I've still got a vibration in the driveline. It's worst when I have the front hubs locked (doesn't matter if it's in 4wd or not). It's definetely speed related because it gets worse above 45mph. But the weird part is it's not always really bad. Sometimes it feels like the truck is going to come apart above 45, and sometimes it smooths out. It has also started vibrating at idle when it's in drive, I shift into neutral or park and it goes away. When it's at its worst it sounds almost like an airplane propeller is under the truck. To date I have checked the tranny fluid (good), checked the transfer case fluid (good), checked both the front and rear differential fluid (good), rotated the front driveshaft through all possible combinations (rotated the end hooking up to the transfer case 180, then the differential 180...etc.), the rear driveshaft was rebuilt and balanced last year and the u-joints have been greased, the front driveshaft was rebuilt and balanced last month (both at a reputable shop). I need to do the front wheel bearings, but that wouldn't really explain the vibration at idle or reduced vibration with the hubs unlocked, and they aren't that bad. I'm at a complete loss as to what to do, and (gasp) I'm thinking of taking to a driveline shop to have it looked at.

 

Just a guess you ever check your motor mounts?

 

Not since I installed the new engine couple years ago. I torqued them on, and then retorqued them a couple hundred miles later. I'll add that to my list though, at this point I'm game to try just about anything. It just seems that it would be just as bad without the front locked, but I guess the extra strain could do it.

 

How about tranny and transfer case mounts. Are all of your U-joints in good shape?

 

Try your tourque converter. mush

 

It may sound trivial, but check the routing of your exhaust pipe and how close they are to any body, suspension or frame. I had a vibration that drove me nuts til I got underneath and found my left pipe about 10 inches from the manifold was about 1/8in from part of the underside of the body. It would vibrate at certain RPMs and sometimes at idle as well.

 

JdGreen-
I was wondering if it goes away when you press on the gas.

 

Yea it does...but it seems to come and go depending on what I am doing

 

Dang i have that same problem.

 

LOL Yea it is a pain...hehe kinda sounds like a giant vibrator! Maybe thats why I always have all those women chasing my truck.

 

Haha....NICE. So do you still ahve that problem or did you fix it. If you fixed it what all does it take to do it.

 

I lossened the bolts on the collector wherer the pipe joins the exhaust manifold....had my buddy push/twist the pipe a bit to give it more room. It fixed it but its only temporary...dont want to put any undue pressure on the manifolds and cause worse probs. I am going soon the get new exhaust and headers but thats only in two weeks. SHouldnt be a prob for that amount of time. Will be like this for about 6 weeks total
.

 

I'll try to answer all of your questions. The transfer case and tranny mounts are all tight. It couldn't be an exhaust problem, the whole truck vibrates. The u-joints are all new front and rear and are in good condition. I've tried to move the driveshafts and there is no play or looseness to indicate that maybe a bad u-joint was installed. The vibration does not go away when I let off of the gas, it isn't as harsh but it's still there. I'm almost starting to think transmission or torque converter. I noticed yesterday that the tranny didn't want to kick down a gear when I was slowing down. The vibration at idle also is kind of pointing me at the torque converter. I'm almost wondering if I'm having a problem with the tranny fluid in the torque converter. I'm no expert on transmissions and torque converters, but it seems to me if the torque converter is spinning and isn't full it might cause vibration.