I'll confirm from personal expirience what Gilly stated; w/o a new lock pin, the filler tube cap CAN vibrate and fall off.......

The 03 ought to have the 722.6 trans, right? If so, it should have a fill tube.

The newer (last couple of years) dot 9 trans must be pumped full of new fluid using the drain plug.

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Terry Allison
N. Calif. & Boca Chica, Panama

09' E320 Bluetec 77k (USA)
09' Hyundai Santa Fe Diesel 48k (S.A.)