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Someone Please Help Identify This Transmission


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Hello Ratsun!

 

I bought myself a 1972 Datsun 510 4-Door a few months ago and the seller included this transmission with the sale.

He knew absolutely nothing about it.

Can someone help identify this gearbox? Also let me know if it will fit my 510.

Here are some pictures.

 

 

 

 IMG_0578_zps20660170.jpg

 

IMG_0581_zps06ff7b77.jpg

 

IMG_0580_zps1d0854d5.jpg

 

IMG_0579_zpsdd7deb38.jpg

 

 

Thanks in advance for your help!

 

-Brodie

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Click the link here: http://dimequarterly.blogspot.com/p/back-issues-ordering.html

to find the DQ back issues. Then open Volume 11, Issue 4 for datzenmike's tranny id article. I'm thinking yours looks like Photo 11, the F4W71B 4-speed, but datzenmike needs to tell you what it really is. He can see all kinds of differences in bumps and ribs that I don't have a good eye for. I can tell you you don't have a dogleg 5-speed and that is about the limit of my tranny knowledge.

 

Len

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L series F4W71B as Len has stated. In this configuration it was only used in thew '71-'78 280z, one year only '79 280zx and the '74-'79 620. I have questions...

 

In this picture just forward of the shifter, below the 6 bolt cover plate (missing) is a hole? On some models there is a neutral switch here. Hard to tell if it's just missing or not. Can you look and see if the hole is threaded or is it just an empty casting boss?

IMG_0578_zps20660170.jpg

 

The F4W71B comes in two different gear sets, a wide and a mid ratio. This can be determined from the outside placing in first gear and by carefully turning the input shaft 20 times and counting the output turns. Perhaps a small dab of 'white out' at the 12 o'clock position on both input and output splines and have someone turn the input with some vice-grips while you count the output.

 

20 input turns = 5.56 or roughly 5.5 turns.......... is a 3.592 or wide ratio transmission

20 input turns = 6.02 or roughly 6 turns............. is a 3.321 or mid ratio transmission.

 

With or without the neutral switch and the gear ratio might improve the year or model or it might identify what it is NOT. Pretty sure it is NOT made after 1980 so not the later 280zx, the 810/Maxima or the 720 truck..

 

It's 31.5" long so will not fit your 510 without shortening the driveshaft and modifying the rear transmission mount. As you can tell, a mid ratio would most closely match your sedan's 4 speed ratio. 

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Wow! Lots of great information there. Thanks so much!

I checked the hole under the 6-bolt cover plate. It is threaded, so it is definitely missing that neutral switch.

This is very eye opening to me. I thought I may have scored a dogleg 5-speed with this sale! Oh well.

Sadly, this transmission will be of no use to me. Is it very well sought after? In good condition do you know what it would sell for?

Thanks again for your help!! Very very much appreciated.

 

-Brodie

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Vehicles with F4W71B 4 speeds with a neutral gear switch...

 

 

'72 to mid '75 model year 240/260/280z (no 280zx had this)

'78 and '79 620

 

The neutral gear switch really narrows it down. Only the '74 1/2 260z and the first year '75 280z 4 speed used the mid ratio gear box. All other years of z car and the two years of the 620 were a wide ratio. You could turn the input and count the out put turns if you wish to eliminate one or the other.

 

It's a much stronger transmission than a dogleg as it was used on the 6 cylinder z cars and the truck, but it is longer and only a 4 speed. I imagine that if someone has a z, zx, 620 or 810 4speed that needs a transmission, they would be looking for a 5 speed. It's a good transmission just not really desirable and not an upgrade.  $50-$100 maybe.

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