Bad vibes after lift install - Solved? Solved!

[thezentree]

Doesn't adjusting the upper control arm (and pinion angle) rotate the whole rear end assembly? I would think this would affect the seating of the rear springs and shocks, or is the rotation not enough to be significant?

It does, but it's a relatively insignificant amount. I think I added ~3/8" to the UCAs?

The right way to do it would obviously be to weld new mounts on the axle, but if it comes to that, it's come time to swap in bigger axleS.

 

[Stone128]

Are the rear UCAs hard to install? I'm assuming since it is the rear there is no need for another alignment after. Are the lower UCAs required at all?

Did your vibration change depending on ambient temperature? This one has me puzzled the most.

 

[thecole1098]

Lower Control arms are not necessary, unless you actually are doing some hardcore wheeling that requires thicker arms. The only thing the lowers do is center the housing in the wheel well, which is why after a lift, the tires will appear further towards the front of the vehicle when looking from the side. The upper control arms is what rotates the housing, thus affecting pinion angle. Lastly, the panhard bar is what centers the housing side to side when looking from behind the vehicle. Our rigs are a 5 link system in the rear.

 

[thezentree]

Are the rear UCAs hard to install? I'm assuming since it is the rear there is no need for another alignment after. Are the lower UCAs required at all?

Did your vibration change depending on ambient temperature? This one has me puzzled the most.

Eh, I guess it depends on which ones you get. The johnny joint on the MetalTech UCAs I have are a little wider than the stock UCAs, so you have to open the frame mount up a little to get them in. The hardest part is getting everything aligned to get all your fasteners back together but if you can install a lift, you can do the UCAs. Keep weight on the wheels and only do one side at a time. [MENTION=136902]thecole1098[/MENTION] is right about the lower control arms - you don't really need them unless you're breaking them on the trail.

As for my vibration, I don't know if it was temperature dependent or northbound lanes being rougher than southbound lanes or what, but it did seem like it was regularly worse on my afternoon commute home for whatever reason.

I've actually still got a slight vibration that was barely noticeable this morning and was slightly worse this afternoon (still much, much better than it was). Given how sensitive the vibrations are to vertical pinion angle changes, I wonder if me having the factory panhard bar in is causing a slight misalignment. Going to swap the Rokmen panhard I have in the basement back in on Friday and see if it helps any.

 

[Stone128]

The baffling thing to me is that others will lift to 3" and past with no vibes at all. I talked to a driveline shop and they said 3" shouldn't be enough to cause pinion vibes.

 

[thezentree]

The baffling thing to me is that others will lift to 3" and past with no vibes at all. I talked to a driveline shop and they said 3" shouldn't be enough to cause pinion vibes.

Yeah I don't understand how so many others don't have this issue. I will say though that with mud tires on mine, the harshness of the tires totally drowns out the driveline vibrations.

I measured about 5° difference in pinion angle at first, which is outside the 3° or less that Tom Woods recommends. Making the UCAs ~3/8" longer reduced that to around 1.5-2°, so maybe our rigs are seeing the effects of tolerance stack with the mount points? I'd imagine that Toyota controls their assembly processes much better than that though.

 

[Stone128]

I dropped the rear drive shaft today And drove up to 60mph. My low speed accelrstion occilating drone/hum went away completely and I had 0 vibrations. All ujoints felt solid in the rear driveshaft so it's either shaft balance, pinion angle, or a bad ujoint that isn't obvious. I am going to regrease up all joints and clear out slip yoke of built up grease. Only other options look like adjustable rear upper control arms, take rear driveshaft to a shop for balancing and rebuild, or lower the lift.

 

[thezentree]

I dropped the rear drive shaft today And drove up to 60mph. My low speed accelrstion occilating drone/hum went away completely and I had 0 vibrations. All ujoints felt solid in the rear driveshaft so it's either shaft balance, pinion angle, or a bad ujoint that isn't obvious. I am going to regrease up all joints and clear out slip yoke of built up grease. Only other options look like adjustable rear upper control arms, take rear driveshaft to a shop for balancing and rebuild, or lower the lift.

If you had no vibrations before installing the lift then it's not a balance issue. Maybe bad U-joint or double cardan, but my money is on pinion angle.

 

[Stone128]

Driveshaft is back in after being regrease and all slip yoke grease buildup removed. Vibes are almost non existent now but I need to do some more driving in warmer weather to confirm it's not just the colder temp giving me false positives. Did you ever get you panhard bar back in? I'm contemplating buying a Sonoran Steel adjustable.

 

[thezentree]

No I ended up not swapping it back in. The frame to outside tread block measurement was so close I couldn’t tell a difference so I didn’t want to push the axle to one side if it’s already pretty centered.

 

[Stone128]

So my vibes are worse than ever today and it's directly correlated with warmer weather. I'm about ready to cut my losses and go to 99 tall springs instead of messing with pinion angle to find out that's not it. My last ditch effort is to throw 500 lbs in the rear to simulate a different pinion angle first.

 

[Stone128]

So my vibes are worse than ever today and it's directly correlated with warmer weather. I'm about ready to cut my losses and go to 99 tall springs instead of messing with pinion angle to find out that's not it. My last ditch effort is to throw 500 lbs in the rear to simulate a different pinion angle first.

Measured pinion angle and it's about 4ish degrees.

 

[thezentree]

I didn't start noticing any real reduction in vibrations until like 2-2.5° FWIW.

 

[Stone128]

Any thoughts on UCAs?
metal tech vs rokman vs the ones linked below?

https://frontrangeoffroadfab.com/4runner-upper-links-3rd-gen-rear/

 

[thezentree]

I actually bought a set of Rokmen UCAs, left them in my basement for two weeks, and returned them so I could order Metal Tech UCAs. The Rokmen were well made and seem like a good product, but for a salt belt DD I didn't want to deal with heims.

The Metal Tech UCAs are great, but they only make them in limited numbers and not frequently. If you want a set you need to email them and check if they have them in stock and if not, when they plan to do a run of them. I'm really happy with them though. They're priced reasonably and are a great product.

 

[Stone128]

I am in the salt belt as well. My only concern with the metal techs is that I've been reading they don't fit well? Does the install damage the mount points?

 

[thezentree]

Yeah the johnny joints are like 1/16" too wide so you will probably have to spread the frame side mounts a little.

 

[Stone128]

I tried to install my metaltechs today and got Johnny joint into the frame but I can't get the bushing part down in the axle mount. Any suggestions?

There is literally no way the bushing will fit into the axle mount...it is almost 1/4" larger than stock. This can't be correct...I'm going to contact metal tech and hope they just sent me the wrong ones.

 

[thezentree]

Figured I'd update this since I still can't figure this vibration out, and it has started to get worse in the last couple of weeks.

Thinking the TW driveshaft was still slightly bent, I replaced the U-joint in the OEM driveshaft thinking I could swap it back in and see if it smoothed out. No luck, but while it was out I was able to get a really good pinion angle measurement and realized I had set pinion angle to almost exactly 0°, so I backed it back down to ~1.2° so the needles in the u-joint don't get worn flat.

I hadn't noticed much of a difference between the OEM and TW driveshafts, but just to definitively rule it out, I took the TW driveshaft back to the local shop and had them check it. They said it was about .025" out of round (same as last time, when I sent it back to TW), so they straightened and balanced it. I went for another front wheel drive trip around down while the driveshaft was out, and there is definitely a bad vibration from the front above 50mph but it feels much different than the one I'm normally getting in 2WD. I think that's probably front pinion angle from the diff drop, but I don't know for sure. In FWD it does feel like all of the vibration is coming through the steering column though.

After swapping the TW driveshaft back in and driving it to work and back since Tuesday, it feels like it has gotten progressively worse. I'm not confident that the local driveline shop (Fleetpride) got an accurate measurement initially and may have not completely straightened it or even bent it more. Unfortunately they're the only shop in town, so it is what it is. I guess I'm just going to put the OEM driveshaft back in and see what happens, but the fact that the vibration through the seat and floorpan totally disappeared in front wheel drive makes me not trust that one either.

I'm considering trying to track down some old CVs to cut apart so I can totally isolate the front diff, but even if that stops the vibration, I'm not sure how to fix that since it's done it with three separate sets of CVs.

tl;dr - damn it.

I tried to install my metaltechs today and got Johnny joint into the frame but I can't get the bushing part down in the axle mount. Any suggestions?

There is literally no way the bushing will fit into the axle mount...it is almost 1/4" larger than stock. This can't be correct...I'm going to contact metal tech and hope they just sent me the wrong ones.

Sorry, I just saw this. I am assuming you've figured something out by now, but the rubber bushing end on mine fit really tight in the axle mount, but it definitely is not 1/4" too big.

The johnny joint, however, was oversized and I had to open the frame mounts up a little bit to get them in.

 

[SDmtnbkr]

Dude, I've been randomly watching this thread over the last few months hoping for a resolution. I'm in nursing school so I can barely think, let along track down my own vibration issues.... but it seems like mine is very similar to yours!

Stock truck felt great. Stock with new 265 Duratacs were just as good (5k mile road trip from SoCal to Banff and back with not a single vibration or noise. I ordered a full King suspension with 650# springs (normal is 600#)in anticipation of a plate bumper and winch, so naturally it lifted the truck a little more than it was supposed to, but nothing crazy.... INSTANT major vibrations. Like crazy vibrations, and I couldn't tell if it was passenger or driver.

After searching I realized it was likely the CV angle. I forgot to measure what my stock height was, but post lift my Hub to Fender measurement was 22 3/4. So I turned the coils down 8 turns to 21 1/8 and the the vibrations almost completely went away. I turned them up maybe another 1/2 in and I can feel the vibrations but I kind of block them out and don't really notice them.

I got a Napa remanufactured CV axel to replace one of the sides and see if it fixes the problem, and if not, switch it over, but after reading your comment I might just have to keep it as a spare. You never posted photos of the comparison.... could you post them? I'd really appreciate it.