2001 Sport Trac 4x4 Problem

[FollowTheSapper!]

New here and have a question regarding the 4x4 system...4x4 engages in/out of both ranges fine, however within a minute or so of being engaged in either range, the 4x4 disengages with a hard "thud". Feels like i hit a pothole. I was told by the dealer that the difference in wheel diameter will do it. There is noticable difference in tread wear between the front & rear. Any other ideas or is this most likely the culprit? Thanks for your time.

 

[600remguy]

Just an FYI, but the Trac's transfer case has no differential propertys. The front and rear driveshafts turn at the same rate/rpm and the tires must slip to relieve pressure on the driveline. Only engage the 4x4 is conditions which allow this.

 

[FollowTheSapper!]

Thanks brother. I only ever attempted to engage the 4x4 during the winter when there is usually snow/ice on the roads. Actually, i found a stretch of road with over a foot of snow, engaged the 4x4, and it still happened.

 

[a351fan]

yes a diameter change from front to rear will make a differance, the front tires will turn at a faster/slower rate then the rear and that could cause your problem. Not to be too preachy but, it is important to buy all 4 tires at the same time and have a regular tire rotation schedule so they wear at the same rate.

 

[FollowTheSapper!]

thanks a351fan. I have only owned this thing for approx. 6 months and the front tires were slightly new than the rear, but of course i was unaware when i bought it that the 4x4 system was so touchy. i plan to get new tires/rims soon. Just hope that is all that is wrong. Thanks again.

 

[Gazapo]

My 2001 made a loud clunk like that recently when coming out of 4 low, after I had only gone a few feet in foward and reverse on my side lawn. I was planning to change the transfer case fluid soon because I don't know the last last time it was changed, if ever.