I pulled the old 86 out of the weeds

trythis

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More information, here's what I did.
First thing I removed the rear drive shaft and check for vibration, ran pretty smooth. That eliminated a lot.
So I'm checking around looking for anything that might be out of order everything seems to be tight and relatively clean so I hooked the rear drive shaft back up but I still have vibration. I should point out this is a high speed vibration.
Then I pulled the axles so that the wheels would not turn but the third member would. Speedometer don't work tack don't work. So I will admit , I am guessing at the speed. I put the truck in 4th gear speed up to what I think is about 2000 RPM that is where the vibration is most obvious. And it is still there. no wheels turning
u joints have no slop.
When I watched the drive shaft spin at high RPM it is bouncing up and down near the carrier bearing or center support bearing.

These vibrations are like trying to find a leak in the roof sometimes you can't see where it's coming from but you know it's there.

OK so I added some weights to the drive shaft and it smoothed out pretty good. I can live with it.

The other problem is the wheels that I put on my new tires do not center up on the hubs the inside diameter of the wheel is 4. 85 inches and the hub is 4.75 inches or less.
The axle come out of a 1984 or 85 and I'm thinking it must need the wheels so use the older cone style lug nut that wedges the wheel in place at the stud. The newer style wheel that I put on centers by center hole.
This must be the major source of the vibration. So I guess I need to find some wheels unless there's an alternative I don't know of. Thanks for taking the time to read the post any advice will be appreciated.
 

trythis

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I did have to balance the drive shaft I'm still not satisfied with that but the major problem I found was the wheels are not right for the axle. that allowed for the wheels to be off center. The rear end out of that truck come from an earlier model they took the earlier model wheels with the wedge shape or cone shape lug nuts. They also have a slightly smaller center. So I'd say I got 90% of the vibration out of it still gonna work on that balance and the drive shaft or have the front drive shaft built by someone else that has the shop to do it. I cut it down when I change the transmission and I thought I got it very close but maybe not close enough. At least now I can drive it and I really appreciate all the help and advice you guys came up with keep up the good work God bless.
 
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