I want to change the transmission fluid on my 1995 isuzu rodeo. I have the Haynes book and I have changed the tranny fluid on many other vehicles but the book shows I should have a drain plug but I don't. I am wondering if I drop the pan I could drill and tap a drain plug or was it designed so the fluid is not to be drained in this manner? My Vehicle has over 200,000 miles on it so I want to change the filter anyway. Thanks.