I have the same year Tercel. Last year I had to remove one or the other as well, and I also chose to remove the transmission. The worst part for me was disconnectiing the drive shafts. I ended up leaving the driver side attached to the transmission. That worked fine. I put a sock on it to protect the boot (on the wheel side of the shaft).
Thanks guys. I'll yank the trans out. since it seems easier. I was just gonna drain trans fluid, pop both shafts from the hubs, loosen torque converter nuts, bell housing bolts then lower the whole thing down and remove the flex plate and do the seal.
I pulled the trans out today and replaced the rear seal. Only hangups were a stripped trans housing bolt head, and the torque converter hung up on the crank for a while as I struggled to pull it out. Other than that back up and running in less than 8 hours. I had to put a metal bar across the engine bay and tighten a tie down strap around the engine and metal bar to keep engine from tilting to far during the job. Sucking down brews now. Thanks for the tips.