4th Gear 35mph vibration/quiet thumping sound from middle-rear of truck 6 speed trans

LMAO ok ok ok lol, and just for the record my girlfriend entirely agrees with you lmao xP

 

Smart gal you have....

My name is Doug & I approve his post....

 

Haha you are correct sir lolol

 

Bump - Any update on this, or was it chalked off as normal RPM/gearing? I dunno that I'm 100% convinced as I just started experiencing this for the first ever time yesterday. And ironically enough it's on the heels of my first long road trip (several hundred miles to Jersey & back) for the 4th of July weekend.

Basically as OP described, its a faint vibe/shudder I can feel through the gas pedal in 4th @ around 35mph ("whoooomp.......whoooomp.......whoooomp......."). You can hear it as well, but it's very faint so AC off, radio off & windows up. I have a pretty similar rig setup and circumstances to the OP. Gonna inspect the U-joints and carrier bearing tonight. If they appear good, I'm probably gonna take it into the dealer since I'm only at 8K miles and can replicate it.

 

Okay, after hours and hours and hours of research I think I have this figured out. (Time will tell, but my eyes are literally burning from reading several hundred articles, posts, and opinions on this issue.)

I'm posting this for those like me who experience the notorious vibe issue in similar circumstances and resort to research finding this thread in the first hour of 10+ hours of research. Hopefully this will save you the additional 9+ hours of research I've invested sifting through the info below, and helps you correct the issue most expeditiously.

To further prove that OP is not "anal" and nor am I, I brought my rig to 35mph in 4th gear thus producing the "growl" and vibe replicating this issue today. I then threw it into 4WD - the growl and vibe instantly went away and stayed away until I disengaged 4WD. So it's not the drive-shaft, carrier bearing (drop), axle shims, front diff drop, tires, tire pressure, alignment, aliens, fairy's, Captain Kangaroo, etc. Feel free to read up on this below if you're not convinced.

"OFFICIAL 2nd gen 4x4 front differential bearing vibration thread" - A lengthy but good read albeit 90 pages. Focus on the latter pages/posts for dialing into the solution. This thread was also referenced by other threads for this issue on toyotanation.com
http://www.tacomaworld.com/forum/2n...nt-differential-bearing-vibration-thread.html

"front end growling noise" - Good thread & good info, last page dials in on the fix most frequently reported as being sucessful.
http://www.tacomaworld.com/forum/2nd-gen-tacomas/56236-front-end-growling-noise-8.html

toyotanation.com post on this, also very lengthy that contains a lot of good info and the most popular fix.
http://www.toyotanation.com/forum/6...220615-help-identifying-noise-feeling-40.html

And the fix is (drum-roll)......... Replacing the stock needle bearing with the ECGS Clamshell CV Axle Bushing
http://eastcoastgearsupply.com/i-8536125-toyota-8-clamshell-bushing.html

I'll update this thread after I install this on the results.

 

It's a good idea to replace that bearing anyway. When it fails, it takes out the front diff.
I replaced mine. The bearing itself is easy to replace. Getting to it is the harder part.