Hi John. Nice to see you again.

I agree. Has to be something in the driveline, aside from the tires. putting it up on jackstands and spinning things might tell the tale.

 

I had the rear drive shaft out and put in new u-joints and the shop said everything was balanced. As for the front drive shaft I figured it didnt effect anything since it doesnt spin while in two wheel drive.
I did notice a slight bounce /vibration with the stock tires but thought it was because they were worn out. It was amplified when I put on new bigger tires.
At this point I think pulling out the axel is my next step. This has been an on going issue and has three mechanics dumb founded.

 

Hey Brian, good to see you too.

I was actually referring to the rear axle shafts that go from the diff to each rear hub. I was doing some searching and that came up quite a bit as a cause of vibration. Try googling "bent axle shaft" and see if any of it sounds familiar. I don't think it's all that common, but as you say, it has three mechanics stumped so it seems as if we're stuck with "the unusual" for culprits. And again, I wonder if whatever took out the front driveshaft (before you bought the truck) might have tweaked other parts of the driveline. Maybe a Carfax is in order, given what you've already been through.

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One other thought: I don't recall reading that the diff pinion bearing/nut has been ruled out. I'd have to think it would have been noticed by now if the nut had come loose, but I mention it because I know firsthand that a loose pinion nut will give you some fine vibrations. I'm familiar with the full range of them, because I once ignored them ('86 Ram 250) to the point that the pinion nut dropped right into the diff at speed. I have since learned that turning up the volume on the radio is no substitute for preventive maintenance.

 

Have you checked the rear wheel bearings yet?

 

I havent checked the rear bearings yet. It definitely is something up front and haven't worked towards the rear yet. I did put new u joints in the drive shaft. Have you guys heard of this on the 2500's. A mechanic told me that sometimes when you go to a heavier duty shock that you have to use a bigger bolt/screw ? He said that sometimes the opening on the shock is bigger than stock so the stock bolt will cause a space intern causing the shock to have play.

 

If the front shocks are torqued down properly, there shouldn't be any play. After all, them guys are supposed to be torqued to like 100 ft/lbs.

 

funny i am having a vibration too, i am thinking it has something to do with the rear leaf springs. the springs are sitting on the overload. it has the double stacked blocks but the new leafs are the bds 4.5 lift springs. so hopefully that will eliminate the bounce.

 

I have been real busy with work and have a kid on the way so I havent had time to go through my truck again. A mechanic who is friends with the family took a quick peek at my truck and came up with this solution. Change my rear shocks. He noticed that I had replaced the fronts with heavy duty Munroe shocks and was running old Skyjackers in the rear. He pushed down on the corner of the rear bumper and when he released it the entire truck shook , he did this on both sides and you could really see the cab rocking just by pushing it down once. His idea is that the front and rear shocks have different standards and are working against each other. Thoughts on this guys ?

 

Shocks just control the axle. They don't cooperate with each other at all, or, work against one another. More likely is, the rears are just worn out.

 

Has anyone figured this out. I am going threw the same issue. Did the rear shocks work. I have rebuilt alot of the front end trying to fix this problem too.