SUV Owner Problem:

My 1993 Ford Explorer SUV works fine when I am driving in 2 wheel drive but as soon as I put the SUV on 4X4, it pulls to the right. This happens whether I am cruising or applying the brakes. I have tried rotating the tires and it did not make any difference. Before doing that, I also checked the outside diameter of the tires and they don’t appear to be mismatched. I want to take it to an alignment shop hoping that maybe this truck has a suspension problem like McPherson struts or stabilizer bars. But before I do that, can you advise me as to what I am missing here?

SUV Tire Advisor:

The 1993 Ford Explorer SUV uses either a manual or automatic locking hubs to engage the 4WD. As soon as you apply the locking hubs, the front axles will go into 4WD mode. When it does engaged, both u-joints of the front drive shafts will be loaded to transfer the twisting power of the shafts. When it is on 2WD mode, the front shafts basically freewheels which does not put stress on the u-joints.

If the pulling is happening only on the right side, I would look at the right side u-joint and check it for the following problems:

Does it flex when you pry it? It must be free to move when pried to compensate for all the different flexing of the shafts. If stuck, replace them as a pair on both sides.

Are the u-joints lubricated? Grease fittings must be greased to lubricate internal roller bearings. Again you do this to increase flexibility of movements of the shafts. If there is a doubt the grease fittings are not taking grease, replace both u-joints.

Replacing the u-joints should fix this pulling problem of the SUV but if not, I would consider taking the right side drive shafts and inspect it for defective or seized splines.

Notes:

When in doubt, bring your car to an authorized Ford dealer shop to make sure your tire problem is fixed.