1997 2500 cummins. I tried to put my truck in 4 wheel, but it acts as if you tried to change gears in a manuel trans without pushing the clutch in. (grinding noise) i can not get it to engage. I'm not familiar with the air actuator system on this truck, or if thats causing it. anyone have this problem or familiar with the system.

 

When mine would not engage, it was a vacuum issue. But would shift fine so I don't believe that will be the issue. Transfer case fluid ok?

 

The vacuum system is just to engage the front diff, doesn't affect transfer case shifting.
When does it grind? Trying to shift it while moving or sitting still?

 

It does it while sittin still.I havent really ckecked anything out yet, i just bought it from a buddy last year, he said there was something wrong with the 4wd but he didnt know. I just havent had any free time until now.

 

Chris that truck looks really familiar!!! I think it used to be parked next to mine almost everyday!!! haha how are you liking Arizona? Thanks for the tip, i'll check it out

 

Is it an auto or standard? It's funny it would clash sitting still nothing should be turning.....

 

Its an automatic!

 

Are you referring to going into 4hi, or 4low? If 4 low, you need to shift quick- you go past neutral, and unless the truck isn't running, the gears will start turning when the transfer case goes into neutral (if the transmission is in gear or neutral- shouldn't do it in park). If it is doing it going from 2hi to 4hi, and you are sitting still, then you have a problem inside the transfer case, it sounds like. The front CAD would have nothing to do with your described problem.

 

Agreed!!

 

ok gentlemen, I appritiate the hlp, I actually had some time to check out the system today on a lift. I got it to shift into 4 hi, 4 low... it shifted through everything just fine and the front drive shaft was turning. ...but the front tires were not engaged!!! my vents for hot an cold were stuck on defrost and wouldnt change, so i checked out the vacuum lines and BINGO!!! disconnected! hooked it back up, now I have control of my vents oh and now I have 4wd!!!