It is very close to a YM1602, almost identical behind the engine. The 1602 is a three cylinder, the JD is a two. They are not power-shift. Hope this helps.
My Mom and her husband have a 650. I believe it is a 2wd 14 hp and they used to have a JD mmm for it. It does not have powershift. I believe it was built early to mid 80's. Nice little tractor and there are a lot of similarities to my 1500D.