There is a special pair of heavy duty snap ring pliers with serrations on the tips that grip those snap rings properly. Check with Snap-On or K-D Tools, or possibly K-Line or Goodson. You won't find them at any of the tool discounters like Harbor Freight or Northern Tool, because very few people rebuild standard transmissions any more.
Jerry

"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln
Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt!
There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway
Love your enemies and drive 'em nuts!