single rear end knock when first rolling

I've noticed a single knock that comes from the rear of my truck everytime I shift from reverse to drive (as in backing out of the driveway then shifting into drive to move ahead) After moving forward about 5-7 feet, I get a single little pop. The truck is only a week old, 2012 TRD OFF Road 4WD AUTOMATIC DOUBLE CAB. I will be back at the dealer in a few days and will be bringing this to their attention but, I would like to know if anyone has experianced this and has any info that would help. Thanks

 

Yes, I have EXACTLY what you describe. I've got an SR5 4WD auto DCSB that's about two weeks old and won't be back at the dealer for a month or so. Please post back what your dealer has to say about this.

 

Could be brake click or axle wrap. Does it happen when you press the brake, or only after you roll forward a bit? Do you ever get the noise upon coming to a stop, such as at a red light in around town traffic?

 

Only after rolling forward a bit and only after backing up. I don’t think this happens when backing out of a parking spot but I haven’t really had the chance to play with it yet. I back up 40 - 50 feet out of the garage and out into the street. Put it in drive and move forward a few feet and you can just hear the pop as the OP described.

No.

 

Here's a crazy suggestion.... could it be gas "slapping" in the tank?

 

That's brake clack. It's normal and not hurting anything. The brake pads are shifting in the calipers when the direction of the vehicle changes and you brake. It's coming from the front end.

If the OP has the same symptoms, then that's what he has too.

 

If the correct diagnosis is brake slap, and this is normal, then why would I hear it on this new truck but have never heard it on the other two tacomas I have owned? It really does sound like its comming from the rear. Don't mean to sound sarcastic, I just wondered why. Is this something common to the newer tacomas? Thanks for the reply.

 

^^ X2 what jandrews said..... completly normal.

 

It's very common to the 2gen Tacomas. As far as I know, the previous generations never had the issue (different caliper design).

IF (that is the key word) that is the correct diagnosis, it's nothing to worry about.

Go outside on quiet day and go backward and forward in your truck a few times with the windows down and your head sticking out. You'll likely then be able to tell if it's coming from the front or rear.

If it is in fact coming from the rear, that opens a whole new can of worms.

 

It does it on my 08 Taco also, slack in the brake shoes.

 

Well I guess that’s good news but there’s just something about “shifting brake pads” and “normal” being used in the same sentence that fails to impart that warm fuzzy feeling of confidence in a brand new $30,000.00 truck. Oh well, thanks for the info.