all-trac center diff. question

[tomo]

Just got a '90 all-trac wagon. The center diff. button doesnt make any differance if its on or not. Both front and rear diffs. are always active. New to the toyota scene. Help.

[Deep]

I think the diff button locks torque 50/50 F/R instead of diabling the front or rear. Could be wrong though.

[Floyd]

Hey now,

I have a 92 Corolla Wagen. When I first bought the car - that button (when engaged) did not seem to affect the car. AFter getting it fixed (can't remember the cost) - when engaged you will be in AllTrac mode and therefore you will not be able to reverse the car. I never take the car off road, but it does come in handy when in snow conditions. I recommend getting it checked out if feel that the ALLTRAC mode is not egaging. D in AZ

[awdCorolla]

Actually it depends on if you have a auto or manual transmission as to what the button does. For the 5-speed it's full time AWD, if you press the button, it basically locks the center diff to split power 50/50.

With the auto, it's less like that and I can't remember exactly what it does, but when I was looking through the factory manual it is quite different.

Right now my switch is not working , I have yet to troubleshoot it, any advice?

[Chris Corolla S]

I'll move this to the tech section, maybe some All-Trac Celi guys can chime in....

[REN69]

man.. gotta get me an All-trac wagon! damn weather is bad this week.

[alltrac165]

You can go to
www.alltrac.net
for nothing but alltrac info. I've got an 88 ST165. No button. Maybe someone on the alltrac board can help?

[Morpheus]

Even if it splits 50/50 front and rear how does it control the power between the left and right tires. Thats has got to make a big difference too in the performance. If its just an open differential instead of getting a the best launch possible for example you might get the eqiuvalent of the famous one wheel wonder , but on two axles. I'd think on a roadgoing car like that with a simple locked 50/50 center diff it would just have open diffs on each end. Still advantageous but nothing that's tuned for full benefit of an AWD system.

[tomo]

in my wagon, in the snow, the left rear tire and the front right tire would spin leaving no power to the other wheels. didnt make any diff. if the center diff. button was on or off. Not sure how the center diff. is activated. I can't seem to find a repair manual for a all-trac wagon. I see books for front wheel drive or rear wd. What books are you guys using??

[Morpheus]

Just as I thought. You have open differantials on each side so all the power will go towards spinning one wheel on each axle. The benefit is that now the power is split between 2 wheels instead of one giving you twice as much traction than if the center differential was off. When it is off all your power would be going to the ground through one front wheel. I suppose the benefit of being able to turn it on and off is to save gas mileage when you dont need it on the highway or something, because it takes more power to push both axles and there's more drivetrain mass to overcome.