Archived 4x4 not engaging

[WBodine]

Need help as we are experiencing snow, ice, rain and mud... non typical west Texas problems. I can either shift it in 4 low or 4 high and the truck feels to gear down, but the front axel is not engaging. Need HELP!!!

 

[klaybus]

Vacuum leak on the CAD system... . Look at the vacuum lines that connect at the front differential & on top of the transfer case.



Clay

 

[robertyoke]

on my 98 truck the 4x4 quit working. the vacuum part was fine but the pin that pulls the collar to lock the shafts together had broken. had to buy the whole vacuum assembly.

-robert

 

[McLaughlin]

My daughter has had the same problem with her 96. Every time we have found a bad connection at the front axle where the vacuum lines attach. So far we have been lucky and only had to pull the connector off clean it up and put it back on and the 4x4 has worked. It appears the rubber connector doesn't fit tight anymore and sometimes causes a leak which prevents the front axle from engaging.

 

[JAmos]

My problems have been the switch on the transfercase sticking and not sending the vacuum to the front axle to engage it. I believe that the switch sends vacuum in one line to keep it in 2wd, and sends vacuum in the other line to engage the front axle a few seconds after the transfercase has been shifted. This attempts to bring both halfs of the axle shaft to the same speed to allow for a smooth engagement. Find a spot to reverse the two vacuum lines(what was the easiest on my 95 was switching the lines where the steel lines that run along the frame connect to the plastic lines coming from the switch on the t-case). If this causes the front to engage then its the switch on the t-case that is bad.



Jordan

 

[WBodine]

Well I found my problem. Where the vacuum harness hooks to the switch on the transfer case it had got wet with diesel because of recent fuel problems, and swollen up and got spongy. A zip tie was the quick fix pulled tight holding the rubber to the switch. I will order a new vacuum socket plug... Thanks for the help... ... . Oo.