I noticed that if I let off the gas when this happened it would straighten up.
When I got out to inspect the conditions, I found that there was ice under the snow only on the right side of the trail. The computer was sensing the wheels on the right slipping so it would brake only that side of the vehicle to transfer power to the wheels that were not slipping which would push me right. Once I turned ATRAC off everything straightened out just fine.
In my opinion ATRAC should only be used when already stuck and one wheel spinning or atleast in locations where sideways movement of the vehicle wouldn't have any serious consequences. Although Toyota markets it as a true replacement for a locking diff, it does not perform similarly in all conditions. If I would have had a true locking diff in the situation above, both rear wheels would spin whether they had traction or not, so I wouldn't be pushed to one side (or not nearly as much).
An ARB rear locker is in my longterm plans.