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Discussion Starter · #1 ·
Hi. I have parked my 2004 MDX at my Dad's for the past two weeks. He took it out a couple of days ago and noticed two things:

1. When he brakes there is a thumping sound which you can hear from inside the car and feel somewhat at moderate speeds. The thumping always starts when the brakes are applied and slows with speed and presumably the rotation of the tires. Under 10km you dont feel or hear it. I rolled down all the windows while driving at moderate speeds and can barely hear thumping from the outside. I had my brakes and rotors replaced in early March and driven the car quite a bit but never had an issue. No lights on the dash. No warnings. Tire pressures are all ok and tires are brand new from January. Sounds like the sound coming from the back

2. The shifter is physically very stiff to shift and gets worse the lower gear you go. From park to R is ok and to N is ok. But there is physical resistance going to D5 and it gets worse going to lower gear. I have apply sigificant muscle to put it to gear 1 or 2. The car functions fine transmission wise and shifts smoothly. It is the physical shifter that is very stiff

I plan to bring it to my mechanic. Any ideas in the meantime?


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If you had slotted rotors installed, it's just what they do... my MDX's previous owner put a full set of slotted and drilled rotors on. I guess that might make sense on a performance car, particularly if it was going to be driven hard or used for track racing. I think it's a little silly on an SUV, even one that's got reasonably good handling (for an SUV, that is...).

One thing that can cause the kind of issues you're hearing is keeping the brakes applied after a long, hard stop (like doing a panic stop from 70mph to zero). This can "cook" the pads into the rotors, leaving that section of the rotor with slightly different metallurgy than the rest of the disc, which feels like (and is often misdiagnosed as...) a warped rotor.

On the shifter, I have to believe that cleaning and lubing the shift cable will fix the problem. You really don't want to damage the cable by forcing anything TOO hard.
 

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Discussion Starter · #3 ·
If you had slotted rotors installed, it's just what they do... my MDX's previous owner put a full set of slotted and drilled rotors on. I guess that might make sense on a performance car, particularly if it was going to be driven hard or used for track racing. I think it's a little silly on an SUV, even one that's got reasonably good handling (for an SUV, that is...).

One thing that can cause the kind of issues you're hearing is keeping the brakes applied after a long, hard stop (like doing a panic stop from 70mph to zero). This can "cook" the pads into the rotors, leaving that section of the rotor with slightly different metallurgy than the rest of the disc, which feels like (and is often misdiagnosed as...) a warped rotor.

On the shifter, I have to believe that cleaning and lubing the shift cable will fix the problem. You really don't want to damage the cable by forcing anything TOO hard.
Thanks for the feedback. They are not slotted rotors, so can't be that.

My Dad is also a senior citizen so no way he would drive crazy like hard stopping. The guy barely goes of 40KM/hour ANYWHERE. Then again, if he had to hard stop in my car, I am not sure he would tell me. But...I doubt he hard stops since he doesn't hard go...:smile2:

As for the lubing shift cable - good to know and I will make sure I don't force the shift anymore...to D5 it is OK but a bit stiff but I don't use the lower gears anyway but I will have my mechanic look at it.
 

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One thing that can cause the kind of issues you're hearing is keeping the brakes applied after a long, hard stop (like doing a panic stop from 70mph to zero). This can "cook" the pads into the rotors, leaving that section of the rotor with slightly different metallurgy than the rest of the disc, which feels like (and is often misdiagnosed as...) a warped rotor.
This.
 

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Discussion Starter · #5 ·
So I brought it to my mechanic and he thought he was the rotors so he replaced the rotors but the same issue happened on the test drive after. So what it was is that the car was sitting for a week or two at my Dad's. Rust had developed and kind of caked on the brake pads. They sanded out the brake pads and the problem was solved. They also said if I had kept driving it regularly after, the thumping would go away as the rust will be smoothed out by use.

Regarding the shifting - they said it got better with use as well, which was true, so there is no lubing needed...so I am leaving that for now since it seems to shift into D5 OK now...
 
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