Noise during acceleration

L

Luis_fx35

Member
Location
Garland, TX USA
Hello to everyone. Looks like my 120k miles on my FX are starting to ask me for more parts that need to be replaced. It started to happen right after changing my rear brake pads (non-OEM bought from pepboys). I replaced the front brakes twice since 2007 when I got my FX, however I never replaced the rear ones until now, they had very little material left and I had to push the piston a lot for the new pads to fit properly. I hear this noise 85% of the time when I come to a stop or a red light and then I accelerate to rech 25-40 mph or when I leave the car parked for a while and then I go from the parking lot to an avenue and I exit the parking lot fast to reach 25-40 mph in the avenue. The noise is like metal on metal noise and I feel it right under the car, it is really hard to know if it is coming from the rear or the front. The first time I noticed this noise I thought it was my transmission because it only happened when I was accelerating from a stop; If I only press the gas just enough to get the car moving from a stop (like 20mph) I do not hear any noise. However IF I ACCELERATE QUICKLY from a stop or after exiting a parking, or entering to a higher speed road I hear it, once I reach 30mph or more I do not hear anything. Looks like the noise is happening during the transition from 2nd to 3rd or 1st to 2nd gear and once I reach speed the noise is gone. I thought the problem was my transmission and I went to the dealer and got the transmission and differential fluid changed. The noise is still there and I wonder if there are other fluids related to the tranny that need to be replaced, as u can see, I have a RWD fx and I thought thats all I needed to replace. On the other hand, seized calipers seem to be the other possible cause of the problem. I did a search and found some related topics and looks like this could be the problem. I hope it is just the calipers and not the tranny, everything was good after I changed the rear brake pads. I wonder if the calipers got used to the old pads which had very little braking material left and now that I got new ones they wont separate from the rotor until I reach speed. The noise is very loud and if I Accelerate fast in an alley or close to a wall the noise is terrifying once I reach speed is gone. My FX needs new shocks, struts, and new rotors too but I need this noise gone before I invest on the other important things that need to be replaced.

I hope this is not a repost and if someone can help me out with this noise that is driving me crazy. I was about to put my old pads back to see if the noise during acceleration disappears. Thanks


More Info:
Front wheel bearings replaced six months ago.
When I changed the rear brake pads I forgot to open the brake fluid reservoir and I just pushed the pistons with my c-clamp. If I go to the dealer to drain the brake fluid and put new fluid would this help my calipers adapt better to the new brake pads?
Hard to describe the noise, I hear it under the cabin like if the propeller shaft were louder when I step harder on the gas from a stop during 1st and 2nd gear then no noise until next stop. That's why I thought it could be the transmission, but then again I think the brakes have to be related, and all this noise right after changing rear brake pads, why? who knows
 
Last edited:
Can you describe the noise you hear? Wheel bearing can be a possible cause. Have any of them been replaced?
 
Grinding noises aren't good.

You say the noise goes away if you let off the accelerator at speed?
 
To me these sound like most probable causes:

1) Breaks (especially since it started right after you changed them)
2) Wheel bearings

May have to do some process of elimination.
 
la_fx35 said:
Can you describe the noise you hear? Wheel bearing can be a possible cause. Have any of them been replaced?
Click to expand...

Update Noise: Front wheel bearings replaced six months ago. Hard to describe the noise, I hear it under the cabin like if the propeller shaft were louder when I step harder on the gas from a stop during 1st and 2nd gear then no noise until next stop.

---------- Post Merged at 08:03 AM ---------- Previous Post was at 07:50 AM ----------

aiya said:
Grinding noises aren't good.

You say the noise goes away if you let off the accelerator at speed?
Click to expand...

It goes away after I reach speed like 20mph with or without releasing the gas pedal. like when the car needs all the power to move from a stop 1st or 2nd to 3rd gear. If I dont step hard on the pedal I dont hear noise only on quick acceleration or when you are approching a light and it turns yellow and you step on the gas to make it I hear this noise. and I have done this many times and never heard that noise before.
 
Last edited:
Recheck tranny fluid. Something might be wrong with the tranny. Check tranny and motor mounts. Also chek ur differential u joint
 
Dracula said:
Recheck tranny fluid. Something might be wrong with the tranny. Check tranny and motor mounts. Also chek ur differential u joint
Click to expand...

Oh I see, ... I did not think about the mounts, however I still think that it is really weird that it happened right after replacing the rear brake pads. I hope the dealer can tell me whats going on and not charge me $$$ just to diagnose. what are the symptoms of a near-to-break tranny?
 
my 03 does same thing. i believe its tranny/differential possibly transfer case. ever since my car was towed on 2 wheels (not flatbed), the AWD dash light intermittently displays upon start up. believe i need new transfer case but the noise that resonates from underneath cabin is heard when flooring or accelerating rapidly for about 2 seconds. i think its the fluid in differential/tranny
 
You must log in or register to reply here.
Back
Top