Do I need to Adjust my Pinion Angle? Icon Stage 6

[JimJr15]

I have about 2500 miles on my 2018 T4R since I installed the Icon/Metal Tech Stage 6 Kit.

My rear springs are the 2" 52700s. https://www.metaltech4x4.com/icon-2003-current-4runner-2-lift-rear-coil-springs/

I've noticed a noise that only occurs when I'm on the gas or the truck is engine braking. I can actually make it stop by creating a situation where there is no load on the drive train in either direction. I don't recall this in my 2015, but I never paid much attention since that truck didn't have a lift.

When I bought the lift back in 2015, (which I never installed on my 2015 T4R) I vaguely remember buying the Metal Tech adjustable rear links in case I needed to adjust the pinion angle, but I can't remember for sure.

It's not very loud, but I can notice it. Is it possible this is some type of Universal Joint noise and I need to adjust my pinion angle? Here's the best pic I can get of the Drive Shaft/U-Joint

 

[JSparky]

Anything is possible, although at 2” it’d be uncommon. Regardless, since you already have adjustable uppers installed, tweaking the pinion would be the easiest and cheaper first step.

With the factory rear driveshaft you want that pinion as close to 0 degrees as possible. Find a flat level surface to park and use an angle finder to take measurements, then adjust from there. You can usually eyeball it pretty close. It goes without saying that you want to take all these measurements with the vehicle supporting itself, not on jack stands.

 

[JimJr15]

While i'm perfectly capable of adjusting the rear links mechanically, I don't have any experience with the process.

Do I adjust the upper and lower equally?

Is there a ratio of adjustment upper to lower? (for example: 2 turns on the upper rod ends for every one turn of the lower)

I would imagine that to rotate the diff so that the pinion points upward, one would lengthen the upper arms and equally shorten the lower arms, as to not push the entire axle rearward?

 

[fourwd1]

Anything is possible, although at 2” it’d be uncommon. Regardless, since you already have adjustable uppers installed, tweaking the pinion would be the easiest and cheaper first step.

With the factory rear driveshaft you want that pinion as close to 0 degrees as possible. Find a flat level surface to park and use an angle finder to take measurements, then adjust from there. You can usually eyeball it pretty close. It goes without saying that you want to take all these measurements with the vehicle supporting itself, not on jack stands.

^^^^ This.
It should be parallel with the ground.
It's hard to tell in the pic, but it might be pointed upward just a little.
But you just mention a little noise, typically a bad pinion angle will cause vibrations. Even then only at specific rpm and/or mph.

 

[JimJr15]

But you just mention a little noise, typically a bad pinion angle will cause vibrations. Even then only at specific rpm and/or mph.

I describe it as more of a growl/very slight vibration felt in the floor/seat

 

[tacoyota]

I highly doubt just a small 2 inch lift will affect the driveline or pinion angle. Something else has to be the issue. That noise sounds like possible u joints or your diff. I would try greasing your zerk fittings along the driveline first and then possibly changing out your rear diff fluid. It is odd though since your truck is brand new....

 

[JSparky]

Hold, on.

There is some misleading info here.

There is a lot of different ways to measure pinion angle in terms of what it relates to... These trucks have a CV rear driveshaft. So the pinion angle of the diff flange should be 0 compared to the drive shaft angle (not the ground). It should tilt up and point directly at the tcase flange... Picture better than words....

These angels are constantly changing. One thing you can try is to put some weight in the back and see how that impacts it... If you find a spot where it smooths out. Adjust ride height to that angle.

Maybe I’m mistaken, but I’m pretty sure this image describes the factory rear driveshaft, at least on my Limited. It’s a two-piece, I know because I just replaced it with a double cardan/CV.

 

[JimJr15]

I highly doubt just a small 2 inch lift will affect the driveline or pinion angle. Something else has to be the issue. That noise sounds like possible u joints or your diff. I would try greasing your zerk fittings along the driveline first and then possibly changing out your rear diff fluid. It is odd though since your truck is brand new....

Yes, I agree with everything youre saying. The noise and vibration is very slight and I even wonder if it's normal and I'm somewhat hyper sensitive to it due to trying to notice if fanything is out of the ordinary due to installing the lift.

I don't recall this from my 2015, but I never purposely looked for it.

 

[Gt4r]

Sounds like it could be your front diff bearing. Most people feel it around 40 mph. If you put it in 4h does the growl go away?

 

[wfo9]

Maybe I’m mistaken, but I’m pretty sure this image describes the factory rear driveshaft, at least on my Limited. It’s a two-piece, I know because I just replaced it with a double cardan/CV.

My bad. I got my trucks mixed up since I have a double on the other one.

I was thinking the 4runner did also.

So yea, the differing planes will cause some slight velocity change (A slight growl of sorts). Could be something else though, but that is the entire point of setting pinion angle with a single joint non constant velocity drive shaft.

I need to get a double on there at some point or adjust my pinion angle. I don't really have a noticeable growl at the moment. Maybe a tad. The advantage of the double is you get better clearance for wheeling. It may seem small, but it makes a big difference in my experience. Unfortunately, custom drive shafts are super expensive.

You want the two flanges (T-case/diff) on matching planes with a single. Sorry for the confusion about the trucks coming with a double from the factory.

 

[JSparky]

My bad. I got my trucks mixed up since I have a double on the other one.

I was thinking the 4runner did also.

So yea, the differing planes will cause some slight velocity change (A slight growl of sorts). Could be something else though, but that is the entire point of setting pinion angle with a single joint non constant velocity drive shaft.

I need to get a double on there at some point or adjust my pinion angle. I don't really have a noticeable growl at the moment. Maybe a tad. The advantage of the double is you get better clearance for wheeling. It may seem small, but it makes a big difference in my experience. Unfortunately, custom drive shafts are super expensive.

You want the two flanges (T-case/diff) on matching planes with a single. Sorry for the confusion about the trucks coming with a double from the factory.

No worries, it’s funny because I went through this last week. I guess there’s a new, lower profile 1310 flange our for Toyota’s which is nice, it lets you keep the factory studs on the transfercase output. I had to swap them out for nuts and bolts when I installed a cv on my cruiser a few years back. And yea, the driveline was over $400.