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#1 |
Senior Member
Join Date: Aug 2003
Location: Sugar Land, TX
Posts: 1,007
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new leaf springs are changing differential angle
I bought 2" lifted superlift springs for my suburban lift. Now, I'm getting driveline vibration. I'm convinced it's because the springs have a metal piece at the axle that looks like a doorstop. It angles the differential upward and makes it so the driveshaft is almost straight with the differential and therefore the u-joint is almost straight.
On the other hand, the upper u-joint by the carrier bearing is obviously at an angle. From everything I've read, you need the same angle at both ujoints to cancel the vibration. Why do the springs do that?? If they had a flat bottom instead of the "doorstop" shaped piece, I think it would be fine. Do just the superlift springs do this? Do I have any options?? Thanks! |
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#2 |
Senior Member
Join Date: Jan 2003
Location: daytonabeach
Posts: 22,956
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i don't know much about lifted vehicles but can you just turn the springs around to reduce the angle??
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71c-10 350/2004r/4:11 lowered3/4 longbed/dead by hurricane MEANING OF DEATH::::: SOMEBODY ELSE GETS YOUR STUFF DONT BELIEVE EVERYTHING YOU THINK TAKE MY ADVISE;I DON'T USE IT ANYWAY |
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#3 |
Registered User
Join Date: Jan 2004
Location: Redding, CA
Posts: 148
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My 8" skyjackers had a 4* wedge. I had to remove it because of the vibration.
If operating angle is any kind of issue for your truck, you could lower the transfer case to match the rear angle.
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2006 Ram 3500 4x4 CTD 6 Speed 73 Chev K30 Flatbed 91 Jeep YJ 58 Jeep CJ5 See my pics: http://www.flickr.com/photos/18032714@N08/ |
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#4 |
Senior Member
Join Date: Aug 2003
Location: Sugar Land, TX
Posts: 1,007
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I can't turn them around b/c they're 56" and the axle is offcenter. I thought of that though... actually I thought for a sec maybe I had them backward.
My truck is 2wd, so no transfer case, but to lower the tranny, I'd need to lower the crossmember for the tranny plus the carrier bearing crossmember and even at that, I still wouldn't have matching angles... I think removing that plate could do it, but that has the little dimple in it to fit into the axle. |
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#5 |
user # 2756
![]() Join Date: Jun 2001
Location: Chesapeake, Virginia
Posts: 4,612
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When you remove the degree shim you could get a new center bolt for the spring pack. The centering bolt is cheap a couple bucks a piece. When was the last time you changed the carrier bearing? The slightly lift could have accelerated wear on it. The blocks on both my trucks (2" and 4") are tapered, but I don't have a carrier bearing. You have 3 u-joints in your rear driveshaft and the carrier bearing, which shaft has 2 u-joints?
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1970 K25, 8' stepside bed 350/465/205 44 up front, 60 in the rear 4.10s rolling on 33" Dunlop MTs 1986 K5, 350/465/208 Dana 60/14 bolt from a cucv 36" Super Swampers TSL/SX 1983 K20 w/ CUCV axles, 350/700R4/208 sitting on 37" Goodyears 1986 M1031 6.2 diesel, TH400/NP205 locker in the rear and a LS in the front, all stock for now..... 1986 K30, 350/400/205 dana 60 and 14 bolt. I kept the drivetrain. Body/bad and chassis are gone. 1981 K30, 350/465/205 dana 60 and dually 14 bolt. Has a G80, and a flat bed. Going to replace the flat bed. 1985 K20, 350/400/208 10 bolt and SF 14 bolt. I wonder where I can find some 1 tons. Hmmmmm ![]() |
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#6 |
runnin on empty
Join Date: Jun 2004
Location: Middle Georgia
Posts: 115
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while I do not have the experience yet with lifted suburbans, I do have a few years on Jeeps of which the Cherokee's are known for what is called the Death Wobble (vibs so bad that you can not hold the steering wheel straight) with lifts over 3 inches.
one way to get the drive shaft lined up right is to get a protractor and find what the measurements are (angle of the drive shaft at the u-joints) at the rear of the tranny and another at the front of the rear axle in stock form (if already lifted have someone with a stock set up let you measure thiers), after the lift is installed you take new measurements - this will let you know how much of a taper you need for some tapered shims that you would install on the axle. depending on the size of the lift you may also need to lower the rear of the transmission and/or install a slip yoke eliminator. Not sure if this is of any help if so and you need a little more info let me know. Gunny ![]()
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88 GMC Suburban - 6.2 Diesel 4x4 87 Jeep Cherokee - 6" lift, 32 bfg's, way too many mods to list. 65 Thunderbird - Stock United States Marine Corps SEPIUS EXERTUS, SEMPER FIDELIS, FRATER INFINITAS "Often Tested, Always Faithful, Brothers Forever" |
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#7 |
Mudslides 'r my specialty
Join Date: Dec 2003
Location: STL
Posts: 1,106
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If the wedge is part of the spring, can you had another wedge to the other side to "cancel" out the first wedge?
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Always on the lookout for old cars and parts...(20s, 30s, 40s, 50s, 60s, etc.) http://www.cardomain.com/memberpage/500339 |
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#8 |
Account Suspended
Join Date: May 2004
Location: Simi Valley, CA
Posts: 1,387
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use shims to correct the angle
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