Post-Lift Driveline Vibration-What Spacer?

2018 Tundra Crewmax, 4x4, SR5, 5.7L.

Recently lifted. In the rear, there are 2” lift shackles and a 1” block. I installed the driveline drop spacer that came with the shackles, which is roughly 3/8” thick. I am getting a driveline vibe that starts at low speeds, gets bad around 20mph, tapers off, gets bad from 40-50mph, and then goes away. It isn’t a tire; definitely driveline.

When I say “gets bad”, I’m being overly dramatic...it isn’t bad, but I can feel it in my seat. What kind of driveline spacers is everyone running with lifts? I searched and could not find much info on spacer sizing. To be clear, I mean a drop spacer on the carrier bearing, mid-driveshaft.

 

My 2” longer shackles came with a 3/4” spacer for the carrier bearing. Basically I got a 1” lift from the shackles. So if using that formula you are lifted 2 inches. But dropping the driveline and inch and a half seems excessive. I would start experimenting with adding shims until it seems to smooth out.

 

@Coachbuilder1 makes driveline spacers

https://shop-coachbuilder.myshopify.com/

 

Anyone have an idea what size the bolts holding the carrier bearing are? I’ll need to get longer ones...

 

The stock bolt is long enough to add about a 1” spacer.

 

Solved: I tried 1” spacers and it was better, but not perfect.

My local Ace Hardware had M10x1.25 bolts, 70mm long, and some 1.5” thick-wall spacers. Those worked perfectly, and there are no vibrations of any kind now.

Again, I have 1” blocks and 2” shackle lift. 1.5” spacers worked perfectly for me.