Check your U-Bolts!!!

That may not work as the spec for the U bolts on a 2nd gen is something absurd like 37 ft lbs. Mine were loosening up so I tightened them to 90 ft lbs which is the spec for that size hardened bolt. No more problem.
There are other threads about this on tacomaworld.

 

OMG is that where dealership mechanics come from?

 

https://www.tacomaworld.com/threads/check-your-u-bolts.397913/

Factory service manual specification for 3rd gen u-bolts is 52 ft lbs.

 

You may want a breaker bar too so you don't abuse your torque wrench.

I think I just lifted my truck by the differential pumpkin and loosened the 4 nuts and the bottom of the ubolts. Then just swap them out with the new ones. Once you get going its a piece of cake.

 

Gen 2 is "37" but it's widely thought of as a typo and most people go 73 .... 37 is pretty loose if you ask me ...

 

According to this excerpt from the service manual, it is 52 ft/lbs for the 2WD and 37 ft/lbs for the 4WD and Prerunner. I can't explain why the difference.

 

Well, considering that people are having issues with loosening U-bolts, I will stick to a much higher torque, especially when going aftermarket.

 

Too much torque could lead to either snapping the u bolt or crushing the axle tube. However I think anything under 75ft/lb's is safe. I'll likely just tighten mine to 60 and call it good. I'll be curious if it cuts down on the clanks.

 

Yes way too loose, that's why they keep loosening up and need to be checked after a mall cruising run with a lot of speed bumps.
The typo explaneation makes sense but I didn't know about it when I picked 90 ft lbs based on the size of the bolts.
Ninety ft lbs has caused no problems other than I don't have to check to see if they're loose (working on your truck helps you bond with it).
One could tighten them tight enough to damage or break the bolts which is why I checked the generic torque table.
There is no way you could distort the axle tube before the bolt broke. The rear axle is strong enough that you can jack up the truck by the pumpkin.

 

I had been driving mine for a year and put mine to 52 on Sunday (2 days ago) which is why I wrote the comment in the thread referenced by the OP. Considering a whole year of wear by torsion and perpendicular transmission forces from driving, shifting, and off-roading, I wonder if the 52 isn't quite tight enough anymore.

One thing I forgot to mention is that when you torque these 8 bolts, you should cross-stagger the torquing order to keep wear consistent.

Lastly, this whole ordeal is a major discovery by Toyota customers that will inform future engineering and is a good candidate for a case study in dynamics.

 

I can't explain it either... but I know without a doubt my truck drives better and makes considerably less noise with them torqued at 52 compared to whatever it was (WAY less than 52) from the factory.

 

SAME. My parts finally came in after 2 MONTHS of waiting. Will be going over their work as well.

 

https://www.suspensionspecialists.com/techinfo/Ubolt_Information.pdf

Good read from a quick google search.

Does anyone have the specific grade and thread of the OEM u bolts?

 

I just checked mine, all were tight. Build date 10/2017, 1,900 miles.

 

Just tightened mines down a few days ago here's my take on it after 100 miles. Measured them from the factory at 27 ft. lbs and torqued them to 52. So far this helped with the rear end clunking sound I was getting when feathering the throttle at low speeds, along with smoothing out acceleration. Before tightening I would describe low speed acceleration as throttle, rear end clunk, then acceleration in that order. It's still kinda there but it is less noticeable.

 

Tightened mine last night. They all needed about 1/4 turn to reach 60ft/lbs. no noticeable diffference while driving.

 

Checked mine today, they were a bit loose and also found this.

 

hope its just a brake cylinder, not the other axle seals

 

It's the axle most likely. Both sides and the diff cover leaking. And it whines.

 

wow was the differential overilled with gear oil, pretty tough to blow all them seals out