Can someone tell me what model Datsun this trans is from?

[LadyZ]

Hi guys, maybe Datzenmike is the man to answer this, but I just picked this trans up to upgrade the 4spd one in my '76 280z. Is this trans from an 81-83 280zx maybe early 80s Maxima or is it a 720 truck trans? It looks like a close ratio 5spd from a 280zx but it has a gear oil fill plug on the left side. Let me know, Thanks for help

[datzenmike]

It's an FS5W71B built after '79 and from an L series engine. Not from a truck leaving only 280zx and 810/Maxima. If I had to choose I'd say 80-83 280zx non turbo. You want to know if 810/Maxim or 280zx???

 

Place in first gear, mark the input and output shafts. Have someone count the output turns while you turn the input exactly 20 times.

 

Output turns

 

5.5 turns is a Wide ratio truck transmission

6.0 turns is a Medium ratio transmission used on 810/Maximas.

6.5 turns is a Close ratio transmission used in the '80-'83 280z cars

 

 

[Bleach]

Aside from the oil fill location, it looks just like one I found in a 1982 280ZX.

 

[LadyZ]

3 hours ago, datzenmike said:

It's an FS5W71B built after '79 and from an L series engine. Not from a truck leaving only 280zx and 810/Maxima. If I had to choose I'd say 80-83 280zx non turbo. You want to know if 810/Maxim or 280zx???

 

Place in first gear, mark the input and output shafts. Have someone count the output turns while you turn the input exactly 20 times.

 

Output turns

 

5.5 turns is a Wide ratio truck transmission

6.0 turns is a Medium ratio transmission used on 810/Maximas.

6.5 turns is a Close ratio transmission used in the '80-'83 280z cars

 

 

Thanks very much Mike, I will have to count the rotations. Say it's an 810 Maxima trans, would you know the ratios of each gear? Or how they'd  compare to the ratios in a close ratio ZX trans? Thanks 

[LadyZ]

🙂

[yenpit]

This has the small oval 2 bolt access plate on the left side of the tail housing, so late 280ZX "close ratio".  However, I pulled a 5speed out of a low mile 1980 720 2WD L20B (first year 720, last year L20B) & it too has the oval 2 bolt plate!  I'm 98% confident it was original, as this truck only had 77k miles & was unmolested.  I have NOT done a rotational check to identify ratio..............

[datzenmike]

That's the reverse check sleeve that prevents a down shift from 5th directly into reverse. It on all 71B FS5W71B 5 speeds.

 

Mid ratio gears. L series five speed 620/810/Maxima/late 280z and first year ('79) 280zx 

 

1st...... 3.321

2nd.... 2.077... 37.5%

3rd.... 1.308.... 37%

4th.... 1.000.... 23.5%

5th.... 0.864... 13.6%

[LadyZ]

When I spin my input shaft 20 times, my output spins exactly 6 times, checked it twice. Mike I have 3 sources saying the 5th gear is .752 from 3 other sources. The first 4 gear ratios you listed are correct 👌 

[datzenmike]

The mid ratios never came with that over drive ratio. Your sources are wrong in two ways... it's not 0.752 either.

 

0.864 was only used in the '79 280zx optional mid ratio 5 speed the last year for the 4 speed

0.773 was used only in the '80 280sx non turbo close ratio 5 speed

0.745 was used only in the '81-'83 280zx non turbo close ratio 5 speed

 

The first 4 gears on the close ratio are

 

1st.... 3.062

2nd... 1.858

3rd.... 1.308

4th.... 1.000

 

 

I like the mid ratio much better. The close ratio over drive is too tall and won't get used much.

[LadyZ]

1 hour ago, datzenmike said:

The mid ratios never came with that over drive ratio. Your sources are wrong in two ways... it's not 0.752 either.

 

0.864 was only used in the '79 280zx optional mid ratio 5 speed the last year for the 4 speed

0.773 was used only in the '80 280sx non turbo close ratio 5 speed

0.745 was used only in the '81-'83 280zx non turbo close ratio 5 speed

 

The first 4 gears on the close ratio are

 

1st.... 3.062

2nd... 1.858

3rd.... 1.308

4th.... 1.000

 

 

I like the mid ratio much better. The close ratio over drive is too tall and won't get used much.

It's listed in the 1984 Maxima FSM Mike

[LadyZ]

https://linksharing.samsungcloud.com/qhGrJAdml0bC

[yenpit]

On 2/20/2023 at 5:52 PM, datzenmike said:

The mid ratios never came with that over drive ratio. Your sources are wrong in two ways... it's not 0.752 either.

 

0.864 was only used in the '79 280zx optional mid ratio 5 speed the last year for the 4 speed

0.773 was used only in the '80 280sx non turbo close ratio 5 speed

0.745 was used only in the '81-'83 280zx non turbo close ratio 5 speed

 

The first 4 gears on the close ratio are

 

1st.... 3.062

2nd... 1.858

3rd.... 1.308

4th.... 1.000

 

 

I like the mid ratio much better. The close ratio over drive is too tall and won't get used much.

 

Mike, I usually don't question you, but my understanding was that the "reverse lockout" (small oval 2 bolt plate access) was on the LAST of the ZX cars (81-83), thus .745 5th ratio, with the other four ratio's making it what many refer to as a "close ratio".  I can not see in these pics, but this trans should also have only a single forked ear on the left side bottom of the tail housing AND the speedo pinion bolt at 6 o'clock.  The .864 is the earliest & most common 5speed, with dual forked ears (one right, one left) and the speedo pinion bolt at 12 o'clock & referred to as a "wide ratio".

 

I would GUESS that ladyZ's "rotation" method (mistakenly?) showing .752 is closest to the .745, thus it is likely actually the late .745 "close ratio".........especially because it also has the small oval 2 bolt access plate for the reverse lockout.  Reboot?

 

I also kinda maybe might remember pulling a 5speed out of a late RWD Maxima, that also had the small oval 2 bolt access plate, as ladyZ posted above............

[datzenmike]

1980 is the pivotal year for the FS5W71B. The bolt that holds the speedometer pinion moved to 6 o'clock and the reverse check sleeve was added. ALL 5 speeds got this for '80 and on including wide/mid/close ratio. Even the 60 series transmissions on the 210 got the reverse check sleeve  

 

Earlier 4 and 5 speed speedometer pinions won't fit the '80 and newer transmissions. Well, if you use an angle grinder and cut a new key way 180 from the old one they will fit the newer transmissions. (usually)