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4spd tranny questions

Posted: Tue Sep 03, 2019 9:24 am
by dynaguy
Not really much experience with transmissions. What input on determining condition based on these pics, Syncros etc? There is some play in countershaft. TIA Pat

Re: 4spd tranny questions

Posted: Tue Sep 03, 2019 12:31 pm
by Mackn367
Hey Pat. I just had my hands in there the other day haha. So I was advised by JT @ DatsunRestorationProducts to replace my counter shaft - which I did. I recommend taking yours out and inspecting it. I guess that's a common piece that needs to get replaced if it's original. You will know when you pull it out if it needs to be replaced. Mine actually wasn't terrible but I still replaced the shaft along with new bearings (since I was already there) and I recommend the same.

Edit: Oh and when you remove the gear and counter shaft don't forget to save the metal washers on each end and remember their orientation and which side each was on. Tech wiki will help you if you forget to make a note.

Take care!
- Nick

Re: 4spd tranny questions

Posted: Tue Sep 03, 2019 8:33 pm
by redroadster
I look at the blocker ring splines those look in sharp shape not wiped rounded, try to see feel if any caged bearings are loose, Any wear on the shift forks , you can punch out the roll pins and shift move the sleeves to see how easy it goes 1st to 2nd & 3t4th
With it much work to try , it would be worth riging up a belt drive on the imput shaft to feel the shifting
Loose belt

Re: 4spd tranny questions

Posted: Sun Oct 06, 2019 8:20 pm
by jarhead
I just went through this. Countershaft is common wear item that should be replaced if any question. Was there any concern when the car was driving? Its' tough to tell by looking. But driving problems are a better gauge.

Re: 4spd tranny questions

Posted: Sun Oct 06, 2019 10:15 pm
by JT68
If there is any play in the countershaft, you need to fix it-gear destruction comes next and without warning.