In the example given with one wheel jacked up the torque is split evenly between both wheels. It takes little torque to spin the wheel that is off of the ground. That same amount of little torque is also applied to the wheel that is on the ground. It is not enough torque to move the truck, therefore the truck goes nowhere.
100 series problem
- Thread starter davefj40
- Start date
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So with one wheel off the ground and in 1st gear revving at say 2500rpms where is all that power going?
What is being applied to the tire on the ground is equal to that of what it takes to get the other wheel to spin. The rest is wasted out through the spinning wheel.
What is being applied to the tire on the ground is equal to that of what it takes to get the other wheel to spin. The rest is wasted out through the spinning wheel.
With an open differential, one wheel in the air spinning, one wheel on the ground stationary, the torque going to each wheel is equal.
Power = torque x rpm. The stationary wheel is providing no power, as its rpm is 0. The torque between axles still remains equal. That is what the gears in an open differential do, apply equal torque to both axles, while allowing permitting each axle to rotate at different rates.
What mechanism within a open differential do you believe would distribute torque unequally between the axles?
Power = torque x rpm. The stationary wheel is providing no power, as its rpm is 0. The torque between axles still remains equal. That is what the gears in an open differential do, apply equal torque to both axles, while allowing permitting each axle to rotate at different rates.
What mechanism within a open differential do you believe would distribute torque unequally between the axles?
our engine at 2500 rpms lets say puts out 125 hp and 160 ftlbs torque. If half of that is going to each wheel regardles of traction then why when 1 tire is off the ground we get no movement?
Power = torque x rpm, on the side that is not moving, 0 rpms, there is no power, it's all on the other side that is rotating.
Power = torque x rpm, on the side that is not moving, 0 rpms, there is no power, it's all on the other side that is rotating.
[quote author=landtank link=board=2;threadid=15637;start=msg148960#msg148960 date=1083468301]
our engine at 2500 rpms lets say puts out 125 hp and 160 ftlbs torque. If half of that is going to each wheel regardles of traction then why when 1 tire is off the ground we get no movement?
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Let's say the engine is capable of producing 125 hp and 160 ftlbs at 2500 rpm. Just because it is turning 2500 rpm, does not mean it would be producing that amount of hp or torque.
With a wheel off the ground and spinning, it require very little torque to spin. Not much torque at the axle, not much torque at the driveshaft, not much torque in the transfer case, not much torque in the transmission, and not much torque at the crankshaft, even if the engine is turning 2500 rpm.
If you were going up a hill, with the gas peddle all the way down to the floor, and the vehicle speed was constant, and the rpm was 2500, then your engine would be producing your (for this example) hypothetical 160 ftlbs of torque.
Look at how the differential pinions in the differential carrier engage the bevel gears which engage the axles. Both axles are subjected to the same, balanced input from the differntial pinon gears.
our engine at 2500 rpms lets say puts out 125 hp and 160 ftlbs torque. If half of that is going to each wheel regardles of traction then why when 1 tire is off the ground we get no movement?
...
[/quote]
Let's say the engine is capable of producing 125 hp and 160 ftlbs at 2500 rpm. Just because it is turning 2500 rpm, does not mean it would be producing that amount of hp or torque.
With a wheel off the ground and spinning, it require very little torque to spin. Not much torque at the axle, not much torque at the driveshaft, not much torque in the transfer case, not much torque in the transmission, and not much torque at the crankshaft, even if the engine is turning 2500 rpm.
If you were going up a hill, with the gas peddle all the way down to the floor, and the vehicle speed was constant, and the rpm was 2500, then your engine would be producing your (for this example) hypothetical 160 ftlbs of torque.
Look at how the differential pinions in the differential carrier engage the bevel gears which engage the axles. Both axles are subjected to the same, balanced input from the differntial pinon gears.
Seems like your saying that without load the is no power.
As I went to bed last night I was thinking this thread has the same feel as that one a little while ago about reading conductivity of the radiator fluid. You weren't part of that one too, were you?
I'll admit that I might not be expressing myself correctly but by your own equation as the rpms change so does the power.
The horse seems to be dead to me and I'm not really interested in turning it over to start beating the otherside. So i'm just going to let it lie and hopefully this thread will get back on track with the guys original problem.
As I went to bed last night I was thinking this thread has the same feel as that one a little while ago about reading conductivity of the radiator fluid. You weren't part of that one too, were you?
I'll admit that I might not be expressing myself correctly but by your own equation as the rpms change so does the power.
The horse seems to be dead to me and I'm not really interested in turning it over to start beating the otherside. So i'm just going to let it lie and hopefully this thread will get back on track with the guys original problem.
Power is a measurement of work. It is correct with no load there is no work being performed.
In my view, the value of this site in large part accrues from the sharing of accurate information. I take care to post information that I believe is correct, and am glad to explain the basis of my reasoning.
In my view, the value of this site in large part accrues from the sharing of accurate information. I take care to post information that I believe is correct, and am glad to explain the basis of my reasoning.
The calculation for work is as follows
Work = Force X Distance
Since the vehicle isn't moving, the distance value = 0 meaning no work is being done.
The reason for no movement is that from the formula
Power = Torque X RPM the tire on the ground is not turning, the RPMs = 0 and has no power.
So all the power is going to the wheel off the ground since it is rotating.
again it is not a 50/50 split
Work = Force X Distance
Since the vehicle isn't moving, the distance value = 0 meaning no work is being done.
The reason for no movement is that from the formula
Power = Torque X RPM the tire on the ground is not turning, the RPMs = 0 and has no power.
So all the power is going to the wheel off the ground since it is rotating.
again it is not a 50/50 split
I have stated that an open differential equally splits torque to each axle. I never said, nor implied, that the power distribution is equally split. I posted the formula for calculating power to clarify the distinction between torque & power.
I agree the power distribution will be equal only if both wheels are turning the same speed, but for all pratical purposes the torque remains equal, even when the tires are turning at different speeds.
You are correct that with one wheel spinning, and the other wheel stationary, that all of the power is being distributed to the wheel that is spinning.
I agree the power distribution will be equal only if both wheels are turning the same speed, but for all pratical purposes the torque remains equal, even when the tires are turning at different speeds.
You are correct that with one wheel spinning, and the other wheel stationary, that all of the power is being distributed to the wheel that is spinning.
So Dave, what's the final diagnosis????????
R
robbie
Guest
I see you guy are having fun again. Any how the 100 series has a few different systems on board and it helps to know what is in the vechicle. There is the all open (all diffs open). I have not seen any 100 series with the Viscous coupler nor is any reference to a VC in the FSM. Some 100 series have a Limited slip in the rear some do not. Some have a electric locker in the rear and after 2000 there is either open with LSD or traction control. So you can see in 2000 model year it could have some different systems on board. This particular problem could be hard to diagnosis if you do not know the systems. Hopefully the Dealer has some techs that are up on Landcrusiers. I have no guesses that have not been stated. THe IFS is simliar in front to a 80 series in that you have a diff and cv's and axles shafts. the CV are similar to the birfields. So the front is a naked 80 series front axle that is a little stronger on the birfields and weaker on the diff.
later robbie
later robbie
My Guess would be a broken front diff. More specific few teeth missing from the ring gear. To the best of my knowledge the 100 does not have a VC (my 99 with a rear locker does not have VC) and this is why all 100 have a CDL switch. The front diff on the 100 is known failure point and it will cause the truck to make grinding noises and come to a stop if the broken part of the ring is against the pinion. I do not have an explanation why at the end the truck will not go even if you have the CDL switch engaged.
Doron.
Doron.
- Thread starter
- #33
the last i heard was the truck wasn't able to move at all no matter what they tried but i haven't talked to them since. the people are clients of my wife's and called me because of my obsession with toyota's 
i told them to call me back when they find out what they dealer says so i can post it up here for future reference. maybe i'll give them a call today if i can find the time.
i do know the truck is used to tow a horse trailer and they do regular maintenance on it. not 4wheeled or abused.
dave
i told them to call me back when they find out what they dealer says so i can post it up here for future reference. maybe i'll give them a call today if i can find the time.
i do know the truck is used to tow a horse trailer and they do regular maintenance on it. not 4wheeled or abused.
dave
Dave,
If they tried to back up with the loaded horse trailer, especially against some resistance, they could have broken the front diff. At any rate, since use my truck in remote areas sometimes by myself, I am very interested in the failure points of the 100. Please keep us posted as to the result of this case
Thanks, Doron.
If they tried to back up with the loaded horse trailer, especially against some resistance, they could have broken the front diff. At any rate, since use my truck in remote areas sometimes by myself, I am very interested in the failure points of the 100. Please keep us posted as to the result of this case
Thanks, Doron.