wallypedal

Yep, my turn dangit. I've just got a rumble/vibe that never was there before. It happens when decelerating, sometimes all the way to zero mph. Sometimes not there at all. You can see the body move in time with it at 2-3 mph. It's not RPM related, I can throw it out of gear and let it idle down and it's still there. I've done preliminary u-joint shaking and seal inspection, but haven't dropped a shaft yet. The sound is almost like when the pac-brake is engaged at about 1800 rpm - I even thought that was what it was at first!

I just returned from a trip where I ran a fair amount (25 miles) of gravel & snowy roads in 4wd. Also, some of that road was pretty nasty washboard. I never cowboyed my way through it, but the vibes were still nasty. Used low range through some boulders. The problem started right at the end of that trip.

I hope that's enough info for the experienced here to tell me where to look first. The truck has 30k on it w/original tires - Michelins.

I've messed with carrier bearings before, and it seems the rubber mount on these is a little too cushy compared with some of the others out there.

How does a driveway mechanic check for bad ball joints? How do you look for driveline inbalance? If you got it up on good jackstands instead of chunks of firewood, can you run up the drivetrain to 60-70 mph and see it happening?

I've searched here and chased about every related thread, but still need some help just analyzing my problem.
Thanks for the forum - please help the old guy out!

Newbie, profile not showing yet: 2004.5 2500 CTD LWB 4x4 6 spd qcab, 3.73's, pacbrake

roadrat

Well old guy i just went through that same thing, shudder real bad when comming to a stop, o.k. as long as there was torque on it but when decelerating it was real bad especially when comming to a stop, thought the truck was comming apart. It was the rear joint on the rear driveshaft, a few weeks after it was changed the joint on the front of the rear driveshaft went, same symptoms as the first one. I gave it the driveway check and could not see any sign of worn joints, even tried prying them with a bar and no movement, but they were the problem. If you are still under the bumper to bumper warranty, no charge, if your over but still within the powertrain warranty you have to pay the first $100.00 per visit so if you take it in under these conditions make sure they fix everything, you only pay the $100.00 once. Hope this helps.

rob ( also an old guy)

strokethis600

i had the same problem a few months ago, it was the rear u-joint on the driveshaft

wallypedal

I pulled into the garage where it barely fits through the door. Ran it up on a couple 2x8's under the left tires for a little more clearance. Stuck it in 4 low to ease up on the boards. Found the 'rubbing wire by compressor' from another recent thread and taped wire loom to it.

Then I poked and inspected and cleaned and push/pulled on every u-joint. I inspected the drive line angles too. Made sure the ball joint boots were good. Ready to raise the fronts free of the ground to check ball joint slop, and went to walk around the back of the truck. Lying on the driveway is a piece of mud about 3/8" thick, maybe 5 inches square, and curved and smooth on the inside like it had just come off a driveline!! Not shaped like anything on the inside of a wheel. It almost had to come off the rear DL. How it built up, then only part of it coming off I'll never know. I'm not even sure whereabouts it was stuck on.

What I do know is I drove the truck and the problem is gone. Oh yeah, and I'm a walking encyclopedia on drivetrain vibes now.... BTW, the rear DL u's showed a hint of grease and maybe movement at the edge of the seals, but I couldn't force any movement in them. I'll be watching.

Thanks for the replies!

N.Johnson

BTW, the rear DL u's showed a hint of grease and maybe movement at the edge of the seals, but I couldn't force any movement in them. I'll be watching.

Thanks for the replies![/QUOTE]


That's exactly what I see on my rig and it's a little older than yours. According to the shop manual DC says that's expected ,but I wished they had grease nipples on the joints. If you really want to be nosy have a feeler guage in your hand along with the pry bar when checking for movement on the U's. Have you noticed the rubber dust boot surface cracking on the drive shaft seal coming out of the tranny?

wallypedal

No, N.Johnson, I really hadn't looked that seal over yet, but I'm not surprised! I'll look now for sure.

one8upcb

I'm having a squeeking problem in that area, so i crawled underneathe the truck. While i was under there i was looking at the rubber seal where it comes out of the tranny. seems like its off 1/4 inch from where the rubber seal was at. Does that sound like it could be my u joints.