I cannot find anywhere on Chevrolet's website where it says the actual model number of the transmission. I'm assuming that the 2006 has the same transmission as the past few years, the L460E...right????

My filter catalog does show that they are still using the 4l60e, but you can get the 4l80e, or the allison depending on the truck.

yeah they still use the L460E but they upgraded it in 2002 . I missed it by 1 fargain year..

Here you go:

http://www.gmcanada.com/english/vehicles/chevytrucks/silverado/silv_opti.jsp