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Discussion Starter · #1 ·
Alright guys, I’ve been trying to find the source of a grinding noise for a while with no luck. I’ve searched the forums and haven’t found anyone else with this exact issue. It’s a 2007 Charger R/T, 5.7L, AWD, NAG1, 170k miles on her.

This is what I got, under a load such as hard acceleration from a stop, there is a metal on metal grinding noise, from inside the car it sounds like it’s coming from somewhere near the front of the tranny. I can reproduce the sound if I hold the brake hard and hit the gas like I’m trying to do a brake stand but without letting the wheels spin, just put a heavy load on the driveline. This makes me think it’s something in the tranny because at that point nothing is spinning except the motor and the torque converter.

I originally thought it was front CV shafts, it’s an AWD, but after replacing both cv shafts and both wheel bearings l, the grind is still there.
Today I did a tranny fluid and filter change. There were no metal pieces or shavings in the pan. The magnet it the pan had a small amount of sludge on it, almost like thick grease, but it was a very small amount. After the new filter and fresh tranny fluid I went for a ride.

The noise is still there.

Again, it’s only under a hard load like accelerating up hill or hammering it from a stop. Otherwise there is no noise, it shifts completely fine with no hesitation or slipping in any gears. Anyone in here ever have a similar issue??
 

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If the rear drive shaft center bearing is OK , its probably in that tiny T case , drain the fluid in it and inspect.The AWD is very difficult to chase down noises because of all the moving parts and the noises will telescope though out the car . Also check for rocks stuck in the trans cross member and exhaust system grounding to body/frame . I haven't seen any grinding issues with the NAG transmissions , usually its the AWD T case .
 

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Check your motor and transmission mounts. Under load, I was getting some kind of fluttering/grinding sound that seemed to be coming from the front left wheel well. Turned out both motor mounts were broken and the left motor mount had completely separated. Sound went away after both motor mounts were replaced.
 

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Check your motor and transmission mounts. Under load, I was getting some kind of fluttering/grinding sound that seemed to be coming from the front left wheel well. Turned out both motor mounts were broken and the left motor mount had completely separated. Sound went away after both motor mounts were replaced.
Very good idea! my oil pan was occasionally touching the steering rack and making a weird buzz in the floor.
I found that motor mount bolts on one side were broken and engine was leaning to one side.
Of course didn't notice this before i bought the car.
 

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Discussion Starter · #7 ·
*UPDATE*
It was in fact the motor mounts, I couldn’t see that they were broken when I replaced the front axles, they looked intact to me but I had the hood open the other day and put a load on the driveline, watched the drivers side of the motor lift right up a few inches.
Thanks for the ideas guys!
 
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