Bad towing vibration!!!

[jnelson]

When bobtail truck has no vibartion. With trailer hooked up I get a bad vibration which seems to be originating from the rear. Had a buddy of mine pull my trailer last night with his dodge and the trailer pulled great.



I can load my trailer and the vibration goes away. Get unloaded and vibration comes back. Vibration is only from 61 to 76 mph.



Ive rotated and balanced tires on truck, checked u-joints, new carrier bearing, inspected suspension, put more air in airbgs- took air out of air bags, it doesnt matter.



Im going to get tires on rear rebalanced and inspect rims today. this vibration seemed to start out of the blue.



Im at wits end. Any suggestions? I run hot shot so this problem is something I been trying to fix for weeks. Its driving me crazy!!! :{

 

[Diesel Nut]

I bet its your center bearing in the driveshaft. When youhave the truck loaded it lines the driveline up in a straight line. When unloaded, the driveline is at an angle. This is where you get the vibration from. Try shimming your centerbearing a little at a time.

 

[GShail]

My truck has been giving me similar problems, but at different speeds. Occurs only with loaded trailer at low speeds in 1st & 2nd gears. Goes away after you get in 3rd. I also have tried all of the above things and allthough the symptoms lessened they have still not gone away completely. One thing that I ran into different than jnelson is that the spline for the carrier was bent on my truck. Replaced with new shaft and another carrier bearing and the problem is less noticable but definitely still there. I too have inspected my suspension and tried my air bags at different heights to no avail. Nothing seems to cure the poblem which crept up overnight. I have a sneaking suspicion that here is an issue with the springs in the rear being weak from all of the hard use. I got into the differentials and everything is golden in there. So when the differntials check out, center carrier bearing and driveline good, tires balanced, u-joints replaced, what is it? Proper shimming? I guess I need someone who really knows how to properly index the driveline as I have read in other posts.

 

[jnelson]

I bet its your center bearing in the driveshaft. When youhave the truck loaded it lines the driveline up in a straight line. When unloaded, the driveline is at an angle. This is where you get the vibration from. Try shimming your centerbearing a little at a time.

Why would this problem show up a 200,000+ miles. the vibration was there before and after the dealer replaced the carier bearing.



I did get my tires rebalanced today and they were 1. 5 oz, 2. 5 oz, 3. 5 oz, and 0 oz off from right to left. i'll hook up tomorrow and find out how she does. I'll be going to Midland PA on tuesday with my smaller trailer - so Ill get a break from the vibe.

 

[MACHINEST]

On a two pc drive shaft all the u-joints has to be timed,meaning in line as they go back,if the back drive shaft was pulled off the splines,make sure your u-joints are in line... .

 

[jnelson]

no vibration for 200,000. replaced carrier after vibrtio started still have vibe.

 

[CSnyder]

I run hotshot as well and had the exact same symptoms last year when towing empty but it would dissappear as soon as I was loaded. I tried all the truck driveline remedies with no cure so I took it to my local Cummins big truck shop and had them look at it with the trailer in tow. They found that I had a couple bad tires on my gooseneck that were out of round from either turning short on pavement loaded or from brake lockups. All my tires had excellent tread left but I took their advice and replaced the rear four tires on my tandem dually trailer and all my vibrations went bye bye. I hope this helps, Chris