rodC4S

How do you conclusively test the AWD i.e. make the front wheels spin/do something to indicate they are being driven?

I have read several threads in the archives but still there seems to be contradictions in opinion on correct function of AWD.

One guy had his car on snow and no front wheel spin. Another guy said he put the rears on grass and no spin.

Some say this is OK and then others say not OK.

How can you really tell. ? Seems to me that if you put rears on a grass slope and fronts on level concrete and get the rears spinning that you should get the front pulling the car forward, or is this a dumb idea ?

thanks

ROD

Phil

put it on a lift (with someone in the car) have that person let the clutch out...and see the front wheels turn round and round.

User 4621

If you live in 'Noogie, head east about a hundred miles to Deal's Gap, and drive it with the windows down. You'll feel and hear the front tires putting power down on tight corner exits.

Not scientific, but a lot of fun.

Skytop

Drive on a very icey winding highway road way up on a high mountain cliff. If the all wheel drive works please tell us how great it was. If we don't hear from you, we will know it was not operating the way it should.

JimBob Jumpback

Bubba Rodcee,

sinse yall be anudder southern bubba like ol JimBob, i iz a gonna tell yall da sekrete ta doin dis an it be savin yall a hole buncho monee.

yall park yur porch kar on yalls lawn wit da rear tires on da grass an da front tireds on da sideywalker a pointen da kar at yalls howse. put it in geer an yall try ta asscelerate reel hard. ifn it wont be goin, den yall kin spent da monee on fixn d kar. if it goes, den yall shoold be spendin da monee on fixin da front o yall howse.

pert simple, hey bubba?

Yur Fren,
JimBob

Skytop

Only kidding! ;-)

The good ol' boys...

Jimbob, that sound perty scientistic. We aint got no houses though. Does that work good with trailers too?

rodC4S

Ok,

Pete, had some fun at the airport ramp today, tests inconclusive in my mind, your idea would be fun though.

Phil, even if the coupling is broke you would likely get some friction turning the front wheels. Dont know if this would prove its working under load.

So, I tried the test suggested in one thread, jacked one front wheel off the ground (all three others on ground). Now turning the front wheel by hand should turn the diff and then in turn the drive shaft to/from the viscous coupling and if the coupling is functioning, there should be resistance but the wheel should turn slowly. If the wheel turns freely then the coupling is shot.

Ok so mine turns slowly but, the question is how slowly should it turn and if you try and turn it faster should the resistance increase or stay similar. Granted the fluid is not really getting hot doing this, but mabye right after a drive we would get different results.

What do you viscous knowlegable folks think ?.

If a fellow C4S owner or two would care to try this we could compare notes and mabye we could have a standard test procedure for all us new car owners who seem to think the same thing about their AWD..

Phil

Rod,
While the car is on the lift, you could stop one of the front wheels with your hands....I think you will see the other front wheel spin faster.
I do know of one person that tried to stop the rear wheel with his hands... From what I remember, it was NOT a good Idea

rodC4S

Phil,

Thats because the front axle has an open (not limited slip) diff. All you are doing is causing the other fron wheel to spin twice as fast. To test with your method, one front wheel would need to be stopped from turning and then if you tried to stop the other front wheel you should not be able to do so or at least their should be a lot of resistance. Again the question is how much resistance is normal ? .

By the way, You cant stop a back wheel because that axle has a LSD (different from Viscous coupling but similar effect) which effectively joins the two rear wheels like a solid axle.

graham_mitchell

If you really want to test whether the 4WD mechanism is within spec, it's all in the workshop manual

rodC4S

guess i will have to get one. care to enlighten us in the meantime ?

graham_mitchell

ok, just this once!

see http://www.international-man-of-myst.../4wd_check.gif

and http://www.international-man-of-myst...wd_check_2.gif

Specialised equipment is necessary

rodC4S

Graham,

Thanks ! this at least confirms my theory on how to test. Now if i could figure out what 500N felt like i could apply it to my testing method of turning a front wheel.

Roddy

graham_mitchell

How will you rotate the rear wheels at the correct speed? You need a dyno to do this properly not the engine, afaik.