6" lift driveline vibes?
01-16-2009, 04:30 PM
#1
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6" lift driveline vibes?
My '95 4runner has a 6" suspension lift, 4" coils and 2" spacers. It gets really bad vibes from about 60mph up, I was wondering if anyone else has had this problem, and where could I find adjustable upper links to fix it? thanks
01-18-2009, 08:04 AM
#2
Sounds like either too extreme of drive shaft angle or that the angles of the flanges is off. http://www.4crawler.com/4x4/CheapTri...l#Measurements explains both problems he also sells shims but do the measuring first. If memory serves me seems like 11* is all a single cardigan will tolerate. If you don't fix it you'll wind up with other problems like bearings. Hope this helps.
01-18-2009, 05:17 PM
#4
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Even with a double cv joint you really still need to adjust the pinion angle at the rear drive shaft (shims).
Ideally you want all the angle at the double CV and no angle at the regular u-joint.
Fred
Ideally you want all the angle at the double CV and no angle at the regular u-joint.
Fred
01-18-2009, 05:34 PM
#5
Most will tell you that 4* is as much shim as you can safely run for the road. To rotate the pinion you'll need to cut off spring perches and weld new ones on at right angle (pinion pointing at t-case output). Best if you go ahead and make all desired mods first: ie dual t-cases and drive train lifts. So you only need to do this once. Measure first maybe a shim will fix it. I doubt it but possible.
01-18-2009, 05:51 PM
#6
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Most will tell you that 4* is as much shim as you can safely run for the road. To rotate the pinion you'll need to cut off spring perches and weld new ones on at right angle (pinion pointing at t-case output). Best if you go ahead and make all desired mods first: ie dual t-cases and drive train lifts. So you only need to do this once. Measure first maybe a shim will fix it. I doubt it but possible.
With coils you can simply get adjustable control arms and set the pinion by adjusting the upper and lower arms.
On TJ's (Jeeps) with a much shorter wheel base than the 'Yota trucks and 4Runners, you can run 6" + of suspension lift without a problem that way.
I'm sure the same would be true with 2nd and 3rd gen. 4Runners.
Actually, re-reading the original post, he has coils.
Just need to get or make, some adjustable control arms.
You'll probably need to go to a double cardon joint rear driveshaft.
Fred
Last edited by FredTJ; 01-18-2009 at 05:52 PM.
01-18-2009, 05:59 PM
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you could just go hydrostatic drive and not have any joints at all... 
or maybe a wheel is slightly out of balance or out of round, or a rim is not concentric....
or maybe a wheel is slightly out of balance or out of round, or a rim is not concentric....
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01-19-2009, 08:07 PM
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does anyone know where i can get adjustable links? I didnt think of the wheels not being concentric, they are mickey thompson classics, and I already changed tires thinking that was the problem. ill try changing to a different set of wheels and tires.
01-20-2009, 08:06 PM
#9
Is the 6" lift new? Did you recently add to an existing lift? Was all well and good and then you hit a curb, big pothole, or chunk of debris in the road at aspeed? Read 4crawlers write up, measure the drive line, I had issues with less lift than that. A magnetic base angle finder from habor freight is like $5 and will suit this task fine. Not even worth the effort of swapping out tires if either of the first two questions are yes and if the third is no. Just my $0.02
01-20-2009, 08:18 PM
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ive noticed it seems to be worse on asphalt roads than on concrete... and the whole car always vibrates, even at slow speeds, it just gets worse on the highway. so im thinking it might not be the driveline, or maybe a combination of things? could it be suspension related? because it rides really rough too, maybe the torsion bars?
01-20-2009, 08:29 PM
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You could be over-extending your driveshaft, more lift requires the driveline to be effectively longer. You have less spline connecting the driveshafts, and over time that can wear irregularly and cause some problems. Double-check your u-joints, keep everything greased and chec your motor & tranny mounts. Then start correcting driveline angles & perhaps have a new driveshaft built.
Good luck & don't ignore those bad vibes...
ETA-- PS TJ-- How many control arms and/or control arm bushings have you had to replace? Leaf springs are the bees-knees bomber business... I speak as the prejudiced past owner of a cj-5, cj-7 & a YJ on 1-tons with an early bronco 4-speed and d-20 tcase...
Good luck & don't ignore those bad vibes...
ETA-- PS TJ-- How many control arms and/or control arm bushings have you had to replace? Leaf springs are the bees-knees bomber business... I speak as the prejudiced past owner of a cj-5, cj-7 & a YJ on 1-tons with an early bronco 4-speed and d-20 tcase...
Last edited by AZ89LONGBED; 01-20-2009 at 08:36 PM.
01-21-2009, 04:08 AM
#13
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its always vibrated like that ever since i bought it with 4" of lift. i thought it might have been tire tread so i changed tires, but no effect. i even put lockout hubs on it to keep the cv's from spinning. ill look at all the bushings.
01-21-2009, 05:11 AM
#14
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I made some HD adjustable lowers (1/4" wall DOM and Johnny Joints) to lengthen the distance. As your dif drops it pulls forward in the wheel well. I have a 2" lift and I notice a vibration almost immediately after I installed it and I only had a 2 degree difference in my two angles. I calculated that if I lengthened my lowers by 5/16" it would equall out the opposite angles and return my wheels closer to center.
01-21-2009, 12:41 PM
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would it be safe to remove the rear drive shaft and drive 60mph in front wheel drive? and it has drops on all the links in the rear, but wouldnt i need to shorten the lower links to angle the pinion up? or lenghten the uppers?
01-21-2009, 02:57 PM
#16
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I made some HD adjustable lowers (1/4" wall DOM and Johnny Joints) to lengthen the distance. As your dif drops it pulls forward in the wheel well. I have a 2" lift and I notice a vibration almost immediately after I installed it and I only had a 2 degree difference in my two angles. I calculated that if I lengthened my lowers by 5/16" it would equall out the opposite angles and return my wheels closer to center.
By re-centering the rear tires in the wheel wells when sitting level you've possibly created another problem for yourself.
Look at what the axle does as it articulates.
It moves rearward as it stuffs.
By moving the axle rearward when it's sitting level, you may now have the tires getting into the rear of the wheel well when the axle stuffs.
A lot of people simply don't take the time to look at what the axle does, that is now it moves, though it's whole range of motion.
The axle does not simply move up and down, but it moves forward and backwards (viewed from the side) also. It moves in an arc as it articulates.
Leaving the rear arms the stock length insures that the tires will never get into the end of the wheel well, as the axle will move rearward to the same point that it did before the lift.
Use longer upper arms to push the pinion angle upwards or short uppers to drop the pinion angle.
Fred
01-21-2009, 04:04 PM
#17
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You haven't thought this through very well, have you ?
By re-centering the rear tires in the wheel wells when sitting level you've possibly created another problem for yourself.
Look at what the axle does as it articulates.
It moves rearward as it stuffs.
By moving the axle rearward when it's sitting level, you may now have the tires getting into the rear of the wheel well when the axle stuffs.
A lot of people simply don't take the time to look at what the axle does, that is now it moves, though it's whole range of motion.
The axle does not simply move up and down, but it moves forward and backwards (viewed from the side) also. It moves in an arc as it articulates.
Leaving the rear arms the stock length insures that the tires will never get into the end of the wheel well, as the axle will move rearward to the same point that it did before the lift.
Use longer upper arms to push the pinion angle upwards or short uppers to drop the pinion angle.
Fred
By re-centering the rear tires in the wheel wells when sitting level you've possibly created another problem for yourself.
Look at what the axle does as it articulates.
It moves rearward as it stuffs.
By moving the axle rearward when it's sitting level, you may now have the tires getting into the rear of the wheel well when the axle stuffs.
A lot of people simply don't take the time to look at what the axle does, that is now it moves, though it's whole range of motion.
The axle does not simply move up and down, but it moves forward and backwards (viewed from the side) also. It moves in an arc as it articulates.
Leaving the rear arms the stock length insures that the tires will never get into the end of the wheel well, as the axle will move rearward to the same point that it did before the lift.
Use longer upper arms to push the pinion angle upwards or short uppers to drop the pinion angle.
Fred
01-21-2009, 04:43 PM
#18
[QUOTE=James Dean;51036624]Moving my wheel back half the distance of 5/16", which is only 5/32", to correct my pinion angle, is an acceptable solution. My wheels never come any where close to touching, even if I fully compressed my suspension. My lower links sit at a 14 degree angle with only about a 3-4" difference in height from the front and rear connection point. That means that once my suspension compresses 4" it would actually start moving the diff back forward. This minor calibration reduces wear and tear on every other part of the driveline (especially u-joints) and suspension. My plan is to make HD adjustable uppers as well, then I can make the corrections on both links. Even when I go with 32X11.50's, 5/32" longer lower links will not cause any rubbing issues.
QUOTE]
Nice post, I haven't dealt with links so this is kinda greek to me. What will/would happen if you were to lengthen the links while keeping the axle position the same as your current. Of course you'd need new link to frame mounts, but would this yeild more flex provided the springs can handle it. Or would you have to refigure the axle position.
I'm still and will be for a long while running leaves so this is only food for thought?
QUOTE]
Nice post, I haven't dealt with links so this is kinda greek to me. What will/would happen if you were to lengthen the links while keeping the axle position the same as your current. Of course you'd need new link to frame mounts, but would this yeild more flex provided the springs can handle it. Or would you have to refigure the axle position.
I'm still and will be for a long while running leaves so this is only food for thought?
01-21-2009, 05:02 PM
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you couldn't lengthen the links without affecting the axle position.
imagine a trapezoid where the upper side corresponds to the upper arm, the lower side corresponds to the lower arm, the left is a line between the chassis mounts for the upper and lower arms and the right is a line between the axle mounts of the upper and lower arms, and the axle is approximately mid-way between those.
if you lengthen either the upper or lower arms the axle will rotate and shift towards the rear.
imagine a trapezoid where the upper side corresponds to the upper arm, the lower side corresponds to the lower arm, the left is a line between the chassis mounts for the upper and lower arms and the right is a line between the axle mounts of the upper and lower arms, and the axle is approximately mid-way between those.
if you lengthen either the upper or lower arms the axle will rotate and shift towards the rear.
01-21-2009, 05:36 PM
#20
you couldn't lengthen the links without affecting the axle position.
imagine a trapezoid where the upper side corresponds to the upper arm, the lower side corresponds to the lower arm, the left is a line between the chassis mounts for the upper and lower arms and the right is a line between the axle mounts of the upper and lower arms, and the axle is approximately mid-way between those.
if you lengthen either the upper or lower arms the axle will rotate and shift towards the rear.
imagine a trapezoid where the upper side corresponds to the upper arm, the lower side corresponds to the lower arm, the left is a line between the chassis mounts for the upper and lower arms and the right is a line between the axle mounts of the upper and lower arms, and the axle is approximately mid-way between those.
if you lengthen either the upper or lower arms the axle will rotate and shift towards the rear.
