I have had my 97 4x4 for about 6 months and used the 4x4 today in the snow and had a problem with it. First it wouldnt shift on the fly into 4 hi ( was going about 40, foot off the gas) and it just grinded. so i pulled over and put it into 4 hi. Got back on the road and the truck felt fine up to about 30mph and then the wheel took control of it self almost and started throwing me every which way and almost off the road. I am not sure what is going on with it. I put it back into 2wd until i got to the point of having to have 4wd and i put it in again and the truck seemed fine and i drove home at about 45 with no pulls from the steering wheel at all. I am not sure what is going on with this thing, is the cad fork not engaging right? I dont know a whole lot about this truck since i recently bought it but i would love to see if anyone can help me out in solving this. Every point i put the truck in 4wd there was snow and ice on the ground so i know it cant be because i didnt have enough slippage if that makes sense.

 

I'm pretty sure out trucks aren't shift on the fly like the 2007 I had, but I could be wrong.

 

The 231d transfer case is shift on the fly (in gear/foot off the gas-shift) but only into and out of 4hi. 4lo needs the transmission to be in neutral with the truck rolling 1-3mph.

Andrew, are you positive that your tires weren't finding a little bit of pavement through the snow and ice when you were getting jerked side to side? The truck would react like that if it found a little bit of grip with just one wheel at a time going down the road doing 30mph.
Then again, if the transfer case were in 4x4 and the driver axle was connected to the transfer case but the passenger axle wasn't then I could see it pulling you every whichaway.
Now I'm thinking that it didn't shift into 4x4 completely and the shift collar wasn't pushed all the way onto the passenger axle.
Check your vacuum lines that go to the CAD unit for cracks or being loose.
Next time give the shifter a really firm jerk to get it in 4x4 and see if it happens again.

The manual says that you can shift into 4hi at any speed up to 55mph but I have never put mine in 4x4 over 30mph so I don't know about the grinding. I would assume that with the two halves of the axle spinning faster and all that you just need to shift with authority (firm and fast). I only get a grind out of mine if I try to shift into 4lo without shutting the engine off.

 

Shutting the engine off? Wow, I never had to do that. For mine to go into 4lo, I usually need to put it into reverse first, and then into nuetral. If I try to go from drive to nuetral, and then into 4lo on the transfer case, it usually grinds.

 

Never tried that. I tried a 4lo shift twice after I got the truck and it let out a horrible grind both times so ever since I just put the transmission in neutral, shut off the engine, shift into 4lo, start it up and go.

 

Check the snap ring in the rear of the transfer case too......

 

If the t-case is engaged but the cad is not then no power is transfered to the drivers wheel. All the torque will go to the disengaged mid shaft unless there is a locker or a spool.

 

I thought it might have to do with the CAD. I will check out the lines and the unit itself and see if things are working properly. I was guessing that the cad just didnt engage the fork all the way the first time I put it in 4hi. Thanks for the info guys and i will let you guys know what I find tomorrow. And I was also wondering how to tell what the front end gears are. I know that the rear was changed to 4:56 but I read some where that the front has to match the rear for the 4x4 to properly work so I just want to check the front gears and make sure they match if that matters.

 

i don't think the cad is your problem. the cad either engages or it doesn't. there is no in between. like gerehead said, if the cad doesn't engage, then all drive train rotation evaporates through the spider gears to the intermediate shaft, and does nothing.

you have some drive line binding due to diferent size tires or gears, or dry pavement or bad drive shaft ujoints or something.

 

Ok so I am a little confused since this is my first 4x4 i dont understand them totally yet but are you saying there is something binding and it stops my cad from engaging at times or there its nothing to do with the cad fork system at all. I have always heard that our trucks dont drive on pavement in 4wd but even if i did find some non ice/snow pavement the ground was still wet i just dont get how i can be thrown from one lane to another like i was and it just be dry pavement hooking up. So as far as binding goes, could it be wrong size gears in the front? The drive shaft u joints are alright so i am thinking it must be in the gears? Is it possible for the fork not to all the way engage?