highway speed vibration

[OCMike]

I've starting noticing a little vibration when I'm traveling at highway speeds and gently let off the accelerator. It goes away if I take my foot completely off though. Nothing rough, but I can feel something. Any idea what it might be? My runner is an automatic 4WD 3.slow.

 

[SV_Dude]

Keep your foot off of the accelerator...??

Get your tires balanced.

 

[GonOvr]

Sounds like driveline float.

Check your driveline, pinion, and t-case output for play. Grease or replace as necessary.

 

[OCMike]

Tires are balanced. It only happens when I feather the accelerator.

 

[OCMike]

Sounds like driveline float.

Check your driveline, pinion, and t-case output for play. Grease or replace as necessary.

Nate, I'll have my mechanic check that next time I take the truck in for service. Could that affect my mpg also? Have been noticing a drop of about 2 mpg over the last 4-5 months.

 

[GonOvr]

No that shouldn't effect the MPG. Just your tolerance and patience. If it gets worse, stop driving it. It could end up being catastrophic.

 

[Bad_Vision]

u joints?

 

[77'911]

We had the same, but it was a combo of issues. Costco improperly balanced the tires(don't have the proper centering mandrel for the balancer, unique to 4runners) which then had to be done by another co. I replaced the drive line mounts(engine and trans) which reduced the vibrations markedly. The last iteration that killed off any and all stability or vibration issues on the highway, was rebuilding the suspension with urethane bushings. The ones in the rear(ie rear lateral rod, rear control arms) really make quite a difference.
regards