what breaks in a rb20 transmission?

[jdmser]

I read over and over again that the rb20 are "weak" but, no one seems to say why. What tends to break on them.....snycros, input shaft, gears etc.....?

[DriftingisLame]

I hear they're super weak from RB25/26 guys, although, I've never heard of many (or any to be honest), breaking from too much power. The transmission's the same as the KA, and my buddy had 400+ rwhp for quite some time with his ka trans, no problems.

Now from personal experience, My rb20 trans needs to be rebuilt due to an input shaft bearring wearing out, but that can happen to any trans, its not from too much power.

[OpeLok]

I've broken my 20 trans once. It was the 5th gear/reverse shift selector fork that snapped in half. My car was stuck in reverse. This piece is a direct crossover to a KA trans which I bought from Nissan. Rebuild kit was from a place called AXIOM for a KA trans. Only 2 syncros worked. All bearings and seals did crossover however.