I was playing around with the truck the other day and I got on it at about 60mph in 3rd gear and the truck started pulling and then suddenly the rear end started vibrating. It's never done it before. Then today I was playing around and I was at about 65mph in OD and when I get on it it would pull smoothly and then at about 75 or so it would start vibrating. Now, if I was to gradually accelerate up to speed there's no vibration. It's only when I get on it. It just started doing this earlier this week. I've got a 4.5" lift with tuff country ladder bars on the rear. Yall got any ideas?

 

u joint, slip yoke, pitched a d line weight, do you get any noise or just vibration

 

I agree...

Sounds like driveline problems..

Check both front and rear shafts and U joints. You might have to remove them from the truck to check them properly. Look for sloppy U-joints and the slip joint.

Then after all that check your tires... You might have thrown a weight.

 

Maybe the rearend is just afraid of all your new found HP and is shaking out of fear.

 

That's good! I'll remember that one!

 

If it's afraid of this then what's it gonna do when I build the tranny.

Geico, I've got disks in the rear so I don't think it's the brakes. Can you even adjust the disk brakes?

high country, no noise at all. Just a vibration at full throttle from 65mph and up. Even if I stand on it from a stop it doesn't do it at all. It's only at full throttle from 65mph and up.

Mopar1973man, I was kinda thinking u-joints but not to sure. I sure hope not. Those suckers ain't fun to change.

Keep em coming guys.

 

If you really having problems getting them to pop out... You can heat the yoke with a propane torch to relieve the tension of the yoke on the bearing cups. If it really bad you can use a acelene torch too... But don't get carried away heating it. While it's still warm the new one will just about drop in for you...

I've had to do this on my old 1972 dodge... The front shaft refused to let go of the U-joints... Just my 2 cents to the effort...

 

If it ends up being u-joints, I'm gonna take the thing to a shop and let them press them in and out. The only want $5-10 to press them in and out.

 

I forget that your BIG city kid... Us rednecks don't have shops around the corner... We got to travel maybe 60 miles to a diesel shop or such...

 

I have to travel about 20-30 minutes for a decent driveshaft shop. It is nice living in a city sometimes. I'd do it myself but I just don't feel like it. We did my buddies and ended up having to cut the old one out with a grinder and beat it out with a screwdriver and a hammer.

 

If your going to take it to a shop you might as well let a driveline shop look over both shafts and be sure there not bent and are balanced yet!Just my 2 cents on it...

 

True. Never thought about that.

 

For those of you that change your own. when putting the new ones in put a light film of grease on the cup and they will slide in easier. I know that it works. I use to put them in without and they were really tight going in.

I use a bench vice to press them in. Just be careful and dont drop a needle. Put one cup partually in the yoke till you can get the pieces mated and install the other cup and keep it from slipping completely out of the other cup.them make sure you go slow and straight.

 

Another thing to check is your pinion shims. They are between the lift block and the leaf spring. They have a tendency to crack and fall out. This will leave your axle u-bolts loose. If you find the u-bolts loose I would replace them.