Allison trans

[GMC or nothing]

Does anyone know if GM put the Allison 6 speed transmission in the 1500 Sierras? I have a 2010 with the 5.3 and tow package that is awesome. It also has the Eaton diff. but the transmission has me confused.

 

[Molson02536]

Does anyone know if GM put the Allison 6 speed transmission in the 1500 Sierras? I have a 2010 with the 5.3 and tow package that is awesome. It also has the Eaton diff. but the transmission has me confused.

The transmission your Sierra has is a 6L80E with a tow option specs. The larger Sierra's came with the Allison, hope this helps you understand more about your 6 speed transmission.