Allison trans included in VIN?

[marine73]

Hello all. I'm new to this forum and I'm looking for a used GM Duramax with the Allison trans. Unfortunately, most used vehicle listings only indicate auto trans. Is there a code in the VIN which tells if the truck is equipped with the GM or Allison trans? And if there is, is it in the same position in the VIN for all years that the Allison has been available in the 3/4 ton pickups? I've tried to find a site that would decode the entire VIN for free but all I've found so far is sites that charge for this information. Any info/help would be greatly appreciated! Thanks

[DmaxMaverick]

Welcome aboard!

You don't really need a VIN translation for the tranny info you want. Transmission options, for GM, are dependent on the engine. If it has a Duramax engine (or the 8.1L gasser), there are/were only 2 options for light trucks (pickups). The ZF 6 speed manual, and the Allison auto. For the 2006 model year, the Allison was updated from 5 speeds to 6. No other tranny info is relevant for what you are asking.

[marine73]

Okay, thanks for the quick reply. I've had some (apparently uninformed) people tell me that GM was using a less capable trans behind the Duramax on some of their trucks. Glad to know that if I get a Duramax it will come with the Allison!

[DmaxMaverick]

Yep. A lot of misinformation out there.

The 4L85E is used behind the Duramax in vans and some chassis configurations, but the engine is detuned accordingly (250 HP). However, the 4L80E/4L85E tranny is no slouch. It's no Allison, but certainly capable of handling a lot of power while remaining very reliable. I wouldn't say "less capable", but they have their place, and the Allison is very well suited to Duramax power. A properly built and tuned 80/85 could be equally capable, for the right application. Late model GM auto trannies are considerably less of an issue, compared to the other brands. Manuals are about equal across the board.