I just bought a used 2005 Silverado 2500 HD 2 wd with the Duramax engine. It doesn't have the Allison badge on the side so I was wondering if anyone could tell me what kind of tranny is in it and if it's any good..? I apologize for the stupid question but I am new to this. Any help is appreciated.

 

is it 6 speed?

 

I didn't know that any other trany other than the Allison came with the DMAX, the Allison badges just started showing up a year or two ago that I have noticed.

 

Easy way to tell... Lay down on the driverside and look at the front left of the trans.. If there's a red spin on filter that looks exactly like an oil filter only more honda sized (about 3" tall 2.5" wide) then you are the lucky (or unlucky depending on it's condition..) owner of an Allison.. If you don't see this then what you have is an 4L80E which is also a very good trans!! It's basic design has been around forever.. It's a beefier and electronically controlled version of the TH(Turbo)400.. GM only started adding the Allison because they bought Allison...

 

Thank you Matt B. I appreciate the information.

 

Did you figure it out? I am a little curious on this one also