borg warner t10 transmission

[Kristen]

Can a borg warner t10 transmission from a 1966 mustang be installed in 1956 Thunderbird without any major modifications?

[55blacktie]

Define "major modifications."

[Joe Johnston]

"back in the day.....!" the T10 was an easy and popular swap. That said, that was basically all that was available then. The T10 was available across many brands and engine sizes, so I am a bit concerned about the mounting bolt dimensions coming from a Mustang. It was popular because of the schrynos (SP) in first gear. Final drive still is the same at 1:1. So highway engine rpm will be the same.
Today a better choice to consider is one of the overdrive manuals, (Trimek 5 speed) and adapters are available. A local person had one installed along with a 4:11 rear end gear and loves it! It is a rocket off the line and fun to drive. He was not concerned about milage or highway crusing, but the combination of an overdrive manual and the 4:11 made very little difference of engine rpm at 70 mph.
Your car, your choices, your checkbook! Enjoy the ride!

[427John]

If your car is currently a T85 with OD or a long tailshaft T85 w/o OD a T10 from a 61 to 64 Galaxie will pretty much bolt in with the exception of the shifter and the clutch disc 61-62 used a 23 spline input shaft while the 63-64 went back to the 10 spline, depending on what shifter you use will determine how much floor hole modifications are necessary. The 66 Mustang T10 should bolt to your existing bellhousing but will be too short to reuse your existing drive shaft, it will use a different trans mount configuration and will also be in the wrong place, shifter mounting may or may not be in the right place, this can all be addressed but will need some fabrication to make it work.

[55blacktie]

My 1966 Mustang GT came equipped with a T10 transmission. The transmission needed a minimum of new synchros, and parts were hard to come by at the time. I also didn't care for the heavy cast iron. I cleaned up the T10 and sold it at a swap meet, and I didn't hesitate to disclose the need for at least a 3rd-gear synchro. I intended to replace the T10 with a Top loader, but I sold the car before reaching that point.

If you have a T85/w OD that's in good condition, I don't see that replacing it with a T10 is an improvement.