The fill and drain plugs should be a 14mm allen. I'd suggest a 14mm hex bit socket for your ratchet. You're probably going to want it on a 1/2" ratchet or braker bar they are going to be tight.

It's a really simple job.

FIRST - Loosen the fill plug. If you pull the drain plug and can't get the fill plug you you are up poop creek.
Then remove the drain plug. Let all the fluid drain out. A good warm transmission will help drain all the fluid out quicker. Once it's drained put the plug back in and fill it until the fluid drips out the fill hole. Put in Dextron ATF. I've had Redline MTL in mine before and I started getting some grinding when I down shifted from 3rd to 2nd. I put ATF in and it went away and has been shifting great ever since.

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