As I understand it, the Japanese versions (Super Sentai, Dairranger, Carranger and so on) were totally different by way of plots and characters. It's fascinating reading about how they managed to cobble together the American shows! The first series of MMPR was meant to be 40 episodes long, but it was so successful they extended it to 60 - problem was, they'd run out of Super Sentai footage, so they had to commission some totally original stuff. Lord Zedd was created solely for the American series too.
At various points, they didn't have the right Megazord costumes for whatever configuration they needed, so they were really struggling to make episodes gel. Oh, and at one stage, they actually used footage of some of the tie-in toys for an Ultrazord combination (I think it was Titanos and the Shogunmegazord, which were from two different series in Japan and thus would never have been filmed together originally).