Mystery Transmission ID help needed!

[JR Ohio]

Hello all. I need help from you Datsun CSI folks trying to identify the 5spd transmission I bought for my ’72 240Z.

Here’s the scoop

It has one mounting ear on the tail shaft. Has the long shifter mount. Those being said, it would appear to be a close ratio 81-83 5 speed. This is where the mystery begins.

This tranny has the filler plug on the driver side of it. So maybe it is from an 810/Maxima.

Further, the spacer between the front half/bell housing side and the tail shaft is made of aluminum not steel. Also,it has both a neutral switch and a back-up switch.

My buddy and I have done the test turning the input shaft 20 times and counting the revolutions of the tail shaft in each of the 5 gears. Granted, we didn’t have a degree wheel on the tail shaft, but the numbers we came up with are not close to matching up with any of the ratios that we have been able to find.

Here are the rotations and ratios that we came up with during our exploration.

1st 5.6 rotations ~ 3.63

2nd 8.8 rotations ~ 2.27

3rd 14.125 rotations ~ 1.41

4th ~1.00

5th 24.625 rotations ~ .812

I am liking the ratios with a good 1st gear for take off and also the overdriven 5th gear for highway.

But! What is this transmission from? I am definitely going to put it in the car, but curiosity has us wondering what it is and where we might get more of them or parts for repairs!

Any help would certainly be appreciated!

John

[LeonV]

Looks like you have either a 81-83 200SX or 74-80 620 Truck transmission, judging by the gear ratios. I'd guess 81-83 200SX based on the configuration of the transmission.

Source: gearing2

[EuroDat]

Aluminium adapter plate good indication its from a 200SX. I don't think the trucks had the aluminium adapters, but could be.

If its from the 200SX and thats stil the original bell housing, it will bolt up to a "L" series motor, but the transmission will be slanted 10degrees to the right and will cause problems with the rear transmission mount, gear stick in passengers seat, speedo cable hanging down low and and... The Z motor had the same bellhousing, but the motors were slanted to reduce height. Any 4 or 5 speed 71B bell housing will work.

Chas

Edited August 19, 2014 by EuroDat

[JR Ohio]

Thank you for the info EuroDat. The more info I have the better.

I just checked the transmission. The bell housing seems to be slightly tilted to the right like my Z motor and with that, it brings the shifter to the vertical position. So, if you are right, either the bell housing was changed at some point or the transmission is from 620 truck.

The chart that I have shows the same ratios for 81-83 200SX and 74-80 620 truck.

The aluminum spacer is the only one I have seen.

Anyone else that has any info to share would be appreciated.

John