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Full Version: No Teeth on the 4th/5th Selector
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ctc911ctc
'74, 2.0 - around 22K miles

Ok, this one i do not understand.

After watching Dr Evil's video, I decided to exchange the selector for 2/3 with the selector for 4/5. Though the teeth on the second gear side were still in good shape, I was putting in new dog teeth and thought this to be a good path. Thank you @Dr_Evil

So, I break down all of the gears, replace dog teeth on 1st and 2nd. Last thing to do is to swap the selector. I removed the selector from the 4th/5th position and this is what I found.

The side that faced 5th gear has NO teeth. They are not worn off, they are evenly flat all of the way around! blink.gif confused24.gif


The tranny had very mild amounts of metal in the oil, i put a magnet in the oil after it was drained to check. Pretty sure they were not ground down! Fifth gear worked great - never ground or had trouble.

Click to view attachment

The fifth side is FLAT, (above) not a point nor ANY wear where the points should be.
The fourth side is perfect (Below). Sharp even teeth with very little wear.

Click to view attachment

Has anyone seen this before? Guess I will need to either buy a 2/3 selector or flip it and hope for the best.......sigh.......

Any guidance is welcome..... confused24.gif

porschetub
I don't know ,I think transmissions are a some what of a mystery too me,34yrs as a mechanical engineer I have never opened one up.
The OP may not like to hear this but judging by the wear seen perhaps the mileage on this box maybe more than 22K ,several things come to mind ;
could have abused by PO,
original box changed out due to an issue,
replacement box somewhat worn out or close to it,
incorrect oil used in replacement box.
My car is a case in point,the PO had 2 of them to build one ,my car is documented low mileage of around 50K miles (our government records) but the gearbox has issues,I have found strong evidence to suggest the mileage is correct on most wear parts however some make me think the PO mixed and mismatched worn items off the parts car.
Hope this isn't your issue and you get it sorted ,good luck.
ctc911ctc
Thanks for the post, as an EE this is even more of a mystery!

What is pretty certain is the car was parked in 82 and I resurrected it in 2019. Someone could have taken out the tranny and already have swapped the shift selector guides in the late 70s/early 80s.............replaced 2nd and first with a new one......weird.

Unless i learn something more I will buy a new one and replace the 2/3 with a new and the existing 2/3 will go to the 4/5 position.

THANKS!

QUOTE(porschetub @ Aug 20 2020, 06:26 PM) *

I don't know ,I think transmissions are a some what of a mystery too me,34yrs as a mechanical engineer I have never opened one up.
The OP may not like to hear this but judging by the wear seen perhaps the mileage on this box maybe more than 22K ,several things come to mind ;
could have abused by PO,
original box changed out due to an issue,
replacement box somewhat worn out or close to it,
incorrect oil used in replacement box.
My car is a case in point,the PO had 2 of them to build one ,my car is documented low mileage of around 50K miles (our government records) but the gearbox has issues,I have found strong evidence to suggest the mileage is correct on most wear parts however some make me think the PO mixed and mismatched worn items off the parts car.
Hope this isn't your issue and you get it sorted ,good luck.

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