I am in the market for a new project car and daily driver. I found a 2005 mustang GT with 104k miles for a good price. Super clean. Asking $6200 firm. Generally speaking the 4.6 3v engine is bulletproof and as long as you don’t overheat it and keep fresh oil in it, they can easily last to 300k+ miles. The only thing I’m concerned about is the automatic transmission. Specifically it is a 5r55s. These auto transmissions were in the 05-09 mustang v6s and GT’s as well as early 2000s Ford Explorers and Mercury Mountaineers as well. Some of these cars I’ve seen ads for with these transmissions have very high mileage like 200-250k but I’ve also read about quite a few people online having theirs go out at 100-150k or sometimes even less.
The owner I’m buying the 2005 GT is the original owner and the only thing he’s replaced other than essential maintenance (like tires, brakes, oil changes) is the coil packs due to a misfire. Everything else is original. He says he’s never had any issues with the transmission. I know transmission life comes down to maintenance, how the cars been driven and luck of the draw but…My question is; if I change the transmission fluid and filter as soon as I buy the car do you think I’ll be ok? Or is one of these 5r55s tranny’s a ticking time bomb with 104k on it when it’s never been serviced? The car is 100% stock with no aftermarket mods which is somewhat encouraging because it likely hasn’t been raced or beat on too much. What do you guys think about this? And the car in general for the price I’m getting it at? Anyone have experience with owning or working on vehicles that use this 5r55s auto trans? If so how many miles has it lasted you/the owner? The bad things I’ve read about this auto trans is the only thing that’s preventing me from pulling the trigger on this car. And before anyone asks…I commute to work and drive in traffic a lot so manual is not an option for me.