tranny oil?

My s10 is doing same noise at 3rd and 5 gear, it looks like it has a like on top Of the tranny were the shift lever knob goes in. I guess my question is which transmission do I have the Borg-Warner T5 or the new venture 1500 or 3500 in order to get the oil. I look under the truck and the only number is 18563 and 18435 on the right side how can I tail which tranny is it my VIN # is1GCCT14Z5R8171036 THANKS