I know this has been talked about on here but I was wondering I have a 2005 2500 chevy D/A CC It Has 23000 Miles Im going to change the spin on filter today . The tranny has stock dex III H in it can i fill the filter with Dex VI or should i use Dex III H Thanks for any Info

I can't find the literature right off hand but there's a serial # cutoff on the Allison transmissions that can point you towards the correct fluid that you'll need. Someone will step in and tell you for sure, but I'm almost certain your 2005 will take Dex III. To be certain do some reading up on Allison's website, it's loaded with information about their transmissions.

Serial #6310670488 and up is compatible with Dex VI;)

The local Allison dealer told me not to bother filling the filter. With the amount of fluid that is in the tranny...the amount the filter held wouldnt make a dent in it. I check my levels a few times after changing the filter and the level on the stick never moved.

I would change the filter and the trans fluid at the same time not just replace the filter

he is talking about the external spin on filter. if you changed the fluid everytime you changed the spin on your crazy.

Thanks for all the info this is a great web site with tons of good info I decided to put the Dex III H in the filter so its all the same Thanks again eveybody

M&f

Id just get the allison spin on and put it on if you have enough fluid in your trans. If you need to ad, I would put transynd in.

I fill my filter with TranSynd before installing, as I have TranSynd in the tranny. Just a personal choice.

Where is the serial number located on the transmission? Thanks

The plate is on the passenger side, rectangular aluminum, riveted on side of transmission.

Thanks