1996 Mazda B4000 Transmission question

[tivouser08]

So I have my 1996 Mazda B4000LE.. Has the 4.0 6 Liter...Automatic. I am guessing I have about 350,000 miles on it. Not 100% sure, may be more as the odometer stopped at 152,000. What is the equivilent Ford part number for a new, or used transmission...if there is one? Can I use one from an Explorer from the same year? I love this truck..am getting about 19.1 mpg on highway trips..but..as of late I can tell a noticiable difference in the shifts.

*Edit...found the brake light link on here...still need some info about the trans...

Thanks,
Brett