trans issues, it broke.!!! Options

[orangecrate]

72 4 popper. 1.7 What would cause the pin in the in the tailshaft linkage to shear??? It has a u shaped recepticle on the outside that links it to the linkage going fwd and on the inside there is a finger of sorts that is pinned to the shaft that operates the internal shift rods. That pin shears. What could be hanging up with enough resistance to cause this pin to shear??? I'm stumped. I's happened twice now.
I've gone thru the trans and replaced 1-3 syncro rings and dog teeth ,1-R gear and all 4 shaft bearings. I've adjusted the internal linkage with a shaft template holder. Now it shifts really hard and I don't want to shear the pin again. It leaves you by the side of the road with a tow being the only recourse.
Has anyone messed with the detent springs in an effort to make it shift easier???
!st time a guy pulled out in front of me on the hiwy and I downshifted to 4th. When I went back to 5th there was nothing. I was in neutral it seemed. No apparent internal damage but the sheared pin!! 2nd time I was back from playing on a local twisty. Pulled up to a stop sign , took off ,hit 2nd , same thing . Nothing . no grinding no noise . Vroom vroomm no go. Pulled it apart again and did all the aforementioned stuff but found no internal damage other than syncro and dog teeth wear. and a sheared pin!!! What should I be looking for this time??? (IMG:style_emoticons/default/headbang.gif) (IMG:style_emoticons/default/confused24.gif)

[flxzcat]

OK, I'll assume you are not muscling that shifter like a Hurst at the dragstrip. (IMG:style_emoticons/default/calvin.gif)

Removing the shift linkage from the console. Can you shift the finger assembly part into the 5 forward gears by firm (sometimes very firm) hand? Yes, good. No, bad.

Re-assemble the shaft and "finger" and look into the drilled hole to see if it a clear round hole or if there are offset of the holes. if offset, you may need to flip the finger so that the through hole is aligned. If it has a staggard offset, the pin may be getting damaged on assembly.

Furthermore, you might double check the tunnel/rear shift linkage rods to make sure they are not binding up somewhere like inside the tunnel. Did you work on your seatbelts lately? A screw at the tunnel mount that is too long can rub hard on the shift rod (at least with my Tangerine version)

Detents are not accessible without removing he gear stack as far as I know.

[Jack Standz]

We too have one of those tail shifters, in spite of what others may say, when properly adjusted and parts aren't too worn it worked fine for us (when it was on the road).

What gear oil are you using? Those 54 year old 901 transmissions use good oil dynasour oil. Not the good slippery stuff we use today. These transmissions need some friction to work right. Without the proper gear oil, you may be overworking that pin. That's my guess. Either that or some mechanical problem. Best wishes for fixing it.

[orangecrate]

I managed to get the finger at the end of the long shift rod out of the tranny connection and the linkage shifts like butter!! Something in the tranny.