Ever break this? (transmission)

[benracin]

I've heard about syncro's, maybe a gear, but what about breaking rod/shaft?



(never tried an image, hope this works!)

Ben.

[joeg]

UGHHH!

Ben, anything can break. All you need is a little nick, then a stress riser/ crack and a sudden load.

Bang, broken part.

Good Pic.

[ddewhurst]

Darn it Ben, I told you that ya could power shift a street port but that the bridge port power would break the counter shaft when going to 5th.

On the serious side as you know something caused that break. Ya need to find the cause. I have never had the counter shaft out of the bearing plate. From the picture it looks like the outside diameter had been broke (dark color) for some time previous to the inside breaking (light color). I presume the shaft is being held & the shown splines go inside the inner bearing race (gear shoulder to bearing). Is the break within the bearing inner race length or closer to 1st gear ? From the picture it looks like there is an undercut at the break. From the picture it also looks like the spline outside diameter has been rotating on the inner race of the bearing (light color on the outside of the spline). How is my guess work from one picture ?

Have Fun
David

[benracin]

Good guesses David, and to tell you the truth we were kind of at the end of the night so we both went, "Wow, neato! Lets go get some food" and left it lying on the floor, so you have actually looked more into it than me! This was Wednesday night, so let me see what I can remember. The other side of that shaft is actually sitting right in the bearing, almost like it broke off flush. The gear has sliden down the shaft that John's hand is holding. Although we haven't looked or tested this idea, but we were maybe thinking that the bearing it rides in had gone caput and led to the shaft breaking. I'm heading out this weekend so I guess my research will have to wait a bit. Pretty darn cool though. Oh, and a lot of the darkness is the trans fluid. It's like a muddy purple.

[dyoungre]

Just wanted to beat Jake to the punch - maybe I can get lucky here:
Is the shaft supported by bearings on both ends? If so, I bet the bearing further from the break is sloppy. There was some serious bending load on that shaft, suggesting that it was in single shear, not double, as intended.

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Dave Youngren
NER ITA RX7 #61