An Issue On The Ford Mustang's 10-Speed Automatic May, Actually, Turn Into A Performance Benefit

While I mostly write about Asian cars, my true passion is performance cars. Amidst the occasional Porsche articles, I am searching for valuable information on all of our favorite sports cars. The iconic Ford Mustang GT is among those, and there is a lot to be said about it. Not to mention the Mustang Mach-E GT, which I recently revisited. While scouting for developments on a supposed hybrid Mustang for the future, I stumbled upon a post on the Mustang7g forum about a weird transmission whine. One particular owner seems particularly worried about why his Ford Mustang GT sounds like it has a supercharger (it doesn't). Here's what he says: 

Miikepk says: “I just bought a 2025 Mustang GT. It's automatic. I have read a little online that this whine noise is normal. Just wanted to post mine to see if it is. It does get louder when I rev. Sometimes feels a little embarrassing with how loud it can get lol. I placed my phone under my car to hear the noise louder as well. It does get a little loud I've noticed. I noticed it when I only had 40 miles on it. Currently, I'm at 180 miles.” 

The 10R80 automatic has a bunch of weird quirks, owners are complaining from. I found a thread specifically about this transmission's quirks. Some of the things owners complain about are a noticeable lag between throttle input and downshifting and unexpected secondary downshifting while accelerating from 55 mph or more.

Another despised feature of the 10R80 is the torque-based shifting strategy, which checks ‘torque plausibility” first, before deciding if it needs to downshift. Cars like the 2021 Mustang Mach 1 have this feature disabled from the factory, but it can be done on other cars featuring the same transmission. 

It seems most owners don't yet know about this feature of the 10R80 automatic 

One forum member explained the whining noise that the Mustang's 10-speed automatic makes, and it's not a problem with the transmission. In fact, it benefits performance. 

MAT1955 says: “The noise is caused by straight cut gears. There is a TSB on it, and Ford says no worries. The same transmission is in GMs (joint development project) GM put some sound-absorbing material on/in theirs but GM owners express concerns that it allows the transmission to heat up fast. I'd rather have the whine.” 

Another member, Gregs24, says: “Is it not the straight cut gears for the internal oil pump, not the gears themselves?” 

MAT1955 adds: “@Gregs24... You are correct. They are HD straight-cut gears for the oil pump as they are more robust. As pertaining to other comments on this thread, IMO - the 10R80 is an amazing transmission. IF, and I say IF, owners want to shift from first to second or second to third in excess of 7,000 RPM with an AT they are asking for a world of trouble. If someone wants to use their "stock" GT like that, they should take it to RSA (Race Solutions America) and have them build a Mac Daddy 1500 AT that will allow for ridiculously high shift points. As for the whine, Ford says it's perfectly fine!” 

The number of road-going cars that come out with straight-cut gears from the factory is extremely low. The old 6R80 found on early S550 Mustangs never had straight-cut gears, so some confusion is understandable for those transitioning from the 6R80 to the 10R80.  

That said, there are obvious advantages to straight-cut gears: 

1. Low friction 

2. Reduced heat generation 

3. Simple design 

4. Better power-transfer efficiency 

5. No axial trust  

In layman's terms, straight-cut gears mean less powertrain loss, greater capacity for horsepower and torque, and ease of manufacturing compared to traditional helical gears, found in most cars. The only real disadvantage of straight-cut gears is the whining noise they make. If you want a proper example of that, you only need to look at any factory or professionally-built race car. 

If you have any valuable input or experience with similar worries, feel free to drop a comment below.

Dimitar Angelov's automotive interests made him an expert in a wide variety of vehicles. Japanese brands like Toyota are closest to his heart, although performance cars in general are his favorite segment, which is why he is constantly on the lookout for the best deals on the market. Dimitar Angelov's car passion and knack for the written word led him to complete a Master of Arts in Media and Communications, and classic car restoration. Dim is happy to get behind the wheel of any car and share his impressions. You can follow Dimitar on X, Linked-in, Instagram, and Facebook.

Image source: 2025 Ford Mustang 60 Years