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> The DREADED 1st-to-reverse, Have developed a process that is straight forward to prevent the 1st to Rev
ctc911ctc
post Oct 10 2025, 12:28 PM
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914-6 all original - rebuilt the transmission

This is part of the rebuild thread - http://www.914world.com/bbs2/index.php?sho...3371&st=100

Transmission - Shifter -> This is my working theory, I am probably wrong.... (IMG:style_emoticons/default/biggrin.gif) (IMG:style_emoticons/default/dry.gif)

While I am chasing the 'carb-spitting' issue, I am also chasing the shifter being.....OFF

This is manifesting itself as the DREADED 1st to reverse problem.......As to the condition of the 901, gears are all within spec, new syncs 1st and second, new slider for 1st reverse - new dog teeth for 1st and second.

Let me explain,

When I put the car into 1st or reverse, I (as well all of you) push the lever from RIGHT to LEFT and feel the spring pressure of the shift plate.

About 1/4 of the way to the full extent of the spring compression the there is strong resistance. BUT i can CONTINUE to push to the left. I believe that I have reached the limit of the various linkage components and that what I am REALLY doing at this point is torquing the linkage. I can then continue to torque the linkage until I have reached the full travel of the shift lever spring plate

Attached Image

What happens is; when the shift comes out of 1st, there is no SPRING BUMP to push the selector in the transmission from the 1st-reverse position to the 2nd-3rd or middle position.

I have cut pictures from Clay Perrine's excellent 901 cut-away to depict what is happening

Transmission is in Neutral on the other side of the selector bars is a vertical channel, there is a knob that is in ONE of the THREE channels - when moved the selected bar moves left to right

Attached Image

Now, the knob is in the channel of the lowest bar AND the bar is slid to the left for FIRST GEAR

Attached Image

My shift LINKAGE - not the shift lever - when moved forward never gets the BUMP from the spring and as a result STAYS in the LOWEST position THOUGH the shift lever HAS moved to the right and you think that the shift is in the correct place BUT NO, it ends up pushing the SAME slider BACKWARD into reverse

Attached Image

OUCH!!!!!

What should happen is the selector should get a bump to the next position from the spring and end up here.

Attached Image


MY PLAN

I am going to adjust the Shift bar about 20 degrees to I do not get any mechanical loading, not sure if 20 degrees is correct......feels right.......
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Front yard mechanic
post Oct 10 2025, 05:39 PM
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Just remember it’s not gear grinding it’s gear polishing
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