phattyduck":2bkw2t2g said:
Sluice Box Hero":2bkw2t2g said:
ok, so i did this today, not clutch drop at 6k, but i did get the car to 5k. and nothing, the front end spun and the rear just sat there.
if i put the rear on stands and start to pull the car forward the car pulls itself off the jack stands. this proves to me that it is a fwd car with a tag along rear axle.
now, where can i have this viscous couple rebuilt??? mine obviously is done.
Doesn't prove anything. If your viscous coupler is not working, the car wouldn't move in either case - the 'off the ground' wheels would spin front or rear.
Fix that selector switch...
-Charlie
well, not exactly. the front wheels always have power from the transmission. 100% of the time, just like a FWD car, there is a pinion gear that rotates a bull gear, which is connected to a carrier with spider gears inside, its a 100% normal FWD transmission. what makes it 4wd/awd is coupler for the center diff. there is another set of spider gears attached to the FWD diff that is the center diff. the inside of the viscous coupler attaches the the side gear that is attached to the carrier (the part where the bull gear is attached on the FWD diff)on the FWD diff, this is going to be the left side gear in the center diffs spider gear set. the outside of the viscous coupler (the part where the ring gear for the rear output attaches) it attached to the right side side gear in this set of spider gears. the inside plates of the viscous coupler get power all the time from the FWD diff carrier. the outer plates only get power when there is a difference in speed between the plates, IE, the front wheels are turning a different speed than the rear wheels. now where this gets interesting is the outer plates, or the carrier for the viscous coupler is ONLY powered from the inner plates. when driving straight down a road the inner plates and the outer plates are moving the same speed, so there is effectively no "coupling" happening, if you started up an icy hill and the front tires started slipping then the change it speed would tighten up fluid and start to transfer power to the rear wheels until they were traveling the same speed again, at which point, the coupler would "unlock".
if you were to set the front of the car on jack stands and the rear on the ground the inner plates would spin with the front diff since they are 100% conntected to the front diff carrier all the time. and since the outer plates are 100% connected to the rear wheels (well, the ring gear of the ring and pinion that make up the rear output of the "transfer case") they will want to stay still, just like the rear wheels, this is of course until the viscous fluid begins to heat up and transfer power to the outer plates in essence creating force on the rear wheels. if the fluid is trashed, or leaked out, then the rear wheels would just sit there and do nothing while the fronts spun normally. now, if one were to lift the rear of the car in the air and set the front tires on the ground the car would pull itself off the stands immediately just like a normal FWD car, because, it has a normal FWD diff that gets power 100% of the time from the transmission.
basically what im getting at is that you could NEVER, and i mean NEVER EVER NEVER EVER get the rear wheels to spin without the front wheels spinning faster. unfortunately this is a FWD car with a RWD assist.
the way many other AWD cars get a rear bias is with either clutches and gears, or the front wheels are power through a viscous coupler rather than the rear wheels.
if toyota wanted to get this correct they would have built the unit backwards. the transmission pinion gear would have driven a bull gear that shared the carrier with the outer blades of a viscous coupler and with the ring and pinion for the rear output to the rear wheels. and the carrier for the front carrier would have been driven off the inner blades of that coupler.