Drive Shaft Vibrations Solved Step-by-Step

Sweet, looks like I'm going to be angle finding this weekend.

 

Okay guys I need some help here.
I have a very very slight vibe at 22mph

This pic is the difference between tcase flanges and pinion flange.

Looks like 1.7 deg down

Second is the difference between first shaft and 2nd.

Looks like .7 difference.

I'm running ome medium dakars with their CB drop that comes with the kit.

Am I close enough that the vibs might be tires? I've tried spacing the CB down a bit more but it seemed to have no effect. Also the vib is there in 4x4 so not thinking needle bearing.

Google says a 20mph vibe could be an out of round tire.

 

0.7 up or down?

I'm 1.2 up, but will drop the DS and remeasure later today. My DS is toast, so it needs to go to a shop.

 

Thinking down. Need to check that

 

Here are my initial readings:

 

@Oscar I

 

Hey guys found this thread while searching for a solution for my vibrations on my 3rd gen. I have a vibe from 20-25mph and 25-20mph. Rear suspension is king with Dakar medium leaf pack. I had the CB drop installed at the same time as the leaf pack since it came with it. I have since purchased 3* shims to see if that helps. Couple questions installing the shims, I purchased slotted shims that should just slide in, do I need to have the truck on stands to install them? Do I need to remove the wheels? Can I just loosen the Ubolts enough to slide the shim under and install the new leaf back bolt?

 

I can’t see you installing them without putting the truck on stands.

Removing the wheels will give you better access to the leaf packs/axel.

 

They won't just slide in as the trucks weight is on them.
The truck will need to be jacked up and once its jacked up you really should have it on stands for safety reasons.

Don't try and short cut it. Your limbs/life aren't worth it.

 

Thanks, would I need to take out the entire pack?

 

Maybe not due to the cutout design, unless you have to change bolts.

Make sure you use a c-clamp on the springs, so the pack stays together.

 

The shims came with new bolts so I'm guessing I need to clamp them, take out ubolts, take out the middle leaf bolt & replace with longer bolt, then put it all together with the shim under?

 

That depends on the amount of threads left on your original bolt. I would plan for doing just that.

Mine shims are not slotted, so I have to gain enough clearance to remove/replace the bolt (most likely by removing the spring pack).

 

I'm curious, how many people found that they didnt need axle shims? I had zero vibes with a 2.5" lift but have been trying all sorts of shims and cb spacers since going to 3.5" and getting vibes. My pinion is pointed up about 1.5° with 2° shims, so I'm debating removing them altogether and starting over with stacking washers at the cb

 

Alright, today I removed my axe shims and cb shims. With my gauge zeroed on the TC, I have 3.8 first shaft, 5.9 second shaft, 2.2 diff. If I want to point my diff down more to make it parallel to the TC, install shims fat side forward?

 

Yes, but if you point the diff down, you increase the angle on your aft shaft.

Have you measured your diff with the DS removed?

I kept getting a different reading until I did that. Not much, but slightly off.

 

Havent tried that yet, but I've been debating replacing the carrier bearing so that would be a good time to do it. I just cant wrap my head around how I had zero vibes at with my stock leafs plus toytec aal (+1.5"), but now I've been fiddling with it for a year since adding the ome pack (+2.5" I'd guess). I've debated pulling the aal so it'll be the medium duty pack, but with a cap and soon to be tire carrier, I'd like the option to haul more weight

 

I still have my progressive ask and OL spring. My vibe started nearly 2 years after install.
Make sure you don’t have play in the slip joint, behind the CB (inside the aftshaft).

 

I’m experiencing something weird. So I have a 2.5 inch lift. With the OEM tires and wheels I had a vibe from 20-25 and 25-20. I verified that it wasn’t the needle bearing. Now today I finally mount my new wheels and tires, 285/70 so it gave it a bit more lift and the vibrations are gone. Is that possible? My OEM tires were still pretty new (10k miles).

 

A tire may have been out of balance, giving you the vibration.