Take a look at this 97 GS tranny tag located on the back of the housing (same location for 440-T4). If you notice the code 7HKB - the 7 stands for the year (1997 in this case). Your tag should also denote the year. The three letter combo identifies the ratio.
RPO Codes:
F79: 2.97
GX3: 3.33
Transmission Tag Boadcast Codes and Ratio Identification:
Obviously, this list is very incomplete. The best source of these codes is from GM service manuals for their respective years. If you have a manual with codes, please add them here. Finding these codes is very difficult and to my knowledge this is the most complete list on the internet thus far.
1987:
2.84 Gear Ratio:
2.97 Gear Ratio: 7FJH
3.06 Gear Ratio:
3.33 Gear Ratio: 7ACH, 7CAH
1988:
2.84 Gear Ratio:
2.97 Gear Ratio: 8BTH
3.06 Gear Ratio:
3.33 Gear Ratio: 8AJH, 8CDH, 8CFH, 8CMH, 8CRH, 8CTH, 8CWH, 8CXH
1989:
2.84 Gear Ratio: 9BHH, 9WRH, 9BPH,
2.97 Gear Ratio: 9BWH, 9WUH, 9AJH,
3.06 Gear Ratio: 9BAH, 9BDH, 9BFH, 9BMH, 9BKH
3.33 Gear Ratio: 9PAH, 9PBH, 9BWH, 9AAH, 9ABH, 9AFH, 9ANH, 9ATH, 9BJH, 9CDH, 9CLH, 9CZH, 9CPH, 9CYH, 9PAH, 9VXH, 9YAH, 9YBH, 9YFH, 9YJH
1990:
2.84 Gear Ratio:
2.97 Gear Ratio:
3.06 Gear Ratio:
3.33 Gear Ratio: 0AJH, 0CHH, 0CJH, 0KHH, 0LAH, 0LMH, 0LNH, 0PAH, 0WXH, 0YDH, 0YHH, 0YKH, 0YLH, 0YRH, 0YSH, 0YTH
1991:
2.84 Gear Ratio:
2.97 Gear Ratio:
3.06 Gear Ratio:
3.33 Gear Ratio: 1WXH, 1YAH, 1YDH, 1YHH, 1YSH, 1YTH
1992:
2.84 Gear Ratio:
2.97 Gear Ratio:
3.06 Gear Ratio:
3.33 Gear Ratio: 2YAH, 2YBH, 2YKH
Sources:
http://spacecoastfieros.com/tech/440-4T60/index.html
GM Service Manual, 1989 LeSabre/Park Avenue, Sec. 7, Pg 440-T4-3
viewtopic.php?f=6&t=6634&p=45558
http://www.pontiacbonnevilleclub.com/fo ... 8&start=20
Authors: Alibi