Not sure if I am correct on the symptoms or not.

But have been hearing a noise, a short duration steady tone when the car shifts from 3 - 4....but not all the time.

During my test drive for my brake switch repair fix, the tone appeared to me to be coming from the speaker????

So I turned the radio off and could not get the tone to repeat. Going to have wife try driving with radio off and listen for the tone next week.

Anyone have a comment or ever had something similar or am have I lost my mind after being upside down under the dash working on the brake switch?????

 

Having a hard time imagining it is actually related to the radio.

How would you describe the noise?

 

A single frequency tone, less than 0.5 seconds in duration, not very loud, just noticeable above all the other sounds going-on during normal acceleration.

Sounds seems like it is coming out of the speakers....but like I said have got to investigate this more. Has been happening for a good two months. We of course thought it was the transmission...and have been expecting it to get worse, but still the same.

Car is driven daily.


At a loss at this time.

 

There is a known issue where the transmission will make a sort of whoop noise when shifting. You might also describe it as a yelp or maybe a beep.

It can happen when shifting up or down. In my car it would happen under moderate to heavy acceleration, and especially noticeable when it downshifted.

The noise is harmless but there is a friction modifier that was later added to the ZF oil to address the sound. Has your transmission fluid ever been changed?

 

ccfulton: yes I have read about this and your description is pretty accurate and that is why I thought the noise was from the trans. Probably is...just really strange that yesterday is really appeared to be coming from the left front dash speaker....at the sametime, wife thought it came from behind her.

And to answer your question regarding whether the trans fluid was changed, yes it has as the pan was leaking so trans got oil replaced along with new filter/pan. That was a couple of years ago and this noise appeared 2-3 months ago.

Hopefully the dealership added the friction modifier when they did the work...hopefully.

As long as the noise is harmless then we can stop worrying about the trans locking-up and destroying the drivetrain.

Thanks

 

I think ZF stopped selling the friction modifier as a stand alone and it is just included in the Lifeguard fluid these days.

You actually have to go to a fair bit of trouble to fully drain the fluid out of the torque converter so a typical fluid and filter change really only replaces about half of the trans fluid.

My trans still will occasionally make the noise even after the fluid and filter was replaced. It doesn't happen often, so I haven't paid it much mind. Usually occurs on the 4-3 downshift under hard acceleration.

The 6HP transmission is pretty robust, all around. If the fluid level is correct and changed at sensible intervals then there shouldn't be much to worry about.