TFaoro

It is evenly spaced and not sparatic. The faster you drive, the faster the noise. Brakes replaced last summer (About 12K on them) Ball joints replaced this summer (About 5K on them) It's really weird because this started out of the blue on black ice. I used 4 low to move trailers around during the summer, then the first nasty snowstorm while using 4wd and this started. There were not any abnormal loud pops like something broke and is now grinding apart. I plan to do some diagnosing tomorrow by switching the vacuum lines on the CAD. That way when I put it in 4wd the transfer case will be locked in and the diff will turn, but the CAD will be out. If it makes the noise I can eliminate the cad and look at either diff, driveline, or T case. If I have it in 2wd the transfer will be disengaged but the CAD will be engaged. If it makes the noise then it can not be the transfer case.

Oil looked beautiful gold when I pulled the CAD. There weren't any flakes that I could see.

All of the universals looked and felt tight. I wish someone else could hear it. It sounds like a set of small gears are stripping off when going fast.

During the summers I drag around an 8,500lb antique tractor on a 6,200lb tandem dual gooseneck trailer. I also move a decent amount of hay on the same trailer. Honestly I haven't towed much or very heavy with this setup yet. I got the injectors a couple months ago and the turbo towards the end of the summer. As for the old setup I din't ever tow with the tst on I always just set the smarty to 5,7, or 9. Set to stock you can't hardly get the egts over 1,000 deg. With the smarty on 9 I can get them up around 1200 deg, which isn't bad considering how steep the grades are and the elevation I'm at. 5,280 ft definitely takes its toll on the air supplied!

What RPMs was it happening at? Or was it through the whole RPM band?

It still sounds like it's coming from the front passenger side. Did some testing and man it hurts to hear it do it, but it seems like it does it most when there is pressure against the drivetrain (Shifting down for example) It clicks really fast just shifting down and going straight. It also does it when turning on pavement or slippery snow. The truck still does its hopping and "spins" the rear tires so it feels like everything is engaged, just some joint isn't happy.

I can't speak for him, but mine spools FAST. If you get on it hard 15+ psi by 1500rpm and 40+ by 1650. Works great for towing!

Ok replaced the actuator today... It was bad because it wouldn't hold vacuum on one side and the new one held it on both sides, but the popping noise has not gone away. My 4wd is working as it should - front and rear tires are pulling even when it does pop. Does anyone have any other thoughts? I'm thinking driver side U joint??

How long is a long time? How cold is it? What kind of oil do you run? These all factor into how fast the engine will build oil pressure.

I changed the little rubber boots and connectors on mine to clear gas line that we use on snowmobiles. It doesn't suck down and should last just as long as the rubber.

Good thought, but no. The fork could not have still been moving after trying to get it to hold vacuum that long

Thanks Ed! I am going to start with a tape measure, and if any of them seem "different" than the rest I will be giving you a call.

Mike I did it with my mouth.... on the side that pulls it into 4wd it wouldn't hold anything. The side that pulls it out of 4wd held a vacuum

I'll check that out Mike. It is confirmed it's the cad. I had my brother drive the truck while I listened and the popping is coming from the CAD area. Luckily it's not the transfer! I didn't think it was because I had it all torn apart this summer to re-seal it. Everything inside looked great!

Sorry guys got stuck at work on hold for an hour then had to stay another hour to figure out timecard problems. By then it was dark. Thursday is my next chance with some free time! My plan was to check the lift of each pushrod.

Will be doing that in a couple of hours

So hers was slipping inside the transfer case??

I had already put it back together last night I live at an apartment complex. I may do this when I get home. Oil looks perfect. I changed it along with both front seals this summer. I don't think the spiders can be toast because I can spin the driveshaft in 2wd and it spins free as can be. Not chunky or rough like I would suspect it to be with broken gears.

Thanks Mike. We'll get it figured out eventually!

Rancherman you have a PM

I pulled the bolts and took the fork/actuator assembly apart. Everything looks good. The collar slides easily back and forth, and the shift fork is not frozen in its own housing. Vacuum in the truck works great. Quickly changes between floor/deforst/face/face and floor. I even checked vacuum down at the actuator and it seems good. Rancherman the light appeared solidly on, but I have a gauge that sits right in the way of the light so I really have to look for it.

Mine does... Kinda wishing it didn't right now. Looks like the actuator is going to be 70+ bucks

I'm interested in pictures!

As far as I know all of the 24V cams are the same. The only difference is the gear, which has the tone ring for a sensor in 2001.

I went snowmobiling the other day and now have popping going on inside my front end when in 4wd and there is pressure on the drivetrain. I believe it is the CAD as I have already jacked up both sides, checked all 5 U joints and turned the driveshaft (Pinion feels tight and driveshaft turns with ease). All U joints look good and have no slop in them. The transfer case has very little slop as well. The only thing left is the CAD. I think the diaphragm inside the actuator has gone bad because I can suck on the side that pulls the CAD over onto the disconnected side and it holds the vacuum. If I suck on the other line, it does not hold vacuum. Is there anything else I'm missing?