914 tranny strength, What have people seen actually break? Options

[r_towle]

Take a newly rebuilt tranny.
what is the weakest link (aside from first gear burnouts)

What breaks?
Is it the bearings that cant handle it? I dont doubt it...its a flimsy looking thing.
What else breaks?

I am talking about large motors, V8 conversions etc...

Looking for real world events...no speculation.

Rich

[John]

With sticky enough tires, sufficient torque and and a bumpy enough race track, I can strip the teeth off of 4th gear in a 901.

We have driven the car (track only) for the last 24 years. Maybe 10-12 years ago, it started happening. Rebuilt the original trans, it happened again same gear, same turn. Used a different fresh box and it happened a third time. All the bearings still looked good, the shafts all measured good, the pinion and crown wheel all were still good. I rebuilt the original box one last time with a billet intermediate plate and we decided to go the 915 route. Now the rebuilt 901 box with the billet intermediate plate lives in my street car (with a 3.2). No problems in the last 8 years on the street with the 901 mated to the 3.2.

Likewise, the 915 has not stripped any gears. It did manage to begin to destroy the crown wheel, but we found that the ring had not been properly set up. It is now.

I have seen teeth stripped off of gears, I have seen bearing cages come apart (especially the roller cage on the pinion shaft). I have seen needle bearings flattened, and I have seen a shift fork slid on one of the internal shift rods.