The mt 37 is the direct drive, but you can get kits for the gear reduction starter also. There seems to be 2 or three styles of the 37mt. You probably better have it off before you order anything. I had one of these starters go bad because the armature was shorting on the mounting bolts as it turned. Then had a second one go bad, it would just grind. When I took the grinding one apart the lever the solenoid uses to engage the starter to the flex plate was broke and the drive gear was damaged The mounting bolts were insulated at the same spot where the armature was arcing on my other starter. I made one out of the 2. I ordered a new flex plate before I took things apart thinking that was my problem but I was happy it was only the starter, but I also have a flex plate, I hope I will never need. So don't make the mistakes I did. Take it apart and inspect everything first. I ordered the parts first thinking that the parts will be here when I have the time for the job, it ended up costing me extra.
Greg