If you take off the oil pan will you need a new seal.

The gasket is reusable.

thanks now now napa says they dont have the filter were is there anywere else you guys know to get one

I got mine form a supporting vendor. http://www.merchant-automotive.com/filters.aspx

Or if you are in a big rush, a local Allison dealer.

filter in the pan doesn't have to changed as often as the spin on,so change the spin on filter ,drain the oil from the drain plug on trans and replace with 7 liters,or quarts,of oil,filter in pan only after failure,large particulates only,spin on is for the valve body,see your dealer for more info,if you change the in pan filter,add 2 liters/quarts,fill to top of cold mark on stick,do not throw out the magnet from the spin on filter,

well some guys are saying that the napa spin on filters is getting blocked by the magnet do u think this is true?

Better off just using oem filters and then there are no worries. Allison oem filters are the best you can get. My .02 cents worth.