Compatible Allison 1000 transmission years?

[CByz]

So recently I cracked the bell housing to my transmission and it lost all the oil, so I’ve been looking at good used transmissions. My question is what years are compatible with the 2006s? I’ve heard the plugs vary year to year making some incompatible with different years. Any advice would be awesome. 

[CamGTP]

It has to be a 2006 or newer Allison 1000 because all of the 2001-2005's were only 5 speeds and 2006+ added the 6th gear.

 

From a little looking you can find them in Silverado/Sierra's and Kodiak and Top Kick model trucks. Also the 2006-2009's "should" all be the same and then in 2010+ there are valve body and many electronic changes so those won't work with your truck.

[Kstroud9]

Just out of curiosity, would a 2006+ Allison work in a 2001-2005 if the only difference is the gear change?