Take no chances. When you use a funnel for pouring in ATF, ensure that this funnel has NEVER been used to put in AntiFreeze. It may sound silly to think of using one of these long, dunce cap looking funnels to put in antifreeze, but please take note.
The Allison Automatic Transmission folks claim, and I'm quite sure that they have lots of data to back up this claim, that using the same funnel you have previously used to put in Antifreeze will poison your automatic transmission.
The minute traces of antifreeze left on a funnel, no matter how well it has been wiped clean can destroy the clutch surfaces in your automatic transmission.
I suppose that Allison could be using different clutch material than everyone else, but from where I sit, an automatic transmission is too expensive to risk over a $3 funnel.
This sounds almost ridiculous, but the Allison people are dead serious about this.
'84 Euro 240D, 516K miles
'88 300E 5 Speed
'81 300D Daughter's Car
Over 800,000 miles in