newb Allison question

[Ian7]

Guys, can't find an obvious answer via search.... I've seen references to an "Allison Control Main filter". This isnt the main tranny filter is it? it seems a separate filter, but can't locate it. If so, change it how often?
Guidance much appreciated, thx in advance.

[DmaxMaverick]

The "Control Main Filter" is the external, spin-on filter. It's on the left side, and looks like a mini oil filter. It also has an internal, traditional ATF filter, which is ONLY serviced at overhaul.

[Ian7]

thx.
If I spin it off to change it on this new-to-me 113k mile truck just on principle, will it pour fluid out, or do I just lose whats in the filter?

[DmaxMaverick]

Very little fluid will be lost. So little, you won't notice it on the dipstick. 2-3 oz. in the filter, and very little residual will drip from the nipple area once removed. Be aware of the magnet. There is a doughnut-shaped flat magnet positioned on top of the filter, that fits around the nipple. Make sure you clean and replace it. Many folks have tossed them out with the old filters, and they are hard to find outside of Allison distributors.