[cbongo247]

your 89 most likely has the 700r4. not the best tranny, but better than the 86s and older. they are easily built and can handle around 400hp range. fairly durable. the 4L60s came out in 90 or 91, then were upgraded to the 4L60Es in late 93. the E stands for electronic overdrive. as long as you chang the fluid and keep these two trannys cool, they will treat you well. unless you are planning on major wiring upgrades and swaps for the 4L60e, your best be would be to go with a rebuilt or built 4l60 depending on your budget. but a I would highly reccomend at least a 2500 stall converter, i have one in my 94. great on the street and even better at the dunes! also install a shift kit. high performance or towing modle wichever has a more firm shift. any more qs let me know.
kyle.