4x4 problem

[BD72]

I have a 02 Sport Trac with 61,000 on it. Yesterday, I noticed a clunk sound when it was in 4x4. In 2 wheel drive, there is no clunk. Is this a bad U joint?

Thanks!

 

[ncranchero]

Was that just when you engaged 4x4? Was it engaging 4x4 Hi or 4x4 Lo? You WILL get a slight clung when it goes into Lo. Was the clunk when you were moving.....fast slow? Need a bit more info.

 

[BD72]

Thanks for your reply! I get a chunk sound after it has been engaged in 4x4. The sound is every so often when I am driving. It doesnt matter if I am speeding up or slowing down. It is just a chunk when I am moving like I am driving over something in the road. Maybe a bad CV joint?

 

[ncranchero]

U-joints would be my first suspect. You may have to drop the driveshaft to check them though.

There are things you may or may not be aware of. If you are then disregard this paragraph but since you're fresh here I have no idea of your 4x4 knowledge. You're in TN & I'm in NC so our weather is not too different. Your comment about "driving" in 4wd raises questions since we've been nowhere near freezing so icy conditions are out. You're Trac is 4wd not AWD and is not intended to be driven engaged on hard dry surfaces. Tires, mismatched size/wear will make the 4wd do bad things.

Hope this helps a bit.

 

[BD72]

I have tried to check it with the driveshaft still in and it seems to to be okay. But, I will have to drop it to check it for sure. Heck it could be both

 

[BD72]

BTW Thanks for your help!! How can I tell if the CV joint is bad?

 

[ncranchero]

They usually raise such a racket you know they're bad. Grip the axle part with Channel lock pliers and move it back & forth, similar what you would to the drive shaft. The U-joints have many needle bearings and it's more difficult to check them by hand (unless they're destroyed) but the CV's are just 3 (usually) ball/socket bearings and much easier to check.

 

[BD72]

Thanks! I will try it. I only thought it might be both because it seems the steering pulls to one side in 4x4 now. I was actually out at the job site the other day when it happened. I have never had any problems before. We love our Trac. We hope they keep making them!

 

[ncranchero]

You may be right then, about the cv's.