Carrier bearing drop question

I just installed some dobinson leaf springs, which provide 2.1 in of lift. Do I need a carrier bearing drop? If so, how much? I have enough material to make whatever I need, and a mountain of washers as well. I'm about to replace my u joints and carrier bearing so I'd like to have it set up correctly before installing the new stuff.

 

Yes you need to install one.. Having the spacer installed will correct the angle and eliminate the vibration during acceleration from a dead stop. For a 2 inch lift, the carrier bearing drop down that we use from Coachbuilder is exactly 3/4 inch thick. The factory bolts are plenty long enough as well. Torque is 25 foot pounds with the truck on the ground.

 

Awesome! Thank you for the quick response. I'll order that, but make something in the mean time to get me by

 

Just edited my post as you hit like...lol.

 

https://shop-coachbuilder.myshopify.com/products/coachbuilder-carrier-bearing-drop-kit-rear-lift-0-2

 

X2 about 3/4"

 

This is the correct answer and my experience matches

 

Anyone know the max drop you'd want to do on the CB bracket? Just dropped mine about 1.25" and it still has the shudder. I need to measure driveline angles to get some more data but just curious if others have dropped much more than 1.5"

 

What size lift are you running?

 

6" with 35s.

Also thought I read or watched something about leaf spring shims? Was really hoping the CB drop would take care of the shudder but the lift size may require more drop im assuming.

 

There are leaf spring shims but they are for leveling the lean condition. Do you have the diff drop installed?

 

Post a pic of your carrier bearing, please.

 

Yes, the diff drop seems pretty big. Not just spacers but a whole new piece.

Also, just crawled under the truck and measured the spacers they put in. They're just 1" aluminum bar stock with new bolts. Probably needs more based on what I've read.

 

Would you please take pic of your bearing and post it?

The mounting flange of the bearing is offset from the center axis by about 5/8". I can't count how many times I've seen the carrier bearing installed upside down on these forums. That alone will cause major shudder.

 

I have the 2" CB shackles. This is the drop on my carrier. I also run a 6" lift.

 

Thanks for the pic. Just to clarify, thats a 2" spacer you're running?

Here's mine with the 1" spacer. Orientation seems to be correct with the single hole down.

 

No, 3/4". My shackles are 2" lift (1.25" real)

 

Ahh, gotcha. Thanks for clarifying. That pic is deceiving, spacer looks way bigger than the one on mine.

 

Have you thought about decreasing the amount of drop? You may be too low.

 

That may be a good suggestion. Just put it on yesterday and drove about 40 miles.

 

My 6" also has a 3/4" drop with zero shutter.

 

Thanks. I'll try some smaller shims. How much lift you have in the rear on yours?

 

Spicer has a really good guide on their site. It can help anyone dial in their driveline angles.

 

I would say 5"

 

Checked driveline angles and it looks like I am a bit too low on paper.

Working angle at the diff u joint is ~6deg vs ~4deg at CB. Bringing it back up should bring those closer together and bring the working angle closer to 0 at the transfer case. Right now tcase working angle is ~0.8deg.

 

With that much lift, you should add traction bars, pretty sure your problem is axle wrap.

 

The 6/35 setup is pretty common and I can count the time I've seen trac bars on one hand

 

Does that make it right or wrong? Minimizing axle wrap is always a good idea. Pretty sure many of those you see eat u joints faster than they should.

 

Just sayin that I doubt all those trucks are having axle wrap.

 

I was thinking that may be part of the issue since it is worse under heavier acceleration.

I did loosen the bolts and pushed the CB over as far as I could to get better alignment between the driveshafts. Still not completely straight when taping a string to both ends but its as good as I could get it. That alone seemed to help a bit.

Never heard of a traction bar, will need to research.