Auto transmission Clunk at red light with brake on

Often, when stopped at a red light in my 07 Tacoma TRD 2WD, the auto transmission has a noticeable clunk when the brakes are on and the truck is not moving. Sometimes I can also see and hear the engine rpm change. It seems like the transmission may be downshifting to 1st gear while stopped. I've never had a transmission do that after I stopped.

I've read the thread on axle wrap that sounds similar. But I don't think that is the problem because I'm not moving. One reply in that thread suggested that this might be a torque converter issue. Could this be my problem? If it is, does anyone know if it would be covered on the 60K driveline warranty (I have 56K on the truck now?

 

It's totally normal. Mine does it also.

It can be more 'pronounced' or 'noticable' if you stop quickly.
If you brake early and gradually come to a stop, the 'thump' isn't as noticable.
It can also be more pronounced & noticable if the A/C is on.

The transmission IS part of the drivetrain - so YES, it should be covered under 5 year (?)/60k warrantee.

I would recommend taking the truck in to the dealer and explain the problem to them. They'll probably tell you *it's normal* because it is - but ATLEAST request they check your transmission fluid and fluid level (since, these trucks don't have dipsticks )

 

Yep, just get used to keeping a firm foot on the brake at stops.

Mine only really does it with the AC on.

 

Thanks for the replies. It's a bit unnerving but I guess I'll get used to it.

 

yup mine to mostly when the ac is on

 

Same here.

 

Sorry to dig up an old thread, but mine is doing this too, only when the AC is on. I was considering taking it in to the dealer, but seems as though this is normal? Is there any long term issues, will this get worse? Do we have any solution to the problem? I guess I don't feel like spending the diagnosis fee for them to tell me its normal.

 

The A/C compressor cycles on and off as needed. When it cycles on, the idle speed is automatically increased at the same time. Pretty annoying, but normal. This also happens when you have heater in defrost setting.