Vibration In Lifted '89 K5

[89BLAZ]

I WAS WONDERING IF ANYONE COULD HELP ME OUT? I HAVE A '89 K5 LIFTED WITH 8" SUSPENSION KIT. I AM RUNNING 35" TALL TIRES WITH ALL THE NECESSARY DROP BRACKETS(SWAY BAR, TRANSFER CASE). I HAVE A REAL BAD VIBRATION THAT FEELS LIKE IT IS COMING FROM THE TRANSMISSION-TRANSFER CASE AREA. THE DRIVESHAFTS HAVE BEEN BALANCED. THIS ONLY OCCURS UNDER LOAD AND HAS DONE SO SINCE I LIFTED IT. I HAVE HAD IT LOOKED AT AND THEY TOLD ME I NEEDED TO DROP MY CASE DOWN MORE. I HAD 1" SPACERS AND NOW I HAVE APPROX 1 1/2". IF I DROP IT ANY MORE IT LOOKS LIKE MY TRANNY WILL HIT THE FLOOR. PLEASE CAN ANYONE SHEAD SOME LIGHT ON THIS SUBJECT....I REALLY DON'T WANT TO GO TO A 6" KIT TO GET RID OF THIS PROBLEM.


THANKS,
SEAN

[Mudder]

Sounds like you have a bad angle on your driveshaft. Or it could be a tire. Are you tires balanced? Are the front and rear yokes on the driveshaft in phase? I guess thats what ya call it???? Pinion nut loose? What kind of tires and how big? Oh how is the slip joint? Is it pretty much extended out?

[89BLAZ]

The Tires Are Not Balanced...but Really Is Not A Tire Vibration...you Don't Feel It In The Steering Wheel, Just From The Floor Boards And Seat. Slip Yoke Is Fine. It Was Extended Out Too Far Then I Had The Shafts Lenghtened. The Other Stuff I'll Have To Check. So The Joints Have To Be Lined Up Together...i Would Say Mine Are Not. Thanks For The Help...i'll Check It Out.

Thanks,
Sean

[freightdriver]

how much of that lift is blocks? i'm saying its a drive shaft vibration and you either need to get your rearend turned or a dual cv driveshaft to correct it
i've got 1.25in of tcase drop and a dual cv driveshaft 4in springs and 4.5 blocks i've ran it up to 95 with no vibrations. hope you get it fixed getting the rearend turned is roughly aound 250 and my dual cv shaft was 350..
oh and i'd go back to the 1in tcase drop all its doing is making your front driveshaft angle worse...

[89BLAZ]

ALL OF THE REAR IS BLOCK (5.5) WITH A ADD A LEAF. I Tried Using Degree Shims But That Really Didn't Help. The T-case Drop Redused The Vibration...but Not Completely. Thanks Oh By The Way...nice Color On The Blazer...mine Is Orange Too. Pictures Are Too Large To Download...but It Is In Image Gallery On Home Page.

Thanks Again,
Sean

[kwmech]

You may have to get a slip yoke eliminator kit from www.jbconversions.com
Then you can put a cv rear shaft in.

[89BLAZ]

thanks for all the helpful info....keep them comin. i am going to look into these suggestions.

thanks again,
sean

[Richard]

I am guessing that the pinion is turning up to much under a load, partially because of the tall blocks. Try shimming the pinion down instead of up (just a couple of degrees). An add-a-leaf and a shorter block may help as well. Springs and no block would most likley cure the problem. I had an 85 shortbed with custom 10" leafs front and rear. Did not have a slip-yoke elim kit. Put around 60,000 miles on it with the lift, no vibration problems. Really no driveline problems at all once I used Spicer u-joints. The slip-yoke kit is a good upgrade though.

[89BLAZ]

Would This Be A Product Of The Shorter Wheelbase On The Blazer? If This Kit Was On A Shortbed Or A Long Wheelbase Truck Would I Still Have The Problem?


Thanks,
Sean

[freightdriver]

yes its due to the driveline being so short if i remember my ds is about 37in long, shortbeds etc would not have the problem we're faced with i suppose its one of those cons to owning a blazer with that much lift...

[freightdriver]

please do everyone a favor that drives on the road and do not put both a block and degree shim in.. since none of us can see your angles maybe lookup a driveshaft shop around your area and drive it down there and see what they say

[89BLAZ]

I AM NOT USING THE SHIMS ANYMORE. IT WAS A TRIAL BY ERROR BASIS. I TALKED TO SOMEBODY AT A LOCAL DRIVELINE SHOP AND THEY ARE THE ONES THAT SAID MY T-CASE NEEDED LOWERED MORE. THAT IS WHY I POSTED...IT IS NOT THAT FUN TO DRIVE LIKE IT IS.

THANKS,
SEAN

[freightdriver]

i did'nt mean to be a jackass about it, the whole thing just frightens me lol.. ..if it was a ds shop i don't see why them damn fools would keep telling you to make drop the tcase more and more but anyways idk are there any 4x4 shops or other driveline shops around that might be more alittle bit into 4x4's? someones going to have to see the angles to be able to tell what has to be done. maybe give this guy a call www.highangledriveline.com 530-877-2875 ask for jesse

[89BLAZ]

If I Remember Correctly..i Think They Were 5 Degree. Really There Were No Change In The Vibration. It Seems Like No One Around Here Knows What Is Wrong???? I've Got A Lot Of Good Ideas Now. So Do You Think By Getting Rid Of The Blocks And Going All Spring...would That Help?

Sean

[freightdriver]

look at my post again i added a website and phone number that guy should be able to get you setup...

[Richard]

Going all spring would most likley help with axle wrap if that is the problem. That is why I suggested shimming to play around with the angles. The short driveline can definitly be a problem but you should be able to get a good compromise. My brothers Jeep with a smallblock 700R4 and spring-over only had a 14" rear driveline. The angle was pretty steep compared to my SB truck and he drove it all the time on the highway. The rear driveline was nothing special in the way of high angle components. It is all about the angles. Maybe try putting the pinion end just below inline with the shaft. Also check your U-joints again. Make sure they are quality units. The cheaper ones use larger needle bearings which means less bearing surface area. As freightdriver said not a good idea to use shims and blocks in the long term. You can purchase shims that will bolt to the spring pack with the center bolt though. I always use them when I get the angles where I want them. I have had rear springs made for my last two trucks though.

[special-K]

I suggest springs too,no blocks.I`d also suggest 6".That extra 2" is your bigger culprit.Unless you are planning bigger tires that require an 8"lift,you don`t need all that lift.If your not going to get into alot of twisty stuff,you can actually loose 4" and still run 35s.To each his own,but I don`t get too wild with mine and I love the way it feels on the road,stable.I have 33s(1" less axle clearance),10 rims,and no lift.I just had the spring shop level up the front(helps handling,also)and add a leaf.Like I said,to each his own.I lift trucks,too.I was going another approach with this Blazer.Probably not your cup o`tea.Just trying to add some perspective.