Traction 4 wheel drive

[karenlyn]

Welcome to TBN. Question is a little vague. What are you wanting to do with your 4WD?

does the pto have to be engaged for the 4 wheel drive to work? And if the front axle fluid is low will this prevent it form working? Thanks for any help. Karen

[RaydaKub]

does the pto have to be engaged for the 4 wheel drive to work? And if the front axle fluid is low will this prevent it form working? Thanks for any help. Karen

1) No. they are independent.
2) No. But it will likely prevent it from working several years from now.

Just add the front axle level check to your routine and top it off if necessary.

[LD1]

4WD does not mean all 4 tires spin / get power, one back wheel will get power, and one front wheel will get power.

Here we go again

All wheels are powered in 4wd. 2 wheels are powered in 2wd.
larry

when ya get stuck in the mud, one front wheel and one rear wheel with just 4WD is engaged. can and will just spin in the mud, leaving the other 2 wheels barely spinning or not spinning at all.

if a tire is not spinning, to me it is not getting power. at the differential. more so when you are stuck in the mud. or on ice / in snow, and ice skating on 4 tires.

Yes, the non spinning wheel is not delivering power, technically, since mech power requires motion. But, that wheel is delivering forward force = to that of the spinning wheel.
larry

Not quite.

With an open differential both wheels are ALWAYS putting the same power to the ground. It's not "three wheel drive" or "one wheel drive". One wheel can be spinning and one can be stopped, but they are experiencing the same torque through the drive axles and putting the same driving force to the ground.

Open diff means equal torque and unequal speed.
Locked diff means unequal torque and equal speed.

So when you lock the differential, both wheels will spin, but one is experiencing more torque and driving the tractor with more force.

In four wheels drive and the vehicle turning a corner, there is slipping against the ground because the front and rear axles are making a different circle, or traveling a different distance. This is with no center differential in the transfer case to allow different speeds between the front and rear axles. So there is binding, but it's not a big deal unless the tractor is heavily loaded and on dry pavement.

Watch this video for better understanding:

Around The Corner (1937) How Differential Steering Works - YouTube

How we managed to hijack poor karens thread??

Karenlyn: Might you gives us some symptoms as to why you tink the 4wd is NOT working? What is the tractor doing? Is one of the front tires spinning?

And it is not a good idea to run the front axle low EVEN if you keep it out of 4wd. Just because they arent being driven by the driveshaft, the ground is still causing the axles/bearings inside there to spin. And without oil, it wont last long.

[Raspy]

does the pto have to be engaged for the 4 wheel drive to work? And if the front axle fluid is low will this prevent it form working? Thanks for any help. Karen

Maybe a bit more information would be helpful. Are you having trouble getting 4WD engaged? Or are you finding that not all the wheels "spin" when you get stuck?

The PTO and the fluid level don't prevent 4WD from engaging.

Sorry, but I'm not understanding your question very well. What seems to be not working?