2018 4Runner - Severe Vibration in Steering Wheel When Letting Off Gas at Highway Speed

[dan50]

2018 4Runner - Severe Vibration in Steering Wheel When Letting Off Gas at Highway Speed​

2018 Toyota 4Runner Limited, 113k miles, 1GR-FE 4.0 liter V6 engine, A750F 5 speed automatic, VF4BM electric full time transfer case with torsion center diff, second owner (since ~90k miles), original bushings, control arms, shocks/struts, U joints, etc. POS tires that came on it when I bought it; balanced 8k miles ago, new rotors/pads/stainless steel lines/brake fluid 5k miles ago. I aligned the vehicle 5k miles ago (1 deg thrust angle to the left, front wheels aligned with the thrust angle, 2/32” toe-in total, 1/32” per wheel, which is what I’ve always run my 5.0 liter Mustang at. I hope that’s enough detail.

Last night when returning from dinner, a severe steering wheel shimmy appeared when I let off the gas after merging onto the highway. Speed was ~60 mph and the shimmy was present at any speed between 50 and 70 mph when letting off the gas. Getting back on the gas eliminated the shimmy. Severe enough that I was wondering if my lug nuts had backed off. Does not appear, or I couldn’t detect it, at speeds under ~40 mph. Was NOT present on the drive TO dinner 90 minutes earlier. Never been an issue before last night, either.

What should I look at? It’s not the lug nuts.

 

[gomiami]

2018 4Runner - Severe Vibration in Steering Wheel When Letting Off Gas at Highway Speed​

2018 Toyota 4Runner Limited, 113k miles, 1GR-FE 4.0 liter V6 engine, A750F 5 speed automatic, VF4BM electric full time transfer case with torsion center diff, second owner (since ~90k miles), original bushings, control arms, shocks/struts, U joints, etc. POS tires that came on it when I bought it; balanced 8k miles ago, new rotors/pads/stainless steel lines/brake fluid 5k miles ago. I aligned the vehicle 5k miles ago (1 deg thrust angle to the left, front wheels aligned with the thrust angle, 2/32” toe-in total, 1/32” per wheel, which is what I’ve always run my 5.0 liter Mustang at. I hope that’s enough detail.

Last night when returning from dinner, a severe steering wheel shimmy appeared when I let off the gas after merging onto the highway. Speed was ~60 mph and the shimmy was present at any speed between 50 and 70 mph when letting off the gas. Getting back on the gas eliminated the shimmy. Severe enough that I was wondering if my lug nuts had backed off. Does not appear, or I couldn’t detect it, at speeds under ~40 mph. Was NOT present on the drive TO dinner 90 minutes earlier. Never been an issue before last night, either.

What should I look at? It’s not the lug nuts.

Hard to say over the Internet but, if there is no noise (just steering wheel vibration,) it is a wheel or tire problem. You can probably eliminate a bent wheel fairly easily with a visual inspection. Same with tire damage, looking for bulges or uneven wear. A tire or wheel imbalance can't be seen, only felt and the recent balancing doesn't mean anything.

If the tires are junk, a new set with proper balancing...

 

[Trumpet]

Tie rod end(s) or a faulty caliper.

Mine was both, calipers were locked up and a tie rod end was shot.

 

[Talyn]

I thought I read that the front 4wd bushing can cause this as well?

Most likely another issue.
But I know my steering components are tight, and I've gotten a weird steering vibration in mine a few times, its not consistent though.

There is a lot of things that can cause a steering wheel vibration.

 

[gomiami]

In my experience, bushings, calipers and the like that are failing will make noise. He didn't report any...only vibration at a specific highway speed.

Talyn is correct, though. There are a lot of things that will cause a vibration through the steering wheel.

 

[Talyn]

I do get a random vibration in my steering wheel, but its really random and makes no sense.
I just attributed it to the 4wd bushing on mine which needs to be replaced.
Actually I get a lot of odd vibrations in my 4runner that I'm not sure enough about yet.

Brake issues like hung calipers are generally easy to figure out because your stopping gets weird. It will hang on one side and pull, or the pedal response will be really weird with how it brakes.

Stuff like brake bushings dont generally make vibrations unless they are falling out or missing.

And he did report the steering issue is at a slow down speed. In my experience, that's an alignment issue with tires and/or bad tie rod end. Where when we take forward force off it wiggles, but the forces have to be just right.
But the 4wd bushing thing could still be the thing too where when he slows down at that speed, it has a weird drag vibration. and/or cv joint failing.

CV joints are really hard to detect for issues when they are just starting to go, lot easier to find when they really bad.

 

[ArthurKotb]

Tie rod end(s) or a faulty caliper.

Mine was both, calipers were locked up and a tie rod end was shot.

Many years ago I had this happen on an old car I got for free. The symptoms were exactly as described by the OP so I agree on the tie rod ends (or whatever they're using these days). I replaced the tie rod ends and problem was solved.