Rear main oil seal

The vehicle is a 1995 chevy surburban 1500 4wd.
engine is a 5.7 l v8
The oil seal is leaking and needs replacement. Can this be done by removing the transmission only or do you also need to revove the flywheel and oil pan? In one manual it stated that if you have a special tool you dont need to remove the oil pan. Is this job worth doing myself? I have replaced transmissions and cluches before.
Thank you for any info that might help!

Tim Lehmann