Datsun Roadster Forum-311s.org

My '68 1600 has a 90 degree speedo pinion gear adapter that backs up to the frame. The clearance between the back end of the adapter and the frame is not touching but very narrow. My question is whether the adapter can be removed from the transmission without removing the engine and transmission from the car or cutting out part of the frame. I have not removed the retainer plate holding bolt yet and that may be the answer. I just don't want to get in too deep and then find out the pinion adapter was installed before the car was built around the engine and tranny.

You should be able to remove the 90° adapter without any problem. You do not need to remove the screw and retaining plate. Just unscrew the adapter from the transmission drive. The 90° adapter attaches to the transmission just like the speedometer cable attaches to it.

Now having removed the 90 degree adapter and yet to pull the pinion case and pinion from the tranny and viewing videos of other Nissan (not roadsters) speedo pinion removals, I see on those videos transmission oil draining once the pinion is pulled. Will pulling the pinion from my 1600 drain the transmission? My car is on jack stands in my garage with no ability to refill the transmission. I'm expecting I should get it to a service shop with a lift that can refill the tranny before pulling the pinion and of course having the new one ready to install? If it won't drain the tranny to pull the pinion I can proceed in my garage. What should I expect upon pulling the pinion case?

Bump! Doesn't look like anyone answered! I don't know, having a 5 speed...

Just like the 5 speed, the speedo drive is in the oil, so oil will come out. Not sure how high your car is om the jack stands but re-filling the oil almost always requires a syringe to push oil into the fill hole which is on the driver side of transmission about halfway up the case. See the green items in the diagram for the fill location and plug.

The fluid level with the car level comes to a bit below the the top of the cluster gears the speedo pinion is off the output shaft 3 " above the speeds don't set in the fluid , but when driving fluid is thrown everywhere in the Trans
If your having sycro shift problems ,lowering the oil level 1-2 inches can help as it doesn't throw as much oil up
These are lite use cars really

Thank you jrusso07 and redroadster for the defining details and also Gregs672000 for bringing this question back to the forefront of discussions. I now know my path forward. Got to source the new pinion other than from Dean who is closed until 01/25/25. Merry Christmas to all.

Yeah, glad to "help"... thanks family!

Installed the new pinion. The one that was replaced, probably the original pinion, was visibly warn and that may have been the reason for the speedo needle bouncing instead of steadily pointing since I bought the Cahhh in 1995. But the new pinion did not fix the problem of the speedo not working. The wound snake cable that does the rotating was broken. The original was 75 inches long and found a suitable replacement - Pioneer CA3087. This has a connector to the back of the speedometer that is a slide-on and latch device. The needle now shows limited wiggle but does not bounce like the old one. In the photo, old (original?) cable on left, new Pioneer CA3087 on right.

Glad you got this sorted out, and ultimately added to our collective knowledge.