[btanchors]

I have a 2006 Tundra Limited 4WD Double Cab. In the past, Engaging or disengaging 4WD was almost seamless - it was barely perceptible when engaging or disengaging 4WD.

But lately, I am consistently getting a pronounced "thud" sound when disengaging 4WD. It never happens when engaging, only when disengaging. Engaging is still barely perceptible.

I generally only activate or deactivate 4WD when moving about 35-40 mph, either when coasting, or under a very light load.

The 4WD system did get a pretty good workout this past winter season, as we had two large snows, and a couple smaller ones.

It seems to be otherwise operating properly, and consistently without any issues other than the "thud" sound on disengagment. Oil was changed not too long ago, and is at the proper level in both the transfer case and front differential. The draft shaft zerks have been consistently greased as well.

Does this sound indicate a problem developing? Do any of you hear or feel any sounds when disengaging 4WD?

 

[Thundra04struck]

I always got a sound/clunk getting OUT of 4WD, since day 1.

No sound going in, just getting out. Sometimes it is louder than other times but it is normal.

 

[DMZX]

Mine ('05 DC) will clunk a bit going in or out if there is any load on the drive train. So I got into the habit of engaging and disengaging on level ground with my foot off the gas for a few seconds. Doing that I can neither feel it or hear it.

 

[spleck]

I only hear any noise if I'm back on a better traction surface. Have you lubed the axle? What kind of mileage do you have on your transfer case and front diff oil?

 

[Johnny_5]

Mine ('05 DC) will clunk a bit going in or out if there is any load on the drive train. So I got into the habit of engaging and disengaging on level ground with my foot off the gas for a few seconds. Doing that I can neither feel it or hear it.

That's how I do it. No more clunks.

 

[btanchors]

Splec:

The truck has 63,000 miles on it. Lubricant used throughout the drivetrain (Rear and Front Diff, and transfer case) is Amsoil Severe Gear 75W-90. I just changed it and it made no difference.

Interestingly, just for grins, I tried slowing to a complete stop while in 4WD, and then pushing the button to disengage 4WD. The "clunk" sound still happens, even if the truck isn't moving, although it is a bit less strong.

Also, the drive shaft is lubricated myself every 10,000 miles, using Amsoil GHD grease.

 

[Johnny_5]

Even if you are stopped, it could be bound up a little. Try shifting it while coasting as DMZx suggested above.

 

[btanchors]

Johnny 5 (and others)

I have tried it under varying load conditions, including coasting, and as noted above, even at a dead stop. The "clunk" is pretty consistent. I don't understand what has changed, since it didn't do this in the first couple of years of owning this truck. Nor do I know what this might indicate. But at any rate, as far as I can tell, it operates normally otherwise. My only worry is whether it might indicate the <beginning> of something that might be failing or deteriorating. I do have a Toyota extended warranty out to 100K, so unless anyone has any other suggestions, I think I am going to live with it for awhile.

 

[Dinosaur]

I will get a clunk when there is "pressure" or "load" on the drive line from either turning or the motor pushing. I try to coast every time when shifting in or out of 4WD.

Do you get the clunk at 45 or 50 MPH?