4 Speed Transmission ‘68 1600

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Rans
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4 Speed Transmission ‘68 1600

Post by Rans »

Finally been able to turn wrenches and make a little progress on my project! I was inspecting the transmission for damaged gears but to be honest, I don’t really know what I’m looking at. Gear in the 1st pic seems to have wear marks right in the middle…should I be concerned about this? Next 2 pics There are 2 parts where it looks like teeth are missing but look very straight…are they supposed to look like this? Any suggestions wear parts I should replace while I’ve got the transmission out?

Everything turns smoothly by hand and there’s no issues shifting in any of the gears but I have not had the chance to test under power.

Should probably note this car hasn’t run for last 10 years. 96k miles on the odometer.

Any advice for a newbie is appreciated! Thanks!
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jrusso07
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Re: 4 Speed Transmission ‘68 1600

Post by jrusso07 »

The line on the gear is common and not a problem. I suspect it is from the gear manufacturing process, but I don't know for certain. Other 2 pics look like that is a warner syncho ring. These should be brass - cant tell from the pics (too much oil) but the missing teeth is how they are made. See pic in this link http://www.datsunroadster.com/PIC_PAGES ... rts_BW.htm

Is the transmission out of the car? If not, check for any movement in the counter shaft by pulling/pushing it in and out. If it moves, you may have shaft wear or case wear. If the wear gets too much, the gears with grind and fail.

If out the car, you may want to tear it down and look for wear, change bearings and synchros.
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tjp
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Re: 4 Speed Transmission ‘68 1600

Post by tjp »

jrusso07 wrote: Mon Mar 20, 2023 7:58 amIf out the car, you may want to tear it down and look for wear, change bearings and synchros.
If you have to rebuild your four speed, you might as well upgrade to a five speed.
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redroadster
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Re: 4 Speed Transmission ‘68 1600

Post by redroadster »

If you power the imput shaft with a heater hose and 1/2 " drill you should hear if it sounds smooth I used to do it with a hole saw bit in the drill side
See if there are hairline cracks in syncro sleeves but may have a Speed gear needle bearing rusted from sitting , those hard to find
Last edited by redroadster on Mon Mar 20, 2023 5:22 pm, edited 1 time in total.
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spyder
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Re: 4 Speed Transmission ‘68 1600

Post by spyder »

Most definitely replace the syncros while it is open. It they wear too far it can lock into one gear.
Rans
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Re: 4 Speed Transmission ‘68 1600

Post by Rans »

Thanks for info and advice! Cleaned up the gears and appears I have servo syncros. I have the transmission on my workbench so I’ll pull the countershaft to inspect and see if I have a matching countershaft.
Rans
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Re: 4 Speed Transmission ‘68 1600

Post by Rans »

So…I’m not sure if I’m missing something. Was fighting the front cover on the transmission today. Removed the T/O bearing, clutch fork, bolts holding the cover on…bugger won’t come off. Tried a pick, small pry bar to catch edge and pliers in the bolt hole…won’t budge. Is there something I’m missing or some method to get the cover off? TIA!
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david premo
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Re: 4 Speed Transmission ‘68 1600

Post by david premo »

Strike it with a rubber mallet a few times. If nothing else you feel better.
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Re: 4 Speed Transmission ‘68 1600

Post by Rans »

david premo wrote: Tue Mar 21, 2023 10:41 pm Strike it with a rubber mallet a few times. If nothing else you feel better.
Tried that too…felt WORSE! Had to resist getting the sledge hammer
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david premo
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Re: 4 Speed Transmission ‘68 1600

Post by david premo »

Spray carb cleaner on the cover around the sides and let it soak in for about an hour and try again. It will come off, someone probably got heavy handed with gasket sealant.
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FergO2k
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Re: 4 Speed Transmission ‘68 1600

Post by FergO2k »

I always read any topic that has a comment by David Premo....

I think I just found a new poster for the wall of my garage:
<< Strike it with a rubber mallet a few times. If nothing else you feel better. >>
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