: Question regarding slight motor mount/tranny thump

07-01-11, 03:22 PM
I have a 2005 Deville DTS bought a little over a year ago. Not long after I bought it I noticed a slight thump about 60% of the time when it shifts into second or most of the time when the car is floored while doing 20-30. It's not a huge deal but it's a little annoying and it seems to me the motor mount(s) would be the culprit. I just replaced my front rotors and pads today and coincidentally I noticed two of the motor mounts are right in the wheel well behind the brakes. Couldn't see completely around the mount but they both looked ok. So my question is where is the other mount (didn't have much time to poke around for it today) and does the thump seem like it would be a mount related issue?

My other question is....what would cause the tranny fluid life index to go down? I know under normal operation it's supposed to stay at 100-99%. I bought the car with (if I remember correctly) 77% life. And after a year it's now at 73%. Could this be a problem and would this have anything to do with the thumping I feel? Or is the tranny fluid leaking or something? Thanks for answers. :)

Other than this the car is in very very good shape and the Northstar is like new.

johnny kannapo
07-01-11, 03:36 PM
The trans fluid life can go down to "0" before it needs attention & there is probably a pre-fluid service message that will show up with ample time before that.
The thump is most likely a mount that is torn.
If one mount goes it will lead other mount trouble as well as wires & hoses moving around more than they were intended to.

07-01-11, 04:04 PM
Thanks for the info on the tranny fluid.

I actually have a new problem that I'll just post here rather than make a new topic somewhere... So as I mentioned above I just replaced the rotors and brake pads today because I've been having a vibration in the pedal when braking. Started about 2 months ago and got worse so I thought the rotors needed replacing even though they weren't in bad shape. Well the replacement did nothing and I still have a very noticable shake/vibration in the pedal and steering wheel when braking even at slow speeds. Any idea what this is?

Thanks guys.