4x4 feels like E brake is on??
04-29-2012, 02:50 AM
#11
You're kinda on the right track. The wheels need to spin at slightly speeds when turning. Thus on a high traction surface (pavement) the part-time transfer case such as the one in the f-150 cannot very the speed of the wheels getting torque between the front and wheel axle. The fact that the wheels are traveling at the same speed is what causes the hopping and chirping.
Full-time transfer cases such as the NV-241 select-trac and NV-249 quadra-trac 4wd tranfercases in the Cherokee and grand Cherokee use a viscous coupler that allows for the differentiation in speed. However anyone who as aggressively tried to wheel a quadratec system that hasn't added a locker or limited slip will tell you that you can quickly end up with a one wheel drive Jeep when you start lifting tires off the ground.
This is the same reason I opted for a detroit auto-locker in the rear axle of my Jeep rather than a spool. The detroit automatically unlocks when there is no torque going to it then locks when torque is applied. Thus I dump my clutch when going around a corner on the street and I don't release it until I have straightened out. Otherwise my inside tire would try to spin at the same speed as the outside tire (which is spinning faster) and the inside tire chirps. Spools however permanent lock both sides of the axle not allowing for the variation in speed even while coasting. In this analogy part-time transfer cases act as a spool (always locked when 4x4 is on) and do not allow for the variation of speed between the front and rear axles.
Full-time transfer cases such as the NV-241 select-trac and NV-249 quadra-trac 4wd tranfercases in the Cherokee and grand Cherokee use a viscous coupler that allows for the differentiation in speed. However anyone who as aggressively tried to wheel a quadratec system that hasn't added a locker or limited slip will tell you that you can quickly end up with a one wheel drive Jeep when you start lifting tires off the ground.
This is the same reason I opted for a detroit auto-locker in the rear axle of my Jeep rather than a spool. The detroit automatically unlocks when there is no torque going to it then locks when torque is applied. Thus I dump my clutch when going around a corner on the street and I don't release it until I have straightened out. Otherwise my inside tire would try to spin at the same speed as the outside tire (which is spinning faster) and the inside tire chirps. Spools however permanent lock both sides of the axle not allowing for the variation in speed even while coasting. In this analogy part-time transfer cases act as a spool (always locked when 4x4 is on) and do not allow for the variation of speed between the front and rear axles.
Last edited by Roughian98TJ; 04-29-2012 at 02:56 AM.
04-29-2012, 10:45 PM
#12
Senior Member
You're kinda on the right track. The wheels need to spin at slightly speeds when turning. Thus on a high traction surface (pavement) the part-time transfer case such as the one in the f-150 cannot very the speed of the wheels getting torque between the front and wheel axle. The fact that the wheels are traveling at the same speed is what causes the hopping and chirping.
Full-time transfer cases such as the NV-241 select-trac and NV-249 quadra-trac 4wd tranfercases in the Cherokee and grand Cherokee use a viscous coupler that allows for the differentiation in speed. However anyone who as aggressively tried to wheel a quadratec system that hasn't added a locker or limited slip will tell you that you can quickly end up with a one wheel drive Jeep when you start lifting tires off the ground.
This is the same reason I opted for a detroit auto-locker in the rear axle of my Jeep rather than a spool. The detroit automatically unlocks when there is no torque going to it then locks when torque is applied. Thus I dump my clutch when going around a corner on the street and I don't release it until I have straightened out. Otherwise my inside tire would try to spin at the same speed as the outside tire (which is spinning faster) and the inside tire chirps. Spools however permanent lock both sides of the axle not allowing for the variation in speed even while coasting. In this analogy part-time transfer cases act as a spool (always locked when 4x4 is on) and do not allow for the variation of speed between the front and rear axles.
Full-time transfer cases such as the NV-241 select-trac and NV-249 quadra-trac 4wd tranfercases in the Cherokee and grand Cherokee use a viscous coupler that allows for the differentiation in speed. However anyone who as aggressively tried to wheel a quadratec system that hasn't added a locker or limited slip will tell you that you can quickly end up with a one wheel drive Jeep when you start lifting tires off the ground.
This is the same reason I opted for a detroit auto-locker in the rear axle of my Jeep rather than a spool. The detroit automatically unlocks when there is no torque going to it then locks when torque is applied. Thus I dump my clutch when going around a corner on the street and I don't release it until I have straightened out. Otherwise my inside tire would try to spin at the same speed as the outside tire (which is spinning faster) and the inside tire chirps. Spools however permanent lock both sides of the axle not allowing for the variation in speed even while coasting. In this analogy part-time transfer cases act as a spool (always locked when 4x4 is on) and do not allow for the variation of speed between the front and rear axles.