It's possible to fix this yourself. I would confirm it won't void the warranty. Half-hour's work. The pump can be pulled by threading a few SAE bolts into the bolt holes in the front and using a claw-hammer and prybars on the bolt heads to gradually wiggle the pump out. The areas to be concerned with pulling the pump are to the sealing rings that go into the overdrive planetary, getting the two pump housing pieces realigned perfectly, preserving the outer seal, and checking the pump-to-case gasket for damage and replacing if necessary.
If you have a set of drill bits in 64ths they can be used as alignment pins.
The bolts that hold the cast iron cover to the cast iron pump housing, and the bolts that hold the pump assembly to the case are all torqued to 18ft/lbs. Getting the cover aligned right to the pump housing is critical - if not perfect it will bind going back into the case and/or the case bolts won't thread in. You can use petroleum jelly (Vaseline) to hold the paper pump gasket still in the case, and to lube the the outer gasket and sealing rings.

 

Thanks for the tips. No warranty to worry about, I found the transmission on Craigslist. I have no clue who did the rebuild.

Thanks, I downloaded that manual earlier today.