u-joint or the hanger bearing (or steady bearing, carrier bearing, whatever you want to call it!)

The hanger bearing should only have movement in the rubber, if their is any slop in the bearing replace it.

For the ujoints, they are easy enough to check. block the tires, put it in neutral and spin the shaft back and forth watching for slop in the caps.

 

U-joints caused it on my truck.

 

would there be any reason weight would cause this to change?


When its just me driving, its at its worse. Load up with some people and sometimes i cant get the thing to do it... when it does, its not as harsh.

wonder if my shocks are shot?

 

You are not alone here. My truck does the exact same thing. Under power, off power, coasting, whatever, it does it around 45 mph. Yes, a big wobbly rear tire is a great description. There is another thread about surging but I think that after reading what everyone been figuring that its not pertaining to me since auto guys are the most interested and not manuals. Its not a fast speed vibration so driveshaft and tranny are out. Its the slow speed of the tires. I thought my tires were out of round but thats not it either. I have no idea what the heck causes this and its good to know that others are feeling the same thing. I've just come to the conclusion after years of brainstorming that its just the ergonomics of the truck. My differential is fine, good shocks, good tires, good u-joints, and so is everything else. Drive line problems like a u-joint or carrier bearing give a harmonic high speed vibrations, not a slow wobble. Especially at 45 mph.

As for your clunking when shifting, have you checked your tail shaft bearing, carrier bearing, all u-joints, or differential bearing? Those things dont necessarily have to give any other sign but a little noise until they get real bad. I've had u-joints look like they're just about to fall apart and only made a little squeak upon take off. Getting under your truck and man handling those items can reveal wear or fatigue. A clinking sound is also usually associated to the driveshaft since its hollow. Let me know what you find or if you fix that wobble problem but I can almost say for sure that you wont.

 

do you have the "trailer special" with the beefier springs out back and the D80?

 

Block the front wheels jack up the rear of the truck and spin one of the tires and watch and see if there is any play in any of your u-joints. Repeat for the front.

 

i have 3 ujoints, 2 piece shaft and the carrier bearing in there.


Limited slip, with the overloads, sway bars.. the whole nine yards.

 

Like I said before, given that you have the long bed and I have the short bed, I dont know if our differential u-joint angles are the same but I could see that being a possible culprit. I was going to jack up the rear end and bring the back tires up to 45 mph or so and see whats happening. I know thats very dangerous but I'd take all the precautions first. Maybe I could see whats going on unless its to slight to notice.

 

im thinkin that its the U-joints, a worn u-joint will cause vibration exactly as you describe

 

No I dont have a worn u-joint. I had one go not to long ago and replaced them all. Also a bad u-joint will hum a fast harmonic vibration not a slow wobble. This is a strange feeling. Really it feels like the tires are out of round.

 

sounds like a u-joint to me they can do all sorts of things when they go out

 

Believe me guys when I say that I want you to be right but I have been experiencing this for a long long time. And I know how to check for bad u-joints too. Also I cant imagine a bad u-joint lasting years without some other tell tail sign beside a little rear end wobble and not explode given the heavy hauls I do.

 

have you had your drive shaft re-balanced??

Ive done one ujoint so far. all i had time to do the day we installed the 5" straight pipe on the truck.

Im going to try the other two... see what happens

I thought about taking the Dshaft out and running in 4wd up to speed and see what happens... but i havnt been under the truck to see if fluid will leak w/o the slip yoke in there.

My buddy has a car dolly i guess i could do the same....

 

My driveshaft is balanced and runs smooth as silk. And like I said before if the driveshaft was out of balance or even if there was a bad u-joint, the vibration would be fast paced. At 45 mph your driveshaft is spinning pretty darn fast which will not give you a wobbly feeling like your tires are out of round.

Yes if you pull out the rear driveshaft, the tranny yoke will puke lube but once when the driveshaft was off I rubberbanded a plastic baggy over the output shaft hole so I could move the truck. Not sure how long it would say on but maybe long enough for your test.

 

Shudder = center (carrier) bearing rubber worn out, or better yet, put a poly racing one in it. Rubber center brgs don't like CTD abuse.

 

I dont have a carrier bearing. Short bed.

 

where do you get a poly racing one?

 

We do driveshafts @ my shop, I get them from one of my suppliers, can't remember the name off the top of my head. Check around on the 'net, should find some. If not, lemme know. I don't wanna get in trouble for advertising or something.

 

I looked around and had no luck.


I did find out they had carrier/center bearings in the 1930s fords

 

I have an '04 in my shop giving me fits, think it's the rear shaft needing balanced, will see. i think the damper on the slipyoke is loose=wobbling=vibration.

 

If your slip yoke is bad it tends to vibrate upon acceleration or take off.

I checked a little too and found nothing. Apparently there is no polyurethane transmission mount made for these trucks. Just about every other vehicle made though.

Ditch Baby, did you say that you have traction bars?

 

I'll check tomorrow, I don't remember where I got it.

 

Got the one here 99% vibe free. Took the damper off the slipyoke, balanced it, good.

Here's the poly bearings.

Inland Empire Driveline Service, Inc. - Driveshafts, Pinion and Transmission Yokes, Center Support Bearings

 

I'm confused. What are you referring to as the "damper" on the slip yoke? The only thing I can think you mean is the balancing rings you see on some drive shafts. Usually Fords and GM's have these and I've heard they can slip out of place causing problems but I dont have one nor have I seen a Dodge with one.

 

BTW on my '95 with NV4500 I get a shudder if my spring clamps aren't tight. Axlewrap.

A poly mount wouldn't be too hard to make. About like this, made to fit the available bolt holes.

DIY4X: Catering to those who enjoy doing it themselves.

 

108,000 miles.

100% stock.

Stock, original shocks. A leveling kit is in the works with bilstein (sp?) on all corners.


Crappy tires could be it. Ive never heard of the tires that are on the truck now. They are pretty new. But i did have alot of runout on them when i balanced them. But the wobble didnt change location after i rotated/balanced them.

Im going to swap tires/wheels with my buddy to see if this goes away. When it gets bad like it did a few mornings ago, it gets old FAST.

 

108,000 miles on the original shocks??? Hmmm. Maybe thats the problem right there. When shocks get old they usually act like they're not doing anything for the first 1/2" of travel. That would allow the axle housing to rock and could be the reason why it does it less for you when you have some weight in the truck. With that said, I'm still going to try tightening my shocks up to see if it makes a difference but I just haven't got around to it yet. I was just kidding about the tires too. They'd have to look like eggs for them to be the culprit and your right, it doesn't matter if the fronts are on the rears with my truck either.

 

my next stab at this is going to be shocks.


I hooked up to my 3000 pound bumper pull trailer today for the 1st time with this truck.

Holy sweet baby Jesus... the truck ride HORRIBLE at the same speed i have this hop in.

The smaller trailers i had made it chill out, not today.

 

Just wondering if you've gotten any farther with this or found anything else out?

 

I have not.

I just sold off one of my trailers so new shocks for the back should be in order soon.

 

Got new shocks for the rear

Bilsiens 5100s.

they helped ALOT. but the hop is still there... not bad though. I have to be "looking" for it to notice its there. truck rides much better too.

 

WELL??? Did they do anything to stop what we were talking about?

 

For the most part. the hop is still there, but its minimal... well i should say bearable.

 

At least your in the right direction. I noticed today that the little hop was gone once I had a 500-600 lbs in the bed.

 

Damnit, it started again. Went for a cruise along the beach this morning after running and it started the hopping again. Not as worse as before, but just enough to be annoying.

I give up...

 

I'm right there with ya. I cant figure this out either. I also cant understand where only a few hundred pounds in the bed will stop it from happening. Maybe it really is just crappy tires???