Transmission Codes?

[MtnDewd]

I'm trying to find replace my O2 Sensors on my 99 Hoe and i was asked what transmission code my hoe has...4L60-E or 4L80-E. How can I see which tranny I have?
Many thanks...

 

[05Yukon]

I believe it has the 4l60e but if you post in the correct section they should be able to tell you for sure.

 

[MtnDewd]

Thanks...not sure how I got it here??