| It would be a good idea to do both filters, it won't hurt. Besides, do you know the full history of the truck and how it was taken care of? I think GM states the internal only needs to be changed upon overhaul. Most guys and dealers (at least mine) will just drain the pan and add to fill up the tranny again. I read that will take about 13-14 quarts of fluid to bring it back up. The tranny takes a total of 24 quarts....obviously you won't need that since you will probably just drain an fill it back up. My dealer told me that they couldn't flush the Allison, so they asked me if I wanted them to pull the pan and change the interal while it was empty. Alldatadiy.com has a lot of good information on it. As far as online manuals, I don't think they are offered. I do have the owner's manual and diesel supplement in electronic format that I could send you if you didn't get those with the truck. Just PM me your e-mail.
__________________ 2004 GMC 2500HD D/A CC Carbon Metallic w/ LB7
4" turbo back MBRP exhaust
TST Powermax Programmer, Diablosport Predator
285/75-16 BFG T/A KOs, Eagle Alloys Series 187
Clifford 2 way remote start, High Idle, Bilsteins
Extang Classic Platinum Tonneau Cover
AFE Magnum Force Stage 2 Proguard 7 intake Kennedy Diesel Merchant Automotive My Photos |