Transmission gates

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Gregs672000
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Transmission gates

Post by Gregs672000 » Fri Aug 16, 2019 12:12 pm

Greetings, my transmission has always been a bit resistant going into first gear after coming to a stop. The stick requires some pushing to notch in, a couple of tries, sometimes an extra pump of the clutch. I don't think it's a clutch engagement issue, as if I slowly let the clutch out while pushing on the gate it will eventually engage and spin the gear, indicating that the clutch was doing its job to separate the two. I have tried adjusting the clutch, but again I think I'm getting full throw. I have also noted that downshifting from 3rd to second is getting scratchy unless I'm slower and carefully rev match... synchros?

Transmissions are one of my weaknesses. Can someone tell me what could be causing this resistance going into first? Thanks!
Greg Burrows
'67 2000 #588
Tacoma, WA

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fj20spl311
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Re: Transmission gates

Post by fj20spl311 » Fri Aug 16, 2019 1:02 pm

I am no expert, but I recall that some times the shifting fork gets "bent".
It seams reasonable that would make it hard shifting if the slider is pushed toward one side.

Second gear sounds like the synchro
Phil
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SLOroadster
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Re: Transmission gates

Post by SLOroadster » Fri Aug 16, 2019 2:21 pm

It might be a couple of things. First off, the syncros on both could be tired. It might also be that the roll pin in the shift fork is sloppy, or the shift fork itself is worn out.

In 2010 I broke the roll pin that holds the fork onto the lever. Sometimes I could get it to shift, other times, not so much. I thought I had a broken shift fork, but it was simply the roll pin used to hold everything together. I always rev match, but I also have issues getting into 1st gear from time to time. I'm guessing its the syncro.

Will
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Gregs672000
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Re: Transmission gates

Post by Gregs672000 » Fri Aug 16, 2019 4:39 pm

Thanks for the replies... I think I'll be pulling the motor this winter to fix the damn rear main leak (never had one leak until now! Grrrrrr) and have the box gone through again. Wasn't that long ago. Still, should have listened to myself and had it inspected before the new motor, but was hoping it was the screwed up pilot bushing. BTW, the thrust bearing issue I posted about a while ago definitely was caused by the mis-located pilot bushing.
Greg Burrows
'67 2000 #588
Tacoma, WA

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redroadster
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Re: Transmission gates

Post by redroadster » Fri Aug 16, 2019 10:46 pm

The taper on a New speed gear looks / is like a new brake rotor
and 50 year old one is GLAZZZED & warped. Plus the splines can be wiped and worn
Most sport manuals went to clutch material insert brass rings in the 90s and drove / shift like you want longer
When we had someone wanting a manual trans rebuilt and wanted it like new they were told ...buy new
Last edited by redroadster on Sat Aug 17, 2019 8:00 pm, edited 4 times in total.

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Datrock
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Re: Transmission gates

Post by Datrock » Fri Aug 16, 2019 11:47 pm

It is documented that Nissan changed the brake bands in the Servo type 1st gear hubs, its the part under the steel ring. Years ago Rallye even had a writeup on the new 1st gear and how difficult it was to engage into the gear. So it might be worth checking into if you are tearing into it. If you have the bad one you'll have to change it out since the two gear hubs that were used for the 1st gear are different.

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Gregs672000
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Re: Transmission gates

Post by Gregs672000 » Sat Aug 17, 2019 2:02 pm

Thanks gang, keep the info coming!
Greg Burrows
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Tacoma, WA

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jhayden
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Re: Transmission gates

Post by jhayden » Sat Aug 17, 2019 6:21 pm

Datrock wrote:
Fri Aug 16, 2019 11:47 pm
Years ago Rallye even had a writeup on the new 1st gear and how difficult it was to engage into the gear. So it might be worth checking into if you are tearing into it. If you have the bad one you'll have to change it out since the two gear hubs that were used for the 1st gear are different.
p. 169,Datsun Roadster Parts Catalog, Rallye Enterprises, Ltd, 1983

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Gregs672000
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Re: Transmission gates

Post by Gregs672000 » Sat Aug 17, 2019 7:40 pm

Thanks, Dan was/is a great source of knowledge. I used to have the books but I'm not sure where they are at the moment. I think it's online.
Greg Burrows
'67 2000 #588
Tacoma, WA