New Holland tc35a

[balernbud]

4x4 front axle will engage but when it starts to pull hard seems to not work, do these have clutch packs that could be worn?

 

[jinman]

No, it has no clutch and will not slip if engaged. However, the front differential allows one wheel to stop turning if it has traction while the other is in the mud. If you step on the differential lock, you can force 3-wheel drive, but there is no way of locking 4wd. The front axle has no differential lock, only the rear axle has that.

 

[balernbud]

something must not be engaging then or broken and when there is very little pressure on the fronts tires they turn but if they get a lot of traction the back tires will slip and the fronts do nothing. It has me confused any help would be useful.

 

[Harry in Ky]

Check the driveline splines and couplers. Each coupler has a roll pin through it to keep it in place. If the front axle pivot joints become loose from wear, it's hard on the splines. If you have spline problems it will be on the front, as that is where most lateral movement occurs. Try engaging the 4wd,and jack one front wheel off the ground. Try to turn the wheel by hand, slamming it back and forth as hard as you can. If all is well, it will turn a few inches and stop, both directions. You will see the driveshaft turn a partial rotation or so until the backlash is taken out of the gears and splines, then it should stop and not turn unless the rear wheels follow. Do that with each front wheel in turn to help isolate the problem. Should be same result on both sides.