Originally Posted by
Jon Wehrenberg
Some related information to those changing their own transmission fluid or having somebody do the work.
First, the recommended filters are the high capacity. Those filters extend the filter and fluid change interval. I think they may be all that you can get anymore, but it does not hurt to verify it. The Allison part number for a pair is 29548987.
When changing filters keep in mind the bolts around the bottom of the filter housing are steel going into a much softer aluminum pan. While there is a paper gasket between the housing and the aluminum pan, the actual seal is at the O ring beneath the filter so excessive tightening of the six bolts is not necessary. The Allison specification for torque is 38 foot pounds. Even 35 foot pounds is adequate. If you or the mechanic uses an impact wrench or excessive torque the aluminum threads in the pan are easily stripped and the repair is expensive. Keep that in mind.
When checking the fluid level the coarse initial check is the dipstick. It is very hard to read and with a cold transmission as long as the fluid is anywhere within the cold range you are alright to do a road test and get the transmission up to temperature for a final fluid level check. When the transmission is hot push the two arrow buttons on the gear selector pad and after a suitable countdown the display will read the level. It should read O L followed by O k. If it is not OK it will tell you how many quarts to add if necessary. You can check transmission fluid status anytime using this method. Do the check with the transmission in neutral at low idle.