04 Sport Trac 4WD problems

[nyjet29]

I've been reading threads on serious explorations but this is the first time I've actually started a thread. I searched the site and was unable to find anything that helped with the problem ive been having.

WHen driving in 2wd everything works fine, but when i go into 4wd it will make a loud pop sound from the back of the car every 10 seconds or so. This is regardless of driving on street, grass, mud or anything else.

Any ideas on what might be the problem would be greatly appreciated. Thanks.

 

[600remguy]

First off, do you realize that our transfer cases do NOT differentiate between the front and rear drive shafts? Avoid 4 wheel drive on any hard surface. Secondly, does this occur under all conditions, ie driving straight, cornering, forward and reverse, or all of the above? Is yours modified at all?

 

[ncranchero]

Possibility of a couple different causes, IMO.

Sounds to me like maybe the tire diameter is not matching front-to-rear. Maybe new tires on one end and worn tires on the other?

Remove the drive shaft and examine the u-joints and grease the slip yoke. Engaging 4x4 will put more stress on the u-joints and may expose a bad one when using 4x2 wouldn't. (see below)

Also, in all cases I know of there is a .01 difference (i.e. 4.10/4.11) in the front and rear gear ratios to make the front "pull" ever-so-slightly more than the rear "pushes" when 4x4 is engaged. (You'd only see this if looking at the stampings on the ring gear.)

Engaging 4x4 on non-slick surfaces not recommended.

 

[nyjet29]

its not modified at all. The only thing i've really done is gotten 4 new tires. I'm gonna take a look at it later on and will reply with whats up. appreciate the responses.