Good time to do a 5R55E swap?

I might be picking up a 1996 Ford Explorer (4dr, 4.0 V6, 4x4) this upcoming week for $500 delivered. Runs, but doesn't drive. PO says it sounds like the torque converter.

The Explorer did not get to the 5-speed automatic (5R55E) until the 1997 model year. I've done a little bit of reading and what I've found is that the only difference between the 4R55E (4-speed) and 5R55E (5-spd) is that the 5R55E is stronger internally and the neutral safety switch is different. The bellhousing, transmission casing, transfer case, driveshafts, and overall transmission length are all the same!

Sounds like it might be a good time to do a 5R55E swap if I get this Explorer, because the transmission needs to come off anyways!

Do you guys advise just replacing the torque converter (and risk a potentially bad transmission) or go ahead and try the 5R55E swap?

PS: I can find the transmission as low as $65 at a local junkyard, complete with everything (versus $120+ for the torque converter alone. The trick is just to find that looks newer/more recently rebuilt or find a wrecked Explorer that has one.

No difference between the internal parts or torque converter in the 4.0. Go with the original transmission either rebuilt or find one in junkyard. You can find local shop at ATRA.COM for estimate to rebuild if you go that route