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new lift- extreme vibes at 10 mph

WJACKSON11X

WJACKSON11X

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I did a search but didnt find the exact thing I was looking for. I just installed ORD 4" shackle flip with 1" zero rates in rear and front 4" TC springs, All greasable bushings and ORD super shackle and HD front shackles. When I got done with the lift and went for a test drive, I couldnt get above 10 MPH due to very bad vibes. I went ahead and changed rear u-joints and it still drives the same. After reading some threads, I think my pinion angle is off, I included some pics to help out.What do you guys think?

HEAVY CHEVY 001.JPG

HEAVY CHEVY 002.JPG

HEAVY CHEVY 003.JPG

HEAVY CHEVY 004.JPG
 
Looks like you have to drop the t-case still. That top joint on the slip yoke looks close to binding up...That looks like your problem. To do this, just flip the spacers around.

Here`s a reference pic from obijuan:

IMG_2309.jpg
 
yeah, I havent dropped the transfer case yet, do you think this will sove my problems? BIGBLAZE, do you still have the stock driveshaft? and did you experience the heavy vibes with a 4" lift?
 
WJACKSON11X said:
yeah, I havent dropped the transfer case yet, do you think this will sove my problems? BIGBLAZE, do you still have the stock driveshaft? and did you experience the heavy vibes with a 4" lift?
Click to expand...
It should. Check and make sure your ujoint is still good, too.

Yep, still using the stock driveshaft, and I get a little vibration, but I suspect its a worn u joint and worn bushing on the tail shaft.
 
alright, since last post I went out and dropped the transfer case. one thing I noticed is when I cranked it up, im now getting a shaking sensation when its in park, never done that before. It did help on the vibration a bunch, but I still have one. Does dropping the transfer case put a bind on the engine/transmission? sorry Im new to all this, Ive lifted other vehicles but never had this problem.

I can now drive it at about 40 mph. alot better than it was.
 
Check your motor mounts. I have had my tcase dropped for 6yrs now using the factory 1" spacers. You need to get an angle finder and see what angle the pinion is setting at and what angle the tcase output is. IIRC they should be within a couple degress of each other. You may have to shim the rear end accordingly or worst case scenario a rear CV driveshaft. I had to get a rear CV driveshaft but that is only because I had more lift.
 
i had the SAME deal you got VIBES after lift. dropped the t-case saved 70% vibes but a horrible racket and a grinding inside the cab i could even feel in the gas pedal,..... turns out my oil sending unit and my cruise box along with the rod that shifts the tranny was all against the firewall. . relocated everything and adjusted shift linkage everything fine now,.... i am goin to a cv shaft monday to see if that cures the remaining vibes
 
Your whole problem is u-joint angles. The top pic would be perfect if you had a CV shaft back there. Also you need to grind the stops out of the front CV before you explode the front shaft. Dropping the t-case will help with your vibes but at the same time compouding the front shaft angle with the stops. They will bind with 4" of lift. The back you'll need some degree shims installed or get a CV rear shaft.
 
Maybe a stupid question, but do I need to shim it up or down? meaning does the rear diff need to point more up or down? sorry im new to all this. Maybe I should just grow some and buy a CV shaft.
 
I had the same issue after my 4" lift. Tried shimming things, but no fix. I finally broke down and bought a rear cv shaft from H.A.D. and put the transfer case back to stock location. There is absolutely NO vibrations now. You do need to get an angle finder and get your readings like was already said though.
 
not to hijack, but im going to be doing a 4 inch lift this spring and is it possible i might have this problem? The point to be doing the 4 inch was no to mess with the drivetrain much, am i gonna need to move around the tcase or mess with the driveshafts? Thanks.

/hijackoff
 
Thanks for everyone's responses, sounds like I just to go the CV route. It'll probably save me money and repairs in the long run. Ill let yall know how it turns out.
 
You need to point the pinion more "down" to answer your question. Your driveshaft should work with a 4" lift without much problems if your angles are correct. But even if you do get angles right... if your slip yoke is pulled too far out of the t-case... you will have issues when the rear suspension droops... as in driveshaft falls out the t-case.

The angle of the pinion should be appx. 1 or 2* lower than the t-case output... to account for axle wrap when you press the skinny pedal.

You can use an angle finder and a socket that fits flush against your U joint caps to find angle. Truck must be level... then do this:

1: Arrange the driveshaft so that a U joint cap attached to the pinion yoke is flat surface down... use socket and angle finder to find pinion angle.

2: At the transfer case output you can usually just put the angle finder against the slip yoke (or use socket + angle finder method if fixed yoke) to find the t-case output angle.

3: Need to shim to make angles equal... or even better, when the pinion is lower by a degree.

With a CV joint shaft, you want the pinion pointing at the t-case output... but again low by a degree or so is good due to axle wrap.

Google "driveline angles"... tons of info.
 
Its kinda already been said but:

You need to lower your pinion angle. The operating angle for the two joints on your driveshaft need to be the same or you will get vibrations.

The problem is that Spicer also says that the max angle for a vibration free shaft is something like 3 degrees (yours is more like 15 probably). This is why many people have to use a cv shaft to eliminate vibration.



Using the stock "spacers" to drop the t-case will cause your frame to crack. Not to mention that dropping the t-case makes your front driveshaft angle worse. You can try messing with the pinion angle but I bet you will need a cv shaft to get rid of the vibes.
 
blazerbones said:
Chris,

Could you elaborate on this? Kinda wondering what your experience with this may have been.
Click to expand...

It concentrates stress on that area of the frame. It didn't happen to me (I've never lowered my t-case) but there have been a few people (here on ck5) that have had their frames crack in that area because they used those spacers under the frame. I'll see if I can find them.

The correct t-case drop spacers would look more like body mounts.
 
Go ahead and get a double cardan shaft.

You can try running a single cardan but it will require shimming the rear axle down several degrees and lowering the xfer case. Please do not use the factory spacers to lower the case - one hard hit on the xmember and the frame will bend or crack due to leverage - use rectangle or solid stock. The front driveshaft will require clearance grinding either way.
 
what would a rear cv shaft cost? I know everywhere is different, but just a ballpark figure would do. some say single cardan shaft and some say double cardan shaft, which is better?
 
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