Two Issues: Transmission and Brakes [Archive] - Forum


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07-02-2009, 08:13 PM
The warranty on my 2004 Grand Am GT is nearly up (about two weeks from now), so I plan on putting it in to a dealership for a top to bottom check for any warranty applicable repairs. Before I put it in, there are two issues I'm hoping to get some feedback on.

*In advance: please forgive my less than technical descriptions. I'm fairly competent mechanically, but like most (I think!) don't do an exceptional job of describing problems in technical terms.*

Issue 1: Transmission "clunk"

Occassionally when I started the car, there will be a loud clunk and the car will shudder slightly. The car is still in park at this point. The violence of the shudder varies (depending on who knows what) but I've noticed that it is most pronounced after the car has been sitting overnight (about 13 hours idle). The clunk is not noticeable when I start the car when leaving work (about 8.5 hours idle). I don't notice any issues when shifting from park to other gears and there are no issues with shifts while driving. There are also no warning lights on to indicate any failure.

From the searches I've done I have a feeling this may be a failed transmission mount, but from what I've found people typically mention a host of other symptoms that I don't seem to have.

Issue 2: Brake "Pulsing"

When braking I've noticed that the car has a shudder coming from the rear, or at least it feels this way. The best way to describe it is that if feels like the brakes are only grabbing at certain points in the wheel's rotation, or that you are pumping the brakes. My reasoning behind this is that the amount of shudder varies depending on speed: more pronounced at higher speed, less pronounced at lower speed. It also feels like it is only coming from one of the rear wheels, although I'm not sure which one. There are no ABS lights on or other warning lights to help guide me to a resolution.

The front rotors were milled a few months ago due to rust build up but no work has been done on the rears. I have a feeling this is a warped brake rotor, although the searches I've done make me learn towards the possibility of an speed sensor which is apparently location in the hubs (I'm open to correction on this).

Please let me know if additional information is needed regarding the problems and I'll try to expand on what I've already listed. For the record the car is at about 66000 kilometers.

I have a feeling that General Motors will say there's nothing wrong or that they can't diagnose anything without a computer code to guide them. They've used that excuse previously, and it doesn't instill much confidence in today's mechanics if the computer is the only diagnostic tool available (eyes and ears don't work anymore I suppose).

Any thoughts or recommendations you have are welcomed, appreciated, and thanked in advance.

07-03-2009, 03:22 AM
The pulsing coming from the rear is warped rotors. They hopefully will only need to be turned and everything would be good. Worst case senario is you would need new rotors.

As for the tranny issue I have no clue. Hopefully someone can come up with and answer for you or GM can figure it out without trying to screw you. Good luck.