I’m new here, so thanks in advance for any assistance.
1. 2001 Mustang GT, convertible, 91K miles. Automatic transmission
2. Purchased 10/30/25, previous owner since 2003 was my wife’s grandmother. Of the 13 years I saw her drive it, she babied it.
3. Grandma passed away this summer unfortunately. I got the car as part of the estate sale for $3K.
4. The car had been sitting for ~2 1/2 years due to a coolant leak which turned out to be the plastic intake manifold coolant crossover assembly.
5. I put the Dorman replacement in (metal coolant crossover), also replaced thermostat and housing, radiator, reservoir and all hoses. Changed the oil with synthetic 5W20 (I believe. Whatever ford indicated in the latest TSB is what it got. 6 quarts of it for sure).
6. New plugs and coils, and all injectors removed and serviced before reinstalling.
7. Trans fluid looks pretty good. Still medium red, doesn’t smell burnt, no metal on the dipstick at least.
8. New tires to replace thermostat dry rotted ones it came with.
9. Full tank of fresh gas. It had less than 1/8 tank when it was parked.
10. Brake rotors are warped (all 4) and need to be replaced. Parts are in the rock auto cart now.
The car is for my oldest daughter, who is 14 now, and is bone stock except for the intake, which I’ve heard robs HP. I’m fine with that.
After several short trips to some surrounding towns for groceries etc, no more than 10 miles round trip, I’ve noticed a howl when accelerating, most noticeable from a stop. The convertible top makes it tough to hear it as well at speed but it seems to be pretty loud then.
There is also a pretty noticeable shake in the car around 30-45 mph during a shift. 1-2 seems butter smooth, 2-3 can be smooth but it seems to give that shake around that point. I haven’t noticed in 3-4 shifts. No major issues until today.
Today I drove my kids to school in the Mustang. Trip to the high school was good. I got on the highway to hit the elementary and middle schools, and I got a pretty decent shake from the steering wheel that got worse upon braking. Dropped kid 2 off at the elementary school and noticed a weird smell. Dropped kid 3 at the middle school and when I stopped I was overwhelmed with a scorched metal smell that went away as I drove it home, but as soon as I’d slow for a turn and when I parked in my garage it was overwhelming again. There seemed to be more noise but I couldn’t pin down where it was coming from.
Anyone have an idea of what could be wrong here? I’m leaning towards a stuck or rubbing brake for the smell but I’m certainly not positive about that. My second thought was the rear differential. The case is totally dry on the exterior but I don’t know the service history and I just realized that sitting for over 2 years may not have been good on the diff.
My last thought (the most dreaded one) is the transmission. I’m comfortable wrenching on the engine but I’m hopelessly out of depth with the trans. Rebuild quotes at the shops I called today ranged from $3200-$5000. That’s my worst case scenario, I know if it is the transmission it may not require a full rebuild.
Again, thanks to everyone for reading this. Here’s some pics of the car:
1. 2001 Mustang GT, convertible, 91K miles. Automatic transmission
2. Purchased 10/30/25, previous owner since 2003 was my wife’s grandmother. Of the 13 years I saw her drive it, she babied it.
3. Grandma passed away this summer unfortunately. I got the car as part of the estate sale for $3K.
4. The car had been sitting for ~2 1/2 years due to a coolant leak which turned out to be the plastic intake manifold coolant crossover assembly.
5. I put the Dorman replacement in (metal coolant crossover), also replaced thermostat and housing, radiator, reservoir and all hoses. Changed the oil with synthetic 5W20 (I believe. Whatever ford indicated in the latest TSB is what it got. 6 quarts of it for sure).
6. New plugs and coils, and all injectors removed and serviced before reinstalling.
7. Trans fluid looks pretty good. Still medium red, doesn’t smell burnt, no metal on the dipstick at least.
8. New tires to replace thermostat dry rotted ones it came with.
9. Full tank of fresh gas. It had less than 1/8 tank when it was parked.
10. Brake rotors are warped (all 4) and need to be replaced. Parts are in the rock auto cart now.
The car is for my oldest daughter, who is 14 now, and is bone stock except for the intake, which I’ve heard robs HP. I’m fine with that.
After several short trips to some surrounding towns for groceries etc, no more than 10 miles round trip, I’ve noticed a howl when accelerating, most noticeable from a stop. The convertible top makes it tough to hear it as well at speed but it seems to be pretty loud then.
There is also a pretty noticeable shake in the car around 30-45 mph during a shift. 1-2 seems butter smooth, 2-3 can be smooth but it seems to give that shake around that point. I haven’t noticed in 3-4 shifts. No major issues until today.
Today I drove my kids to school in the Mustang. Trip to the high school was good. I got on the highway to hit the elementary and middle schools, and I got a pretty decent shake from the steering wheel that got worse upon braking. Dropped kid 2 off at the elementary school and noticed a weird smell. Dropped kid 3 at the middle school and when I stopped I was overwhelmed with a scorched metal smell that went away as I drove it home, but as soon as I’d slow for a turn and when I parked in my garage it was overwhelming again. There seemed to be more noise but I couldn’t pin down where it was coming from.
Anyone have an idea of what could be wrong here? I’m leaning towards a stuck or rubbing brake for the smell but I’m certainly not positive about that. My second thought was the rear differential. The case is totally dry on the exterior but I don’t know the service history and I just realized that sitting for over 2 years may not have been good on the diff.
My last thought (the most dreaded one) is the transmission. I’m comfortable wrenching on the engine but I’m hopelessly out of depth with the trans. Rebuild quotes at the shops I called today ranged from $3200-$5000. That’s my worst case scenario, I know if it is the transmission it may not require a full rebuild.
Again, thanks to everyone for reading this. Here’s some pics of the car:
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