4x4 issues!!

[marc chouinard]

I have this '02 Trac that when is put into 4H seems to give a binding sensation in the driveline...with a hard pull to the right and then it all lets go with a loud clunk...THEN when i go to disengage it from 4H, it takes forever to disengage and when it finally does, it feels like i just lost the entire driveline! Any ideas? Anyone else been thru this? BTW all fluids are topped up.

 

[Yardsale]

I'm going to go out on a limb here a guess that you are not driving on a slick surface that will allow the tires to spin.I'm going to go out on a limb here a guess that you are not driving on a slick surface that will allow the tires to spin.



In short (and imprecisely), since the transfer case is not differentiated (does not allow the front and rear output shafts to turn at different speeds) when the four wheel drive is activated the front and rear drive shafts are effectively connected. When turning, the front and rear wheels (and the left and right, too) follow different paths and these different paths are of different lengths. Since the wheels are rotating at the same speed, they must some must slip or the transfer case binds.



This is what you feel. The clunk, if you are lucky, is not permanent damage.



Only engage the four wheel drive under three conditions:

1) When on low friction surfaces (snow, loose dirt, mud, sand, etc)

2) When driving straight (so that the front and rear wheels are traveling the same distance), but only for short distances. This really isn’t recommended, but may be necessary for troubleshooting.

3) When all wheels are lifted and not on any surface (on a rack). Again, for troubleshooting.

 

[marc chouinard]

When I am driving, the 4x4 engaged and on icy snow covered roads, when i let up on the gas pedal and begin to slow down from 80k, you can feel it starting to bind up?? and then it lets out this loud clunk and that binding sensation is gone for the moment. It was so violent once that it turned off the light on the dash. ive been told that because i put new tires on the front and still have old worn tires on the rear that the tires are different sizes...does tire wear affect sync that much?:wacko:

 

[Yardsale]

Different size tires CAN cause this. It should be minimized on snow or ice, though. Did you notice this just after replacing the front tires?



Some math:



Assume that the rear tires are 30 inches in diameter and the front are 29.75 inches in diameter (a 1/8" difference in tread depth).



Circumference front = 2πr, 2x3.1415X15 = 94.25 inches

Circumference rear = 2πr, 2x3.1415X14.875 = 93.46 inches



So, the difference in circumference between the front an rear tires is 0.79 inches and they are traveling that difference each revolution. That's a bunch.



It is possible that there is a mechanical problem independent of the tires.