About 2 weeks ago I installed KORE's "chase" system on my truck. Ive noticed theres a slight shudder that seems to coming from the rear of the truck when I take off. The only time it doesnt happen is at extremely low speeds.

Ive followed IGOR's thread about his shudder and vib but he seems to have a different problem.

Anyone else have this happen w/ the KORE system? Any ideas as to what it could be?

Thanks,
Jeff

 

Longbox, right?

Seems that most longbox trucks have more problems then short box trucks from my searches.

Explain the shudder or vibe?

 

yep its a long-box.

The shudder happens right on take-off, up till about 10 mph at certain throttle levels. Almost feels like Im driving a bogger-tired truck for a second.

Could it be a tire problem? Id think an out-of-balance tire would show itself at higher speeds.

Thanks for any help you can give me

Jeff

 

Have you tried shimming the carrier bearing yet? Seems most LB vibs has been cured by throwing a shim or two in there.

 

Shim the bearing or add a set of ladder bars. Mine did the same thing after my lift and I put on a set of ladder bars and the problem went away. My roommate has the same lift on his longbed and his shudders real bad.

 

I would say shim.

But,

Tuff country ladder bars? How much???

I might not be able to add them with my airbags, unless, I fab some more brackets.

Where do they bolt onto the axle?

Thanks.

 

On mine they bolt to the front u-bolts and then again to the frame. But my u-bolts face the ground and yalls face the sky. I paid $350 for mine from rockymountainsusp.com. I really like them. They really locked everything down and make the truck very stable. And whoever says you can't flex with ladder bars is lying to you. I've stuffed my rear tire completely into the fender with them on there without even so much as a creak or a groan from them.

 

Hmm, im not gonna lie, im sorta confused about the whole shim thing

anyone care to explain?

 

To shim your carrier bearing means to put some kind of shim/spacer between the frame and the carrier bearing.....resulting in less driveline angle and not binding per say the rear u-joint.

If that makes any sense to you.

bill

 

HERE is a pretty good discussion of pinion angle setup. Just remember - with a carrier bearing, you have 2 driveshafts to deal with.

Rusty

 

alright, I sorta understand what you guys are talking about now, but I'm still confused as to exactly how I go about doing it. What would I use?

 

I put my money on the rear axle u-joint angle (pinion angle in relation to the driveshaft). I've seen some people turn the pinion up to where it's almost in line with the driveshaft. When you take off from a stop the pinion goes up a few degrees from the springs flexing.

Can you take a picture of that?

Andy

 

with a cv shaft ( two ujoints in a ball socket) you do want to turn the pinion up parrallel with the driveshaft. actually a degree or three lower is optimal for when you acclerate the pinion rotates up.

when you have one ujointat the transfercase (or carrier bearing) and one at the axle, you need the pinion angle and the fixed upper part ( ie the t case output flange or in this case the carrier bearing is the fixed point) to be parrallel. when u joints turn at an angle they really dont turn smoothly. they sorta wobble. the best way to understand this is to take anaxle shaft and stub shaft and turn them in your hand. As the joint turns, it turns fast and then it turns slow, fast then slow. With two aligned joints, they cancel out vibrations and bad harmonics. So if your carrier bearing joint and pinion joint are out of sinc, then you get a vibration.
So sometimes shimming the carrier beaing don will bring things back into alignment. however this can be tricky cause now ou may start to lose sinc between the t case and carrier bearing though since there is no movemnet between the two, a few degrees there wont kill it.
most likely a few pieces of flatstock steel with some longer bolts should work as a shim but im not really sure how the dodge carrier bearing mounts.

EDIT: ah the beauty of thr internet. http://www.suspensionconnection.com/...on/20824D.html

 

Well, this is exactly what I have but a pro comp version. But its not enough for me.

However, the reason I think its not enough is because

a) I have airbags and although they don't lift the truck anymore, the stiffen stuff up

b) mainly because of that tranny bracket to help out the front diff. Again, I think this is a problem a shortbox would not have.

So I thik I need to shim my carrier bearing down some more. Perhaps one more of these "shim" kits and some longer bolts will do it. BUT, the question is, what happends when I start adding some power or get stuck somewhere and have to give it some good throttle off the line. Will that be strong enough?....

My I have shudder on takeoff, that is worse with more throttle...and that was WAY worse when I had no shim.

My top end vibration is more like a "whoom, whoom" hum/vibration that also gets worse if I am into the throttle heavy.

 

Sorry its taken me awhile to get back to the thread but.......

I see what yall are talking about w/ dropping the carrier bearing. Unfortunately Ive recently moved and havent unpacked the camera so I cant take a pic for u RealSquash.

How long before I do any serious damage by driving on it like this? I dont have the time right now to fix it unless I really have to. Has anyone else w/ just the KORE lift had this happen? I think Im goin to give them a call to see what they say about it.......the lift wasnt cheap for the small amount of clearance gained and I know they pride themselves on everything working together correctly.

thanks again
Jeff