I have a 98 F150 4x4

When I shift into 4 High, and for a minute or so after I switch out, there is a Clicking coming from my front end. Does anyone know what is cusing this?

 

When you unlock your transfer do you back up kinda quick before you go forward? sometimes the the transfer will not release and it takes a minute to when you go forward.

 

You might be hearing the vacuum motor engaging or disengaging the front axles. I might be normal. The vacuum motor is mounted just to the right of the front diff on top of the axle tube. You'll see a vacuum line going down to it. Hope this helps.

 

The thing is though, the clicking is constant when it is engaged, when not engaged it eventually stops.

 

Sounds to me like a CV half shaft is going out. If it is a CV then you will get more noise with power to the fronts due to the increased tourque on the shaft. You will get some noise when the fronts aren't engaged because they are locked in the hub and are moving with it. I just replaced one of mine for $130 with a lifetime warranty on it. There fairly easy to replace, at least it was for me.

 

Another thing I just thought of is it could be your U-joints on your front drive shaft. Sometimes your four wheel takes a moment to disengage so the drive shaft would still be spinning during that time keeping torque on your universal joints. Then the four wheel disengages and you drive shaft doesn't receive any more torque from you transfer case causing the noise to stop.

 

so is it at bad thing to drive when it is in 4x4 and is clicking. or is it just the way it is, and its ok.

 

First of all, it should not click when in 4x4. Second of all, you absolutely do NOT have to back up a 97-03 when disengaging the 4wd. If you need to do so in order to get something to release, there's something wrong with the system. Third, it won't be a halfshaft. If it was a halfshaft, it would do it all the time as the halfshafts are turning all the time. It would get louder when cornering as the joint angles increase as well.

Finally, I think I would have to agree that it's probably a bad u-joint on the front driveshaft. The symptoms fit. When you engage the 4wd, the front d/s spools up to match the rear d/s speed, and the squeaking starts. When you disengage the 4wd, the t-case unlocks the front shaft, but the front drivetrain can continue to spin for a little bit even after the center-axle disconnect breaks the passenger side axle shaft. (The disconnect takes a few seconds or more, and momentum will keep it spinning for a little bit).

I'd be looking at doing the front u-joints, and if the fronts need it, the rears can't be far behind.

-Joe