vibration

[melmount]

shocks have 1k on them.
What about ebrake getting all screwed up in the hub? The e brake does not work?
I may pull the axels and look.

 

[JLDickmon]

It clunks every time i come to a stop or reverse to drive etc. Any thoughts?

that's the slip yoke binding.
pull it apart and smear a handful of Lubri-Plate in there

 

[BIG JOE]

shocks have 1k on them.

**

What about ebrake getting all screwed up in the hub? The e brake does not work?

** Could be ? If you have loose e-brake parts move'n 'round @ certain (38 mph) speeds.

I may pull the axels and look.

Let us know what you find.. I'd greaze that slip yoke too.

Joe

 

[melmount]

I used marine grease on the slip yoke yesterday, had it apart 10 times this month. Lubed every time. I think the clunk is ring and pinuion but would have to use a dial indicator on the stuff to know for sure.

 

[DaveBen]

Drive shafts are designed to go on the truck (or car) ONE WAY. It does not matter if you had it balanced, it should go back on the same way that it came off. There are two ways that the drive shaft can go on and you have a vibration, so you need to turn it 180° and re install it. Do not take the drive shaft apart.

Dave

 

[JLDickmon]

Dave is essentially correct, but I don't think that's where the problem is.
You'd have to have an absolute buttload of backlash in the ring & pinion for that to be causing a problem at that speed..

Same for the driveshaft. An improperly balanced shaft will cause a vibration, but it will be at higher speeds, and won't oscillate the rear suspension as you report.

I'm thinking you have an out of round rim, which is typical on duallie wheels, FORD duallie wheels in particular.

Think of Clint's issue.. he's trying to space out a wheel to keep it from hitting on his springs, and he's got to be careful he doesn't get too carried away with the backset or he's going to tear up wheel/axle bearings.

Same issue on a dual rear wheel. The center of force is not aligned with the center of load, and you can twist one pretty easily.

 

[JLDickmon]

I used marine grease on the slip yoke yesterday, had it apart 10 times this month. Lubed every time. I think the clunk is ring and pinuion but would have to use a dial indicator on the stuff to know for sure.

I'm a firm believer in Lubri-Plate, and nothing else; I'll let you know about the marine grease, as that's all I had on hand when I did mine today.

(However, I do have to run to NAPA and exchange two joints in the morning, and I'll pick up a tube for just such an emergency while I'm there)

 

[JLDickmon]

shocks have 1k on them.
What about ebrake getting all screwed up in the hub? The e brake does not work?
I may pull the axels and look.

go ahead, but e-brake parts floating around are gonna give you problems long before that speed (like 3-5 mph)

 

[melmount]

its a dually rear end dana 80. Right now i have srw 18's on the truck with 35's.
It shook with 3 sets of back rims. Its definately got a lubed slip joint. I have rotated the shaft several times then balanced it. I could be mistaken but i think its with the rear end. Maybe just e brakes. The clunk i get reverse to drive then again to reverse etc. But it also clunks when I am rolling to a stop. But sounds like from the ring and pinion.(this may not be the shake?.
This truck is now a srw vehicle. I will know soon enough. I sold the rear on ebay. Done with it. I was honest about it. I sold it cheap.
I am more trying to figure out what inside a rear can cause this vibration? Worn clutches? Hanging broken up e brake? i dont know.

 

[JLDickmon]

tell me this..
is the vibration like in time with wheel revolution or is it higher frequency, like what a u-joint would be?