Rear adjustable lower control arms (1 Viewer)

ghost2466

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I need some guidance here guys. I recently installed the Iron Man foam cell lift kit w/ diff drop on my 98. After the install I noticed a pretty hard vibration coming from the front end around 60-70mph only when accelerating. It goes away when you let off.

I had a leaky driver side CV axle (non-factory) so I went ahead and swapped it out with a fresh one from Toyota. The vibration is still present. Reduced but still present. I dropped the rear driveline and locked the center diff and did a road test just to isolate the problem as there seems to be some vibration coming from the rear.

My questions are as follows:
1: Passenger side CV axle looks to be in great shape. Could this CV axle be the problem? Maybe just worn in and doesn’t like the 2” lift? I’ve already ordered another Toyota CV axle to replace it.

2: There a little vibration coming from the rear. Would adjustable lower control arms help this? Necessary?

Any tips or suggestions is appreciated.
 
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I need some guidance here guys. I recently installed the Iron Man foam cell lift kit w/ diff drop on my 98. After the install I noticed a pretty hard vibration coming from the front end around 60-70mph only when accelerating. It goes away when you let off.

I had a leaky driver side CV axle (non-factory) so I went ahead and swapped it out with a fresh one from Toyota. The vibration is still present. Reduced but still present. I dropped the rear driveline and locked the center diff and did a road test just to isolate the problem as there seems to be some vibration coming from the rear.

My questions are as follows:
1: Passenger side CV axle looks to be in great shape. Could this CV axle be the problem? Maybe just worn in and doesn’t like the 2” lift? I’ve already ordered another Toyota CV axle to replace it.

2: There a little vibration coming from the rear. Would adjustable lower control arms help this? Necessary?

Any tips or suggestions is appreciated.

most information points to the aftermarket CV joints causing vibrations. Rear adjustable arms will always allow you to fine tune your pinion angle to ensure that it’s correct. If your going for perfection check out metal tech or trail tailors arms
 

ghost2466

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most information points to the aftermarket CV joints causing vibrations. Rear adjustable arms will always allow you to fine tune your pinion angle to ensure that it’s correct. If your going for perfection check out metal tech or trail tailors arms
The passenger side CV is aftermarket (previous owner installed it). Weird thing is I never had the vibration before the lift kit install. I went factory when I replaced the drivers side. I ordered another factory CV from Toyota for the passenger side.

I hoping the CV axles were just worn in and don’t like the lift. Either way both of them are now going to be factory Toyota CV axles.

Just reaching out for tips. I’m hoping changing the passenger CV axle does the trick. Getting real tired of looking at the underside and fender wheels....

That’s a lie. I love my 100 and enjoy working on it. I’m tired of hearing my wife nag about me working on everyday for the last 2 weeks 😎
 
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The passenger side CV is aftermarket (previous owner installed it). Weird thing is I never had the vibration before the lift kit install. I went factory when I replaced the drivers side. I ordered another factory CV from Toyota for the passenger side.

I hoping the CV axles were just worn in and don’t like the lift. Either way both of them are now going to be factory Toyota CV axles.

Just reaching out for tips. I’m hoping changing the passenger CV axle does the trick. Getting real tired of looking at the underside and fender wheels....

That’s a lie. I love my 100 and enjoy working on it. I’m tired of hearing my wife nag about me working on everyday for the last 2 weeks 😎

could be most who have issues with aftermarket CVS are lifted and that causes it to vibrate? Nevertheless the rear can be fixed by installing upper control arms but if you want it done 100% replace the uppers and lowers. Your factory bushings are probably worn out anyways
 

abuck99

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Have to agree its prob the aftermarket CV- some of them don't run smoothly when lifted.

nearly every single person running adjustable rear arms is running them at factory length... they even use the factory links to set the length....

Count me as the (1) not running factory length on upper and lower trailing arms. Not sure why anyone would waste the coin on adjustable arms if they didn't actually plan to adjust them.

FFT- If OP installed Ironman Springs, these are 80 series 2" lift springs which on a 100, puts it closer to 3"with out bumper or drawers - that extra inch will cause the rear pinion to nose down a couple of degrees and depending on how worn the TC mount is and how worn the trailing arm bushes are and U joints are that might be enough to cause some driveline vibes under acceleration. You want TC pointing DOWN and rear pinion pointing UP /-----/. ideally where the combined difference is 1 degree- (up to a maximum of 3 degrees) difference ( subtract the TC flange angle from pinion angle). Now if all the trailing arm bushes are worn, TC mount is worn that's enough to also effect pinion movement, especially when power is applied. If rear Ujoints are worn the new driveline angles, as minimal as a few degrees might seem, will also contribute vibes. Front DS runs pretty level , so chances of that being the contributing issue is pretty low.
 

Somebodyelse5

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Have to agree its prob the aftermarket CV- some of them don't run smoothly when lifted.



Count me as the (1) not running factory length on upper and lower trailing arms. Not sure why anyone would waste the coin on adjustable arms if they didn't actually plan to adjust them.

FFT- If OP installed Ironman Springs, these are 80 series 2" lift springs which on a 100, puts it closer to 3"with out bumper or drawers - that extra inch will cause the rear pinion to nose down a couple of degrees and depending on how worn the TC mount is and how worn the trailing arm bushes are and U joints are that might be enough to cause some driveline vibes under acceleration. You want TC pointing DOWN and rear pinion pointing UP /-----/. ideally where the combined difference is 1 degree- (up to a maximum of 3 degrees) difference ( subtract the TC flange angle from pinion angle). Now if all the trailing arm bushes are worn, TC mount is worn that's enough to also effect pinion movement, especially when power is applied. If rear Ujoints are worn the new driveline angles, as minimal as a few degrees might seem, will also contribute vibes. Front DS runs pretty level , so chances of that being the contributing issue is pretty low.

Yup, you are most definitely one of the few running arms at a different length! you've gotta be different :rofl:

I will add though, no one "should" be running 3" of lift in the back unless they are going for that stink bug look.
 

ghost2466

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Have to agree its prob the aftermarket CV- some of them don't run smoothly when lifted.



Count me as the (1) not running factory length on upper and lower trailing arms. Not sure why anyone would waste the coin on adjustable arms if they didn't actually plan to adjust them.

FFT- If OP installed Ironman Springs, these are 80 series 2" lift springs which on a 100, puts it closer to 3"with out bumper or drawers - that extra inch will cause the rear pinion to nose down a couple of degrees and depending on how worn the TC mount is and how worn the trailing arm bushes are and U joints are that might be enough to cause some driveline vibes under acceleration. You want TC pointing DOWN and rear pinion pointing UP /-----/. ideally where the combined difference is 1 degree- (up to a maximum of 3 degrees) difference ( subtract the TC flange angle from pinion angle). Now if all the trailing arm bushes are worn, TC mount is worn that's enough to also effect pinion movement, especially when power is applied. If rear Ujoints are worn the new driveline angles, as minimal as a few degrees might seem, will also contribute vibes. Front DS runs pretty level , so chances of that being the contributing issue is pretty low.
Thank you for the feedback. They are Iron Man springs. I’ll check into what you said tonight!
 
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Have to agree its prob the aftermarket CV- some of them don't run smoothly when lifted.



Count me as the (1) not running factory length on upper and lower trailing arms. Not sure why anyone would waste the coin on adjustable arms if they didn't actually plan to adjust them.

FFT- If OP installed Ironman Springs, these are 80 series 2" lift springs which on a 100, puts it closer to 3"with out bumper or drawers - that extra inch will cause the rear pinion to nose down a couple of degrees and depending on how worn the TC mount is and how worn the trailing arm bushes are and U joints are that might be enough to cause some driveline vibes under acceleration. You want TC pointing DOWN and rear pinion pointing UP /-----/. ideally where the combined difference is 1 degree- (up to a maximum of 3 degrees) difference ( subtract the TC flange angle from pinion angle). Now if all the trailing arm bushes are worn, TC mount is worn that's enough to also effect pinion movement, especially when power is applied. If rear Ujoints are worn the new driveline angles, as minimal as a few degrees might seem, will also contribute vibes. Front DS runs pretty level , so chances of that being the contributing issue is pretty low.
I recently added the Tough dog tourflex heavy lift with all the goodies: shocks, springs, sway bar extensions, diff drop, adjustable rear upper&lower control arms and a set of nitro front UCA's and happen to be running 3/8 in longer than stock upper and lower rear control arms. My pinion/ds angles are neutral as in 5deg down from ds/ 5deg up from differential.

My rear DS slip yoke is now sitting about 1 inch longer than before, as evidenced by the shiny part now exposed.

At 65-75mph I get buzzing vibration on acceleration that's worse on a climb on the freeway. This wasn't an issue before the lift.

I'm in the process of chasing the culprit. Any advice would be appreciated.
 

ghost2466

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I ended up purchasing 2 new OEM axles and the vibration went away. I went down the same road as you. I even had my driveline balanced because I wasn’t willing to accept that there is a difference between CVJ axles and Toyota OEM.

Have you had your driveline balanced? Have you checked that the unjoints are aligned correctly? I had the same exact symptoms as you.
 
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I ended up purchasing 2 new OEM axles and the vibration went away. I went down the same road as you. I even had my driveline balanced because I wasn’t willing to accept that there is a difference between CVJ axles and Toyota OEM.

Have you had your driveline balanced? Have you checked that the unjoints are aligned correctly? I had the same exact symptoms as you.
Thanks for the reply.

No I haven't had the driveline balanced. I believe the u joints correct, in phase. I just pulled them out last night and greased the snot out of them.

What's puzzling is the fact that I get vibes with either shaft removed. Very weird, but it could mean all my old u-joints are tired.

AFAIK the CV's are original OEM. If I have to replace those...I guess I can.
 

ghost2466

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Thanks for the reply.

No I haven't had the driveline balanced. I believe the u joints correct, in phase. I just pulled them out last night and greased the snot out of them.

What's puzzling is the fact that I get vibes with either shaft removed. Very weird, but it could mean all my old u-joints are tired.

AFAIK the CV's are original OEM. If I have to replace those...I guess I can.
Where does it feel like your vibration is coming from? Do your CV’s have a yellow band on the boot? That would indicate factory CV’s unless the PO had them rebooted.

Does it feel like the front is hopping a little? It could be the torsion bars are over-cranked. Maybe lower the front end a bit and see if the vibration decreases before dropping 1100 bucks on Toyota CV’s.
 
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Where does it feel like your vibration is coming from? Do your CV’s have a yellow band on the boot? That would indicate factory CV’s unless the PO had them rebooted.

Does it feel like the front is hopping a little? It could be the torsion bars are over-cranked. Maybe lower the front end a bit and see if the vibration decreases before dropping 1100 bucks on Toyota CV’s.
I'll check for original vs aftermarket. I have a reboot kit for both both CV's that the PO included, but not sure that the CV's have been changed.

No hopping in the front.

I can also lower the front a bit. I'm sitting at 21.25" hub to fender, per lift kit instructions. I was hoping the diff drop would have eliminated the need to run lower than 21.25", but perhaps not.

I'm 23" hub to fender in the rear (heavy 660# constant springs) though I'm not fully loaded in back at the moment, so that should compress when my gear is loaded, and my aux tank goes in and is full.
 

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