i was driving my 98 4wd 1500 the other day just cruising around town and the i heard a grinding sound but only for2 seconds and it kept doin it but randomly i dont think its anything with the tranny cause it still shifts fine and doesnt stutter or stall or anything...i took out the front diff acuator( i think thats what it is) and it seemed to be fine...it sounds like it comes from the transfer case or somewhere up front...it almost sounds like the 4wd is trying to engage...it does it in 4wd also...im stumped...and i need your help!!

 

a common problem is a broken snap ring in the t-case rear output shaft. it allows everything to shift and hit the case. do a search here for a more info. its an easy fix.

if your vacuum line is not like it should be, the CAD collar might be flopping back and forth. you can test for vac at the cad. should have vac on one line in 2wd and vac on the other in 4wd.

 

how would i check the vac? before i took the cad off i unhooked the vac lines and it still did it...could it be the transfer case switch?

 

label your vac lines at the cad, so you know which goes where.
start engine, in park, e-brake on.. shift t-case to 2wd.
disconnect one line at a time from the cad. feel for vac. should be pretty strong.
add 2wd note to the label with vac on it.

shift t-case to 4wd. test lines for vac.
add 4wd note to that label.

if all your doing is testing for vac, you can stop now.
if you want to test your cad, then jack up the front and do a couple more tests.

engine still running, shift trans to neutral....
while in 4wd, spin the passenger side tire. front axle should lock up at the cad and front drive shaft should turn.
shift t-case to 2wd, spin passenger side tire. front axle should be unlocked, and front drive shaft should not spin.

this tests for vac and proper cad operation. if you get any grinding, investigate further.

do a search on t-case output snap ring for more info on that problem

 

ok i jacked up the front and figured out which line went to what and it seemed like it was working...but i tested the cad and in 2wd i spin te pass side tire and the front shaft doesnt spin but i put it in 4wd and spin the pass side tire the other tire spins as well but the front shaft doesnt spin....is that because the rear isnt jack up? or is sumthin wrong or am i just an idiot? haha

 

your drivers side spins backwards - OH NO.. your front end is assembled backwards. no, just kidding.

when in 4wd, and you spin the passenger side - any spin of the drivers side, in either direction, and/or the front drive shaft, is all normal. this indicate that your CAD is locking the axle halves together properly.

so - if no grinding coming from the front end during that exercise, it doesn't sound like its the CAD doing any kind of out-of-control locking or unlocking.

see if you can pick up on where its coming from. t-case output shaft is common,