Yeah, Thanks Pete! I'll be checking out my center/carrier/steady bearing today. From what you're saying, I shouldn't find a lot of play in there. I take it that rubber is fairly stiff? BTW, I did some googling today, and found some good trouble shooting sites. One is Diagnosing Causes of Steering & Suspension Vibration. You can also try googling driveline vibration or driveline noise, and some really good links come up.

 

Yes, thank you for that tidbit of information Pete. I have noticed on my truck that when I let off the throttle that I get a small thump as the drive line catches up with the speed of the motor due to slowing down and I think that my thump is that carrier bearing moving up and down in it's seat since I have about 1/4 of an inch of play between the rubber and the frame. The carrier/idler bearing sems to be in good shape but this may mean that it is time to replace this little guy.

I will see what i can do to shim it for now but I will also be getting this replaced as soon as possible as I don't want this thing failing. I've been down this road before with a Toyota and it didn't work out well then either.

 

Another thing to check would be the bearings in the rear end. I had a Peterbilt truck with a similar problem. I changed the u joints and the carrier bearing and it didn't stop the rumbling. I checked the yoke on the rear end and it was loose. I pulled the gears out and found the bearings loose inside. I had new bearings installed and everything was quiet again.

 

Ewwww. good info! I don't think I would have thought of that one! Oh wait, I didn't

 

Its amazing how much the mesh pattern on the ring and pinion can change when torque is applied and bearings are worn. It can mimic other driveline problems, and when you change the pinion angle with a load in the bed it really enhances the problem.

 

True enough! Well I think with that great information you gave us we'll all be checking our play in the rear end.

 

Another update... Just finished crawling around under the truck, and found some issues! When I first crawled under there, I noticed one of the rear u-joint cups didn't look right. With the truck in neutral, I twisted and prodded (by hand) everything I could, and didn't get any play (other than compressing the rubber in the carrier bearing). I jacked up the truck and put the rear end on floor stands. With the truck in neutral, the rear wheels started to spin. Tires looked good, but I could see almost 1/8" of run-out (wobble) in the driveshaft at the rear! Just a guess, but I'll bet that may vibrate at highway speed! Everything else was running nice and smooth throughout the driveshaft. Strange thing is that the u-joint is just over 1 year old! I really expected to find some play in the u-joint, but maybe I needed to use pry bars and whatnot to see any play...

 

did you ever figure out where it's not centered at?

 

Pretty sure the rear u-joint is toast, but I'll be taking it in to driveline shop today or tomorrow. The u-joint is just over a year old, so I need to find out why it was so short-lived.

 

Well, got the truck back from the drive shaft shop today. Big shout out to Chris at Pat's Driveline in Red Deer. Anyway, like I figured, the rear u-joint was done. One of the cup's seal was damaged by a rock or something, and moisture destroyed the needle bearings in it. The reason I couldn't move it is that the u-joint had somehow wedged itself into the cup. The other problem is that Ford has this goofy harmonic balancer at the end of the shaft. The rubber bushing that holds it in place started to deteriorate, and this balancer was way out of wack! The shop cut the balancer off, rebalanced the shaft, put a new u-joint in, and I'm back in business! Chris at Pat's Driveline said that it's quite common for these harmonic balancers to go, and they don't worry about replacing it. He showed me the one he took of mine, and it looks like it's made of cast iron, and he somehow split it in half to remove it.

 

So if one might be so bold as to ask such a question, how much or about how much was the job?

 

25 bucks for the u-joint, add labor and the Gouging Stupid Tax, total came to 190. Not too bad.

 

I've been follwing tis thread for a couple of days and I ALSO had the "Washboard" vibe. Just started one day while at the lake. It was slight at first and then yesterday it was getting real bad. I was like the person else where in this thread... Just let it blow up then I'll fix it. Well had a 2.5 hour road trip coming up and that was not the right thing to do.

Things that I repaired or re-worked:
1. Followed Guz's Hub rebuild and rebuilt.
2. Replaced the driverside "Knuckle seal" and dust seal.
3. Greased the living heck out of every zerk
4. Re-clocked the "mid" yoak to be in phase
5. Checked all U-Joints... all fine.
6. Checked all bearings...really just the ones on the drive train.

I am a Jeep rock crawler at heart and I almost beat myself for forgetting the FIRST step in locating moving vibes...

Isolate! Jack the rear up took off the rear most half of the rear drive shaft... Put the truck in 4 HI and drove around the area. On street and dirt. Could NOT get the truck to vibe at all. The day before I could just hit a man hole cover and it would start. So I go back to the garage and get the 4.5 Metabo grinder out and cut the STUPID BALANCER off. Took all of 5 mins. Cleaned up the shaft put it back in with loctite and WA LA... no vibe. Really.... Why would Spicer do this on an OFF-ROAD vehicle. I wheel the truck in the mountains around Silverton Colorado when the Jeeps getting its face lift... I guess I knock the balancer off just a little bit but the weird thing is it didn't start until a week ago... I was in Ouray for Labor day and ran Imogene and Engineer and nothing was vibing. Anyway thought you guys would like to know this one. And yes... you could see the balancer wobbling. Didn't mess with the weights so it's still balanced. Got the truck up to about 90 mph on a remote road... NO VIBE!

Bryan

 

Nice. Good information.
Well I also have some drive line noise that is starting up and it may be the start of what you guys are talking about. Right now it's just a little noise though still annoying but I will prepare for the worse and have some money set asside so that I can get the drive line balanced, carrier replaced and bearing on the rear pumpkin replaced.

Thanks for all the information guys. This has been a very informative post.

 

I have learned a little secret from a good friend at a driveline shop in ABQ NM... If you DO NOT TOUCH THE WEIGHTS on your drive shaft then repairing or sleeving it is easy.

If you know how to weld(key word KNOW) then find a cold rolled tube of your desired wall thickness, making sure your O.D. of your OEM shaft is @ best one 100th smaller than your sleeve.

EX: Jeep XJ front drive shafts are 1.75" in O.D. 2" .120 wall HREW or DOM tubeing is 1.76" in I.D. I have made countless double cardin(?) rear drive shafts for friends that have streched their wheel base and need new rear shafts. The weights are there to balance AGAIST the yoaks NOT deformations in tubes. SO... If you have a rock ding or even a MINORly bent shaft just measure twice, cut once and weld your sleeve in. Just make shure of your penitration with your welds. In theory you could get a .500 wall tube, cut your shafts about an inch before the weights weld on your cut to length sleeve and have a bomb proof drive shaft... albeit heavy as hell but bomb proof none the same.

Bryan