How can I tell what Tranny I have? I have seen references to 1000 etc? I need to change the filter, etc. Does the model make a difference?

our pickups have the allison 1000 series.

There are 2 filter, as you may know, a spin on, and one in the pan. If you go to most dealers, they should be able to help you get the right filter. I don't know the interval for the internal filter change, but the spin on gets changed more often.

I believe the internal filter is basically a screen, designed to pick up larger pieces if a major problem is to arrise. If you were to drop the pan and swap it out for a deep one i would change it then if not dont worry about it.As far as the spin on i change mine at each oil change 8-10000 km. when changing spin on filter make certain you clean the magnet thats located on top of it and replace it prior to reinstalling it.

duratys-

do you fill the new filter with ATF before putting it on? Or do you add say half a quart from the top once youve installed the new filter? Ive only changed my spin on once in 26,000 miles and flushed the system and refilled with synthetic atf at the same time. Im most likely only going to do the spin on every 15,000 miles or so but wasnt sure as to whether or not it is necessary to fill the new filter before putting it on.

I never have but i make sure to check fluid level after the trannys up to operating temp. I dont see why you couldnt though. How much crud did you find on your magnet the first time you changed it. I have noticed that each time i change the filter there seems to be less and less each time.

i found virtually none the first time, Im gonna change it again as soon as the gods stop pissing on me. Im now interested to see what I will find. What type of crud did you find? metal pieces or sludgy type crud?

Sludge

It's interesting that they put magnets in the filters, which I have no problem with, but the problem is that much of what wears and ends up in the oil is not magnetic. Brass, babbitt, copper, all sorts of non-ferrous metals. I do really like the external filter on these transmissions. The internal filter is to be replaced only when the trans is rebuilt, no need to before that.