How do I test the AWD?

[MrWhoopee]

I've searched, but haven't found the answer. I know how to do it in my Hondas, raise the car on a lift (all 4 wheels), start the engine, put the car in first gear and set the e-brake. If the engine dies, the rear wheel drive is working. I assume this will work for a Subaru, but I'm not sure. Since I am shopping for a Subaru and I know that many people do not pay attention to keeping the tires matched, I would like to be able to test the AWD, preferably without having to take it to a shop.

 

Please enlighten me.

[johnceggleston]

what trans?

 

i'm not sure an auto trans will die if you rest it as described.

a manual probably will.

but don't test it for too long since it will wear the viscous coupling.

 

what makes you think the AWD is not working.

 

more often than not, subarus fail in a torque bind mode,

meaning not FWD, but locked FWD.

like a 4wd truck with locked hubs on dry pavement.

 

what is your car doing?

what is your car not doing?

 

year, model, trans, miles, ?

[Fairtax4me]

Manual trans is pretty easy. With the trans in Nuetral, jack up one wheel at a time, spin the wheel. Good AWD the wheel should spin but with a LOT of resistance. If the wheel spins easily the center viscous coupling is worn out.

 

Auto you put the car on jack stands with all 4 wheels off the ground. Put it in drive and let the wheels spin. All 4 should spin. Set the parking brake and all 4 should stop, or the rears should stop and the fronts should spin very slowly.

Now put a fuse in the FWD fuse holder on the passenger strut tower. The rear wheels may spin but much slower. Set the parking brake and the rears should stop, fronts should keep spinning freely.

[MrWhoopee]

what trans?

 

i'm not sure an auto trans will die if you rest it as described.

a manual probably will.

but don't test it for too long since it will wear the viscous coupling.

 

what makes you think the AWD is not working.

 

more often than not, subarus fail in a torque bind mode,

meaning not FWD, but locked FWD.

like a 4wd truck with locked hubs on dry pavement.

 

what is your car doing?

what is your car not doing?

 

year, model, trans, miles, ?

I don't have one yet. Trying to avoid buying one with problems.

[ford'ssubaru's]

Do 360's in the snow..........Tested tested sat.....LOL

[Gloyale]

i'm not sure an auto trans will die if you rest it as described.

a manual probably will.

but don't test it for too long since it will wear the viscous coupling.

 

I don't think this would kill the engine of either trans.....even with proper functioning AWD.

 

The Automatic might.....if the TCU detects enough wheels speed difference, and locks the Hydraulic transfer to the rear end.  But then again may unlock it slightly as it senses the engine idle dropping too low.   IDK

 

A manual definately won't kill the engine.  You'll just sit there with the front spinning.  At least at first it won't....the center diff is open....so the front will spin and the back will do nothing until the Viscous Coupler heats up and locks up.  This isn't very good for the center diff though......I've had a couple fail to let go then they stay

"locked" when pushed too hard.  They heat up and you get transfer, but then they can stay that way so in my opinion it's best not to make them slip too much for too long.

 

 

I would say the best test would be to find a gravel or dirt parking lot and floor it. 

 

If the front spins but nothing in back then it doesn't work......if the back kicks in after a slight slip from the front that is normal for the automatic.

 

Manual you should feel all 4 right away.

Edited December 22, 2013 by Gloyale

[johnceggleston]

if there is snow on the ground, or wet grass or similar,

i have tested mine by sitting side ways on the hill,

and punching the gas.

when the wheels spin, front or rear, that end of the car will side slip down the hill.

i did this in wet leaves.

 

this is not a perfect test, obviously.

[CNY_Dave]

Buy a 3.0... if the AWD doesn't work when you stomp on the gas from a stop the fronts spin like mad

[johnceggleston]

my 95 lego would chirp the tires in FWD.

[Bushwick]

Mine, even with some weight in the rear and an auto, will easily spin all 4 on snow covered roads and presumably gravel, but you need to punch it and hope it kicks down. I've been able to do this going about 30-35 on snow slick roads (meaning there was just a coating on the road). It'll be pretty clear if the AWD is working or not. Also, on slick or gravel roads, the rear will kick out like a RWD car, but if you stay in it (keep pressing the gas pedal and steer into the direction the rear is pointing) you can pull out of it as the front tires are pulling you onward. Oversteer is pretty pronounced in hard turns as opposed to forced FWD.

 

To test if FWD is working as intended, on some cars (dunno if newer cars have it) there is a "FWD" connector up against the passenger side fire wall. You can either stick a fuse in there (it's a cap that covers a fuse receptacle) or jump with wire and a switch. With a fuse in there, it forces FWD only and disengages the rear. I ran mine in forced FWD for a day once. It'll easily spin the fronts on wet pavement (thanks to the steep 4.11's) and car behaves VERY differently in turns, and wheel spin with the front moving is evident, not to mention the engine revs quicker while moving as it only powers the front tires. It'll also understeer pretty noticeably.