I've got an 08' GXP that is making a tapping/ticking noise coming from the DOD lifter engagement. If I drop it into tapshift mode and put it in 3rd gear at low speeds it's extremely audible with the windows down. I noticed it driving through the downtown area where I live, I could hear the echo off of the buildings. The thing of it is, I just had all 16 lifters replaced in this car as well as a brand new transmission. The noise was there before the lifter replacement and it's still there now. I took it back to Pontiac and they told me it's "normal" DOD engagement and the car is functioning as it should. This makes no sense to me at all, there is no way they designed that DOD system to be THAT audible. Second, of what I know about DOD it should NOT be engaging at low speed like that. Isn't there an overdrive point where it should engage? 45 ish?

Any thoughts would be appreciated.

 

If your in 3rd ive had it come on as low as 17mph. And mine doen not make any noise when on

 

Hmm ..when i had DoD on i never saw it come on or stay on below 20..never had an audible noise coming from the engine from DoD from what i remember..

 

Thanks for the input, yeah it will come on as quick as I can get it into 3rd gear, which in tapshift is like 12-15 mph? Not sure what the lower limit is. If it's kicking in too early wouldn't that be an ECM/TCM problem? Not really too familiar with the system. Its definitely audible and doesn't go away at any point. I'm guessing the noise would be there at higher speeds too, just can't test it because of the air noise with the windows down.

 

my trans shifts to 3rd around 22mph, DOD comes on almost immediately if not on the throttle much, and I dont have a noise in my engine associated with DOD

 

Maybe its a bad DOD solenoid. I know fuel injectors can sometimes be loud.

 

Nevermind.....

 

There are complaints of a ticking/ rattle sound caused by the timing chain when 4 cyl. mode engages. There is a TSB on it(which I have a copy of but not on me now). It sates that the sound is considered normal. Just a thought.

The dealer gave me the copy of the TSB when I complained of a grinding noise and shudder in my trans. They handed me the TSB and said this is the noise I'm hearing, which is total BS because it only makes the noise when I'm in the throttle so 4 cyl. mode should not be engaging and I'm hearing grinding, not ticks and rattles. I told them the only rattle I heard when the tech and I went for a ride, was the tech's brain rolling around in his head.