Serial Number clarification

[EMTJEEP]

I was told a while ago that I have a TRS outdrive based off the pictures of the drive. But when I go to look up parts for it i get Mercruiser II TR setup. The serial number that is on the drive is 4545516 which falls in the II TR range while the TRS serial number range begins at 479**** and up. Am I reading this correctly? If it helps the serial number on the motor is 4499399. Which one do i have for sure?

 

[Fun Times]

While the serial numbers don't come up in the Mercruiser computer system do to the age, looking at a service manual index is also showing you should have a TR drive.

Transom Assembly and Stern Drive Units

MC 120/140 - serial numbers 3780850 to 4893634
MC 165 - serial numbers 3780850 to 4890459
MC 470 - serial numbers 4893834 and below
MC 888 - serial numbers 3784375 and above
MC 225 S - all models
MC 233 - all models
MC 898/228 - serial numbers 4898729 and below
MC 250 - all models
MC TR - serial numbers 3787240 to 5009866
MC TRS - serial numbers 4895289 and above
MC Jet Drive - all models.

Knowing the gear ratio might help determine what drive you have. Also what engine model/size do you have?

If you click on all three of the links to where they open for part listings, you'll see the gear ratios at the top. An example: II TR STERN DRIVE (2.00 RATIO)
http://www.mercruiserparts.com/selectModels3.asp?type_id=DRT