Hum/Growl/Vibration at 70MPH while stepping on Gas
 

After getting a new engine and new tires -- 318,000 miles on my 1997 4Runner 4WD I notice that it vibrates a TON at 70mph and faster. At first I thought my new tires, Goodyear Wrangler's, were causing the noise or something tire related. I called a few Toyota experts - watched all the YouTube videos I could find and called Yota1 Performance (thanks Nick and crew you rock!) -- and since the noise didn't happen when the truck was on the hoist and ONLY HAPPENED WHEN ON THE GROUND AND I WAS STEPPING ON THE GAS -- it came down to these 4 possibilities --

Wheel Bearings
Driveline
Torque Converter Shudder (but rpm's didn't flutter so I didn't think it was this)
Front or Rear Differential Bearings

With this checklist in hand (all the experts I talked to agreed it was one of these things) the quest to solve the mystery began.

First shop was a differential shop and they said rear diff bearings were shot so replaced them along with shims.
Hop on Freeway after replacing the rear diff bearings and noise is still there.

Second shop lifts it on hoist and brings it up to 70 mph and notices that the rear transmission mount is broken as well as the Dynamic Damper (bolted to side of transfer case heavy rubber thing). I fix those and hop on freeway and problem still there.

Third Shop, Manny's Transmission in North Hollywood, bring it in to check the wheel bearings and explain the problem and Armando the owner says "stop talking just tell me the symptom" I tell him horrid noise and vibration at 70mph and higher -- he says "Go home - I'll call you when it's fixed."

A couple of hours later it's fixed! Wasn't the wheel bearings either.

It was a rear driveshaft front yoke with worn splines allowing driveshaft to flex at high speeds along with a super-worn super-non-lubed u-joint. I take it on the freeway and it purrs like a kitten! Yay!!!

I'm posting this because everywhere I searched for a solution to a 70mph hum vibration for a 3rd Gen 4Runner there's never a solution -- I only found guesses. Really expensive guesses.

So, at least in this case, I found the solution and it's way cheaper than wheel bearings and rebuilding differentials etc...

Start at a great transmission shop and hopefully save some bucks.

Thanks and good luck.

Joseph

Interesting, what companion flange yoke did he replace it with, Toyota quoted me $396 for #33309-35091..., tempted to try one off my other parts 4Runner but it’s probably a ball of rust or no better.

It was a used Toyota OEM part (I double checked with him). He showed me the worn out part and you could see some of the splines were erased looking almost. 318,000 miles on the original part though -- not too shabby.

Here's a pic of the part after the fix -
https://i.postimg.cc/3J5qD0M0/IMG-2900.jpg

3330935091 Toyota FLANGE SUB-ASSY, OUTPUT SHAFT COMPANION, Price: 88.19$, Weight: 1.043kg - PartSouq Auto Parts Around the World

Thanks Jz. And I don't order things from across the world except for Japan if I can avoid it, have you ordered stuff from Dubai before.

Yeah on several occasions. Partsouq is good to go in my experience.