I found this description of the probable 1998 4 speed Corolla AT online:
A245E (1993-2007 Corolla) Gear ratios: 1st - 3.643:1 2nd - 2.008:1 3rd - 1.296:1 4th - 0.892:1 Rev - 2.977:1
(SOURCE:
https://answers.yahoo.com/question/i...6064903AAutAc0)
So calculate the freeway RPMs for the tires and check a freeways speeds, at low light throttle and that will strongly suggest whether you have a four speed transmission. You could also accelerate watching for the shifts on the tachometer or using the butt-ometer built into the driver seats of all cars. Good luck
EDIT: I just realized the gear ratios I posted in this post do not include the final drive gear, so unless you can find that info, this won't help you. But counting the shifts and watching the tachometer will tell you and maybe that is easier.