Alright everyone, buckle those seatbelts. This is gonna be a pretty detailed post.
To give a little background, what I'm feeling is almost like the bed is bouncing or "fluttering" on something like that. The bed feels like it has a lot of up and down, and maybe trapezoidal movement (forward and backward, like a rhombus).
I've been still struggling with this for the longest freaking time (since I've had the truck).
I started going through and thinking what might be the problem. I started off with since maybe the tires were so old (like 12+ years) they probably needed to go. I had 3 different tires on the truck, so I got 4 new tires and that did not solve the issue. Even after a rebalancing.
Prior to this, I replaced the shocks. I used Gabriel for the front and rear, specifically these for the front (Gabriel 61634)
and these for the rear (Gabriel 61600)
. I'm not sure if these are good or bad, but they're what I have installed.
After dealing with the problem for a while (after new shocks and new tires), I shifted to changing the bushings for the leaf springs and replacing the rear hangers and leaf spring shackle. I thought maybe because the bushings were completely seized, the springs weren't compressing properly and then was causing the axle to shift or wrap. That doesn't appear to be the case.
Problem is still occurring after this.
So I have three main videos (and then a few others if anyone wants to see). These videos were taken AFTER I replaced the leaf spring components (as well as new tires and shocks).
Here is a video of the rear suspension looking forward. I've cut out some of the extra video and only focused on a section where the vibration is the worst. I think you can see it bouncing up and down and shifting left and right a bit.
This next video is taken with the camera mounted to the cab pointed at the box. I added some red reference lines so you can see how much the bed is bouncing around.
This last video is what various parts of the body look like with the tires spinning off the ground. I was doing this to find out if the tires were horribly balanced and causing vibration. I can feel a little
bit of vibration in the cab and bed, but it's minimal. You can also see a little deflection in the drive shaft, but again not that much.
I checked the runout at some point on the axles and I remember it being very minimal. I can go check this again but tit was within spec I think.
So now I'm sitting here pulling my hair out trying to figure out what this could be. Is it something with the cab? Something with the bed? My friend is suggesting to take a look at the body mounts, but it looks like the bed doesn't have any bushing mounts? Does it just attach directly to the frame then? Looking online and in the manual, it looks like there are only bushing mounts for the cab.
Someone please help me and save my sanity.