Some other examples of movies with altered sound effects:
The Godfather (I and II): The first two Godfather films have had several alterations in recent releases, such as ambient wind and birds.
H.B. Halicki’s entire filmography: The late director responsible for Gone in 60 Seconds, The Junkman, and Deadline Auto Theft, would have cried if he saw the numerous audio changes made to every single one of his movies. Not only have all the sound effects been altered, but Gone In 60 Seconds also has new, inferior music, along with several missing scenes (including most instances of profanity!). His widow is the one responsible for these changes, and she has outright refused all requests for an unaltered release.
Dirty Harry series: Among the most infamous stereo remixes in terms of changes made, all of the films in this series were butchered when released on DVD. Sadly, the Blu-Rays do not include their original soundtracks, so your best bet with these would be the Laserdiscs.
An American Werewolf in London: The film was remastered in stereo in 2001 for its 20th anniversary. Unfortunately, this meant that all of the sound effects were replaced, and the audio has also been slowed down for some strange reason. This is another film that didn’t get its original soundtrack on Blu-Ray, but its very first DVD release from 1997 does include it.
Smokey and the Bandit: Another film with altered sounds for its stereo remix, but luckily, the recent Blu-Ray features the mono.
1941: The “Director’s Cut” of this Spielberg bomb has a few slight sound additions.
Duel: Spielberg’s first film has also been ruined by its remastered version. I don’t know what sounds they added or changed, as I haven’t seen the movie. I’m guessing they changed the truck’s horn or something like that.
Halloween (1978): Apparently, modern thunder noises have been added. They also added tons of atmospheric insect sounds in the nighttime scenes. When Annie is inside of her car, you can still hear the insects even though she is supposed to be inside.
Mad Max: Severe alterations in the 5.1 mix, and there are even some original ones that have gone missing!
Psycho: Tons of added foley to scenes that are supposed to be silent. The worst thing is that this even includes the famous shower scene, where they added new water foley effects and squeaky faucets.
In The Heat of The Night: I have never seen this movie, but it apparently suffered a lot when remixed in stereo. This includes annoying ambience sounds (they added a distant train horn, for Christ’s sake!), and horribly reverbed audio (Ray Charles now sounds like he’s singing in a bathroom).
The Sound of Music: Not only are there modern thunder and rain sounds at one point, but some original sounds are absent!
Vertigo: One of the most infamous remixes of all time. The 5.0 remix on Blu-Ray removes most of the added foley (gunshots and footsteps), but there’s still some ambient wind sounds.
Rocky (the first film): Added foley and out-of-place reverb (why is there reverb in a parking lot?).
The French Connection: New car sounds and city ambience. Luckily, the Blu-Ray includes the mono track.
Evil Dead (the original): Several random sounds are missing in the stereo remix, possibly a side effect of the severe noise reduction applied. I’m not sure if the Blu-Ray features the mono or not.
The Conversation: Added foley, which has the result of making everything sound too busy. This one also has the mono track included on Blu-Ray.
Chinatown: Pretty much every time a gun is fired gets changed, as well as every scene of Jack Nicholson in a car. Another one where they have the mono included on Blu-Ray.
Butch Cassidy and the Sundance Kid: Another awful mess of added foley and insect noises. Even when the characters are inside with closed windows, you can still hear the insects! Horse hoof noises are also replaced, as well as all the explosions. The mono is featured on this Blu-Ray, too, but only on the American release.
Barry Lyndon: More altered explosion sounds.
My Favorite Brunette: According to an irate Amazon customer, the Blu-Ray released by Kino has added modern foley effects such as doors opening and paper crinkling.
Mobile Suit Gundam 0083: Stardust Memory: This anime classic received a 5.0 remix with different sound effects that are totally out of place for something that was originally released in the 80s.
Fox scanned the original 6-track mix for the Blu-ray of Sound of Music so it’s possible you’re referring to the DVD. For Duel basically almost every crash sound, engine, and other ambiance were replaced in the 5.1 remix but the Blu-ray includes the original mono as well. The Blu-ray for Vertigo includes the original mono as a second option. The Criterion release of In the Heat of the Night includes the original mono as the only audio option. The Blu-ray for Psycho includes the original mono as a second option. For Halloween sadly only the Shout! Factory blu-ray set includes the original unaltered mono. Rocky has the original mono as a second option on both of its Blu-ray incarnations. Both Godfather 1 and 2 include the original mono on their Blu-rays as a second option. The Criterion release of Barry Lyndon has the original mono.
Out of all the mentions here I’d say the three worst were Dirty Harry, American Werewolf in London (by the way the mix wasn’t slowed down, it was just pitched down), and Smokey and the Bandit.