Driveline clunk and rear wheel lock up??

Thanks in advance if anyone can shine a little light on this. I'm stumped.

2013 DCSB 4WD Auto. 85k miles, stock truck, no mods.

I have been dealing with what I thought was a VSC/ABS issue after installing larger tires. (255/75R17 Duratracs on FJ steelies).

The day after the tires went on I started getting intermittent drive train "clunks" sometimes while braking sometimes while accelerating, sometimes turning, sometimes straight..could go for days with out anything, then bang, loud clunk in the drivetrain. On a few occasions this occurred at low speed and caused the left rear wheel to actually lock up for 5 feet so then release. Scared the shit out of me.

I found the thread here about similar sounding problems after installing larger tires and followed the great write up by CROM about resetting the VSC...I performed that successfully ( got the flashy lights slow at first, then faster after reset) but it has not fixed the problem. I've done the VSC reset 7 or 8 times always on the most level ground I can find, the thing is still doing it.

I also confirmed today that it happens even when I've turned the Trac Control off.

I've cleaned and inspected the wheel speed sensor QDs.

I drained the Rear Dif fluid today and it was super clean, no metal at all on the mag plug.

I downloaded OBD Fusion and the Tacoma package and it's not showing any codes.

No off-roading, all the fluids have been changed on schedule or sooner. Had it since new, never a problem.

Today I swapped back on my OEM 16 rims with 245/75R16 Bridgestone Duellers, and it still was doing it. So I reset the VSC again. Still doing it.

I'm now leaning away from VSC/ABS issue to driveline but what? Transfer case?
4wd worked fine when I tested it the other day...no noises.
Transmission? Torque Convertor?

At my wits end...can anyone suggest a next place to look?

Thanks so much guys...this forum has been a godsend over the years. I'm usually just a lurker, but figured I'd send off a flare on this one and see if anyone's had a similar issue.

 

Have you checked the rear drum brakes? Does the parking brake work?

They might be way out of adjustment or could be broken hardware

 

I did not check the drums. Does the Parking brake stop both rear wheels or just one?

 

Both. And check the cables too. Have a helper push the parking brake and make sure the cable moves back and forth and isn't stuck

 

I agree with this guy.

I remember someone on here having a similar issue.
He pulled the drum and found a broken spring.

 

Parking brake seems to work great. I'll look at the cables tomorrow.
It's hard to describe this clunk...things are so subjective...but if it's brake related it feels like it has to be an ABS problem because it's like a quick pulse, just a micro second, feel the jolt thru the frame then it's gone.

 

Ok well I know what I'm doing tomorrow then....thanks fellas.

 

You could pull the ABS fuse (30A) and kill the ABS system.
See if the problem continues.

And obviously, before some one freaks out, do so at your own risk.
Anytime you disable a safety feature, things can get dangerous.

Again, I’d start by pulling the drum first

 

If you have new tires, i presume you got an alignment with those new tires. Make sure that they torqued your alignment hardware )LCA bolts) properly.

 

I’d pull the drum off on the suspect side and see what the hardware looks like. I’m doubtful it’s an ABS issue and rather some piece of hardware intermittently locking up your wheel.

 

Bingo!
Looks like both the Shoe Hold Down Springs and their cups were unsecured...no signs of the pins.
I think it's time for a visit to the tire shop that also "inspected the brakes"