Allison planetary gear swap

[duramax400ci]

Hi i was wondering if any one has swapped out the allison 1000 planetary gears for the allison 2000 planetary gears? i know that the 2000 planetary gears have different gear ratios. And if so what was the outcome of it was it faster, tow better? Thanks for your time in advances

 

[boominator]

wouldn't it code for output ratio being off ?

 

[Mike L.]

It will get slower and it won't code.

 

[duratothemax]

wouldn't it code for output ratio being off ?

It will set incorrect ratio codes and not even make it past 1st gear if you change to the 2000-series planetaries while keeping the stock TCM tune, but once you change the ratios in EFILive, it will be fine. I tried running a TCM from a 2000-series allison (in my 1000 series) without changing the ratios in EFILive and it immediately failed the 1-2 shift. Once I changed the ratios in the TCM tune it worked fine. Shifted like a dump truck and generally drove like crap though.

I have no idea why you would ever want to change to 2000-series planetaries though. Totally ridiculous and pointless. If GM thinks the 1000-series planetaries/gear ratios are good enough to 30,000lbs GCWR, (on the 2011+ 2500/3500 trucks, they are rated to almost 30k lbs GCWR) then its good enough for a 2001-2010 truck that is rated at several thousand pounds less towing capacity.