Truck is a 98 4X4 1500 w/ the 5.2 and a manual tranny. Don't know the t-case model, and I'm sitting at work so I can't go out and check.

Alright guys and gals, here's the issue. Many of you may remember I was trying to search down a 4X4 problem a while ago. I spent a lot of time trying to narrow things down and the CAD really seemed to be the problem, but it was always intermittent when I was testing. During the testing, I also played a bit w/ the driveshafts and such to see if it was the t-case. I heard noises, but a friend of mine told me they were normal. I went ahead and installed a Posi-lok because I just couldn't figure if it was really the issue or not.

When I installed the posi-lok, I also went ahead and replaced both front axle u-joints as I found they were shot. I thought that the popping must have been those u-joints.

So I get all reved up to go play in the mud after a couple days of good rain and guess what?...You're right! No 4WD. Here's the more narrowed down things since I now have more control w/ the posi-lok:

1)4-hi and 4-lo make no difference, same issue
2)No noise at all in 2-hi
3)When testing the driveshaft previously (pre-posi-lok) there was a ratcheting sound in the t-case. This is the sound my friend told me was normal. Sound only comes when I spin the front shaft, rear is just fine.
4)posi-lok engaged, t-case engaged, driving --> Loud BANGS every now and then (what I thought was possibly u-joints), and a grinding/whirring sound (inside the cab diagnosis seems to be coming from t-case), and vibration on the t-case lever
5)posi-lok engaged, t-case disengaged, driving --> No sounds, but also obviously no 4X4.
6)posi-lok disengaged, t-case engaged, driving --> Couldn't get it to make any of the loud bangs, but the grinding/whirring sound still there whenever I'm moving and it does increase/decrease w/ speed.

Searching provided a lot of people asking if there t-case was gone and finding out it was the stupid CAD by the end. I did find one post from the Dakota forum about loose chains and one of the guys finding out that was the problem. However, he still had 4WD.

Long post, I know..but HELP!!! I've dumped a lot of $$ into the truck fixing all these "little" problems.

 

I'm having issues with my T-Case and/or CAD too. Mine makes a grinding sound, like when someone shifts and grinds the gears. I have a 98 sport 4X4 with the 5.9 and an auto trans. Mine does this in 4WD and 2WD. 2WD does it more when driving straight and accelerating, and in 4WD it "seems" to only do it when your turning.

Sorry for jacking your thread bro. But it sounds like we may be having the same problems.

 

Is the fluid clean and topped off? Anyway, it sounds to me like your front drive gears in the t-case are toast but, I believe there's an adjustment that can be made to the linkage and if it's not adjusted properly, it may not be fully engaging the gears and you're getting the grinding from half engaged teeth. Two extremes on repair work.

 

Ouch. Not what I wanted to hear, but also kind of what I suspected as well. So I'm guessing either way I'm looking at a rebuild? Is this something I could do on my own? Mechanical knowledge is above average, but I'd definitely not consider myself a pro.

I guess this means I'm not going to be putting 4.10s in this summer.

 

I'd take your rear shaft outand check your rearoutput shaft for play. There's a snap ring that holds the back innards in place and it is prone to breaking under hard usage. Just a thought.

 

I can't say that's exactly what it is but it seems like that'd be it. Someone else might have rebuilt one before and could give you more info on it and the rest. I've heard they are a lot easier than you'd think but still, I think it's a pretty decent undertaking. I don't know if you need any special tools for it and that's what I typically run into. (Half apart and need a special tool with no way to get it.)
I suppose if that snap ring broke it would cause a misalignment issue. Either way, that's still getting inside. Hopefully it's just a linkage adjustment issue. The bad thing is that tranny shops have such a bad reputation that it's scary to take it to any of them. It almost seems like every time you go you need to rebuild a transmission for some reason.