BAD vibration while towing

[atyates]

so my truck, details in my sig, has a bad vibration at highway speeds between 70-75 mph while towing. wont go faster than that with a trailer. only while towing. it doesn't do it without a trailer. I just put all new bilstein hd shocks on it, checked, checked, and double checked to make sure the tires are balanced and the truck is aligned. and it is not the trailer. I pull the same trailer with my wifes suv and my other truck and the vibration isn't there. any ideas? thanks.

 

[95Suburban]

Check u joints. Also, if the rear end is sagging from the tongue weight, it might be enough to throw the driveline angles off to cause the vibration.

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[atyates]

Check u joints. Also, if the rear end is sagging from the tongue weight, it might be enough to throw the driveline angles off to cause the vibration.

Sent from my 831C using Tapatalk

I guess it could be the u joints. but weight shouldn't be a problem. its only a 6 foot, single axle trailer with a 4 wheeler on it.

 

[95Suburban]

I ran with worst case scenario. You didn't mention what truck, or how much trailer. But I've had similar trailers make my old 99 suburban sag big time.
As for the ujoints, if they're marginal, then under load they can make themselves known. Another thing could be bearings in the rear axle starting to go bad. Again something you wouldn't notice until it's under load.

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[poncho62]

I am thinking "U" joints also........

BTW....you do realize that most trailer tires are only rated for 65 max...just sayin'

 

[atyates]

I am thinking "U" joints also........

BTW....you do realize that most trailer tires are only rated for 65 max...just sayin'

yeah I have no where near that much air in my trailer tires. and like I said, the trailer pulls fine with my other truck

 

[1997chevydriver]

yeah I have no where near that much air in my trailer tires. and like I said, the trailer pulls fine with my other truck

He's talking mph not psi

 

[atyates]

He's talking mph not psi

oh. I see that now. well it still wouldn't make since of why it doesn't do it under the same conditions on my other truck

 

[1997chevydriver]

oh. I see that now. well it still wouldn't make since of why it doesn't do it under the same conditions on my other truck

Correct. Just an extra tid bit of info

 

[94_C/1500]

I'd check u joints, could also be transmission or engine mounts. Could it be possible your hitch isn't bolted down toght? Possible not enough bolts? Could the receiver be wore? Maybe the receiver insert is wore?
I've seen a GMT800 hitch's receiver actually be wore out to where the insert would rattle around when towing.