Removal of Type R Gear Case

I'm attempting to remove a gear case (to expose the gears) on a Type R transmission. I've removed all of the bolts and am able to raise the gear case approximately 1/8 of an inch. Apparently, the snap ring near the top of the case must be removed to allow the case to be completely released. I've used curved needle nosed pliers in an attempt to remove the snap ring, but no success. Any ideas? Is there a specialized tool as the access hole is extremely small?

Thank you.

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