HELP drivetrain vibration

[Shahnp1]

I've been working on raising my truck up a little bit change from3/5 to a 2/4 drop.

So today I finished the backend, reinstalled the factory load leafs in the leaf spring packs, everything went smoothish or so i thought.

I get everything finished and leave the shop i was working on my truck at and something is not right at all. I can feel a slight vibe through the shifter and when i accel it increases to a shake, it also feels like my truck has a damn boat anchor or a the whole damn boat dragging behind it. it just feels sickly.

I'm not real sure what it could be the only thing that changed was the addition of the leafs, the pinion angle looks ok so i don't. this F-ing blows balls....

????Could it be caused by a u-joint going out causing a vibration in the driveline in turn causing the Knock Sensors to go all crazy and pulling out timing under load. IDK exactly how all that really works?????

IF anybody has any idea please post it... there's nothin worse than finishing a project and it go south on ya its kinda like a kicked in the nuts
pic before adding leaf

pic after

[AKlowriderZ71]

What all did you do to your truck right before this vibration started? Did you have the driveline disconnected? Did you have the rear wheels off? Tell us everything that you changed this time around, front and rear.

[Shahnp1]

i took the rear wheels off
dropped the rear end, removed the u bolt to gain access to the leafs
unbolted shocks in the rear
disconnected driveshaft from rear end left the front of shaft in transmission btw its manual trans
I think thats everything
also removed the pinion shimes out since we where lifting it back up, i have had pinion angle problems before but this feels way different
we didn't touch the frontend
everything looked ok on final inspect before we took it off the lift, its usaully a simple process, hell i didn't even test drive it before i headed home

[AKlowriderZ71]

If I had to guess, it sounds like maybe your rear driveline u-joint is not centered and tight in the rear axle yoke. Any possibility of a loose wheel or a park brake cable misrouted/bound up?

[AKlowriderZ71]

Nice looking truck, BTW.

[Shahnp1]

I'll be checking those first thing in the morning... My parking brake is really hard to push in since all this but i didnt make the mental connection lol maybe thats the problem.

thanks for the comp. i need to up load some pics of the whole thing some time

[NITROUS]

You have clips that go on the bearing caps that center the rear U-joint in the yoke. Make sure they didn't come off and have the U-joint misaligned like AKlowriderZ71 said. How much pinion shim did you pull out? Just trying to get all the info we can.

[Shahnp1]

With the 5in drop it had a total 6 degree a 4 and a 2 stacked on top of each other.

after returning to 4in i pulled all the shims out just to see where it would set and by using the infamous eyeball technique it looks ok but its a deffinently a change from what it was. I wonder if the change of the angle in general has revealed a bad rear ujoint they have about 90,xxx miles on them the last time they where replace was from a broken driveshaft new ones came on it from the dealer

i got pics of the way the shims looked before the swap if that helps any i can load them up?

the clip things where in place when i put the shaft back in, keep the questions coming i'll answer everything that i can

thanks again, Shahn C.

[r6z4o6]

I would put the rear axle up on jackstands, and accelerate and have someone looking around to visually check for the vibration. Then take the wheels back off and see if its still there. Perhaps a lugnut didn't seat correctly. Its hard to figure it out unless you see what's going on from below the vehicle.

[TXsilverado]

buy a 10 dollar angle finder from harbor freight or northern tool and forget the eyeball method. the naked eye cant see 2 or 3 degrees.