Morning all,

Just a quick update after installing my 5" readylift rear blocks - had a chance to drive the truck a few miles, and now I have a vibration. Hopefully this information helps someone else

The 5" readylift block (the only one they offer) is tapered roughly 4 degrees.

When installed on my 156" wheelbase crewcab shortbox, it rotates the pinion up so it is almost aligned with the driveshaft. I think this is where my vibration is coming from - the pinion needs to be parallel to the carrier bearing (or transfer case output) to keep the u-joint angles equal.

I contacted Readylift and they themselves said this block was designed for this particular vehicle, however some require a flat block or a carrier bearing spacer. Or another fix would be to add a 2.5 degree shim to the blocks.

Spacing the carrier bearing down would help equal out the u-joint angles, but my pinion still wouldn't be parallel to the t-case (or carrier bearing - the carrier bearing is essentially an extension of the t-case output). I think that is a band-aid fix in my particular situation.

I guess the bottom line is I think I should have gone with a flat block (as per everyone's recommendations on here - duh ). Now I'll either get a 2.5 degree wedge shim for the leaf springs (per what Readylift said) or swap out the tapered blocks for flat ones.

Chalk this up to experience I guess .

I'll let you know how it goes.
Thanks,
Pat

 

If it were me, I'd find a machinist and have the blocks squared up as opposed to stacking a shim on a block. It's very simple and shouldn't cost more than about an hour's labor at any decent shop.

 

Not a bad idea, but the blocks are hollow, and there isn't enough meat to machine away the angle. I'd do it myself on our Bridgeport mill at work, but sadly the block design won't allow it.

Most shims can bolt to the existing leaf spring pack, so they become part of the leaf pack, to reduce the chance of spitting one out. Still, I agree with what you said, I'm not crazy about stacking a shim in there.

I'll figger something out

Thanks!
Pat

 

I am curious as to why so many guys with Super Duty trucks do lift blocks? I guess because it is cheap?

I hate lift blocks, why not do a shackle flip?

Again just curious, I am new to the Super Duty world and don't want to **** anyone off!

 

You said 5" is the only one they offer, I just ordered a 4" block from readylift, came tapered, and just drove 1000 miles after install and had zero issues. Btw my truck is a Supercab short bed. Hope this helps

 

Your vibration is due to drive shaft angle. You need a carrier bearing shim. This restores the drive shaft angle. Not a band-aid at all.

 

I meant it's the only 5" block they offer

Sorry for the confusion,
Pat

 

Yes, I realize this is because of the driveshaft angle. And you are correct that shimming carrier changes the driveshaft angle. However it doesn't change the fact that the pinion isn't parallel to the carrier bearing/t-case. That was kinda my point in my original email.

BUT....the more I think about it, if I can shim the carrier bearing and correct the u-joint angles, then I'll leave the pinion alone. Assuming of course the pinion isn't rotated so far that I starve the front pinion bearing of oil.

Always somethin'

 

any lift kit company gives you shims for the carrier bearing support. ever inch needs 1/4" drop i believe. So you went from 2 1/2" to 5" then you need a 3/4" drop to get back to the stock angle

 

and the rear has a oil sling thats suppose to sling oil to the upper pinion bearings, but with that much pinion angle it might not get the proper lube im not sure

 

also since the angle is steeper you can just fill the rear axle with more fluid till it comes out of the fill hole. this will bring the level back to the pinion bearings

 

That's what I was thinking also. I think I'll start there, easiest thing to do.

I'll fab up my own shims in our shop, no biggie.

Thanks everyone for the replies!
Pat