I took off the tranny and I'm getting ready to put it back in. I have a new rear main seal and housing gasket, but mine doesn't seem to be leaking. (it's the engine's original seal. engine has about 50K miles) Should I get it replaced anyway? Where can I get a puller for a seal that big?
I'm assuming I'll have to drain the oil to do it?

Thanks!

 

If it's not leaking, I wouldn't replace it. When I changed mine I was able to pry the old one out with a screwdriver; there's small "flats" on housing made for this purpose. I also used a piece of PVC tubing and a flat metal plate to tap the new one in place evenly.