bearing or grinding noise at high speed deceleration

The 100K powertrain should still cover it. The dealership is trying to claim that the ARB locker has voided my warranty, but if you haven't done anything like that, then you should be good.

 

My 06 Reg Cab does the same thing on the highway. I have an idea that it may be the cat. converter has gone bad. Haven't had the time off work to check it out though.

 

my 09 had that same problem, not to be negative but the new rear end doesnt fix it i know this because when i traded it in for my 07 it was on its 3rd rear end. the new gears make it go away for a while but then it returns, in my case somewhat quickly. However, i found that putting synthetic gear lube in for the 30k fluid change made it go away for about 10k miles and when it returned, it was only noticable to only me, and was a much lower volume. I gave up on finding a real fix, but i hope this helps.

 

So I finally Killed the damn noise 9 months later!

It took 2 things
1) CV driveshaft
2) Angle differential to point up at transfer case

The retarded part is that I took it to a driveline specialist and they said it wasn't the shaft. After replacing my transfer case the noise persistedm and there were no options left so I started eliminating possible driveshaft issues. Here's a technical explanation of what's going on.

http://www.4xshaft.com/driveline101.html

 

FYI
mine does this and I don't have a "lift". What I do have is 29.5 inch tires rather than the 27 inch stock tires, so I guess that has a similar effect, just not sure exactly how much of a lift.

 

Mine started when I had no lift. I only have the TSB now.

 

didn't you put on some larger tires?

 

Yes, but I don't remember where along the way that noise started. Maybe it was after the tires.

 

I bought mine with the larger tires, so I can't say either.

 

mine makes this noise when gas tank is below 1/3. i have 2" lift. could it be the fact that the tank is plastic? gas tank may vibrate from proximity to driveline.

 

Less gas = Less Weight
Less weight = Less suspension sag
Less Suspension sag = higher driveline angle

 

Theres a good thread about this at ttora.. And alot guys have had success in eliminating this noise by removing the driveshaft, regreasing the slip yoke and installing the driveshaft backwards,so that the slip yoke is at the diff end like the older tacomas
heres the thread link http://www.tacomaterritory.com/forum/showthread.php?t=43824

I recently got this noise after installing the dakars on my reg cab and im gonna try this tomorrow night to see if it works

 

So I flipped my driveshaft around..I didnt grease the slip yok or the ujoints to get a good idea if the noise being gone was from the swap and not the greasing..
I've only just been able to get my truck up to highway speeds as i swapped in new diffs with 4:88 gears and ARBs
I really wasnt expecting much from this flip but the noise is actually gone altogether...I've only been up to 65 but the noise started usually around 50 or so and up..
I have axle shims that i ordered but am going to hold off on them and see if it comes back or not

Heres hoping

 

good to hear, keep us updated after your gears get broken in

 

could you take a pic of your driveshaft after you flipped it?

 

It sounds like the is driveline flawed, improperly phased U-joints and even excessive driveline angle. The thing is none will produce noise just vibration. If its noisy then check all U-joints and look for grease on the trunnions if they are sealed. If they are not sealed then grease the trunnions make sure grease purges from all 4 caps on the trunnion. If the noise continues check for play in the driveline you should not see any. My truck has a +1 wheel and a
+3.5 tire and over 67K no play in the drive line.

If the driveline shows excessive play either up and down or side to side (1/8" to a 1/4") then take it to the dealer.

 

Same exact thing happened to me after dakars were installed. converted to cv driveshaft and no more grinding noise when letting off the accelerator at any speed above 45 mph

 

Ok heres some pics as requested about the shaft flip..I have finally had my truck up to 75 and there is no noise at all any more.. I dont know what this flip does but it is working on my truck.. for now
The only downside I can see to this is the slip yoke boot is more exposed for possible damage.. Other then that there are no vides and all is running well... If it comes back i will probably start running a cv driveshaft as stated above

 

thx for the pics. i'm having a tough time getting the bolts to loosen.

 

i have a similar problem. The symptoms sound the same. This only happens when I brake real hard anywhere from between 40-75mph. I hear a loud clunk and somewhat a grinding noise from under me. This also doesn't happen all the time and 75% of the time if the road isnt smooth.