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Identify my 5 speed


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My five speed has number 7426580 stamped in the top area of the bell housing. 

Mike can you identify it please. 71a, 71b or 71c? 

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Need a picture.

 

This shift pattern with reverse above first is an FS5W63A or dogleg, a very easy and common swap. Speedometer cable is on the left (driver's side)

R..2..4

N.N.N

1..3..5

 

A regular H pattern with 5th above reverse is likely a 71B or possibly a 71C. There are at least 2 other possibilities but unlikely.

 

 

 

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Not a dogleg. Not a short tail. 

Standard H pattern and speedo on right.

All apart now so tough for a picture. 

Wide ratio box.

Figured it would be easier for ordering parts if I could identify it as an A,B or C., depending on the parts guy I get and how receptive and knowledgeable he is. 

 

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How do you know it's a wide ratio?

 

Picture of the shifter area will differentiate an A from  B from a C

 

 

 

 

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 Definitely an FS5W71B made before 1980.

 

How did you find out it was a wide ratio box? 

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Research and reading. I read it on the Internet so it must be right :-). 

Multiple resources said the same thing about close ratio and wide ratio referencing the points I made above. 

Drove the car before removing for noise and it didn’t feel like a close ratio box. 

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Unless this transmission was built out of several other boxes there is only one year and one vehicle that had an L series wide ratio transmission.

 

At the very front of the case is the input shaft with a large gear behind the large bearing. For lack of a better term it is the counter drive gear. It meshes and drives another large gear directly below it on the counter shaft. Call it the counter driven gear. Count the gear teeth on these two and see if you get 21/32

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Ok so I’m confused.

Thought all 280Z with a five speed were wide ratio transmissions. Then later 280ZX we’re close ratio.  

If I’m reading what you’re saying correctly only one year and one vehicle was a wide ratio 5 speed meaning it was somewhat rare?

What are all the Z transmissions? Are the not considered a wide ratio?

 

The tooth count you referenced is 21/32 on my transmission. 

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Nissan uses basically 3 different ratio sets on their five speed 71B transmissions. I call them wide, mid and close. (there are racing transmissions that would be ultra close but for regular production vehicles basically three. A wide ratio first gear starts farther from the 1 to 1 forth gear compared to a close ratio transmission. A wide ratio has more mechanical advantage and torque multiplication so is good for use on a truck that has to start from stops with heavy loads. Also would be an advantage for a small displacement engine with less power. A close ratio first gear starts off closer to the 4th gear 1 to 1 and is good on a light vehicle or larger displacement engine with lots of power.

 

WIDE...... 3.592 1st gear '79 620, '80 2wd 720

 

MID......... 3.321 1st gear '75-'78 280z, '78-'84 810/Maxima, first year '79 280zx, '77-'78 620

 

CLOSE....3.062 1st gear '80-'83 non turbo280zx

 

 

21/32  is used on the wide ratio gear box. Could be an '80 720 2wd but you say the bolt is above the speedometer cable so '79 620. I have a close ratio box from a later '85 CA18ET in my 710. A 3.592 gives you a faster acceleration away from a start with a slightly heavier wagon. It's all good

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Well there you go, everyday is an education! 

Thank you for clarifying!

So between the wide and mid ratio transmissions how much difference in ratio are the other gears?

Pretty sure 4th would still be 1:1. What about 2nd, 3rd and 5th?

 

Is the B transmission the only one that used the fiber synchro for 5th?  Is that a completely different synchro assembly or can you substitute a brass synchro for the fiber. 

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Generally, but not all*, have the same 1, 2, 3 gears and the 21/32 combination at the front is what's used to spread them out. Using a 22/31 front gear combination closed them up to a mid ratio and a 23/29 produces a close ratio box.

 

*There is a later S12 71B that has a better 2nd gear that is slightly closer to 3rd and closes up the big RPM drop when shifting 2nd to 3rd.

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Might be reading to much into what your saying. Can the input shaft gear unit and driven gear on the countershaft be switched out to change from wide to mid to close ratio transmission?

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1 hour ago, datzenmike said:

Generally, but not all*, have the same 1, 2, 3 gears and the 21/32 combination at the front is what's used to spread them out. Using a 22/31 front gear combination closed them up to a mid ratio and a 23/29 produces a close ratio box.

 

*There is a later S12 71B that has a better 2nd gear that is slightly closer to 3rd and closes up the big RPM drop when shifting 2nd to 3rd.

 

 To recap, you can change the counter drive and the counter driven gears

 

21/32.... wide... 3.592 first

22/31.... mid..... 3.321

23/29... close.. 3.062

 

First gear is a combination of 14 teeth on the bottom counter shaft and 33 teeth on the upper main shaft 33/14 = 2.357

 

21/32 (wide) =1.523 X 2.357 = 3.5918 or rounded to 3.592

 

22/31 (mid) =1.409 x 2.357 = 3.321

 

(forgot)

The 280zx box uses a different gear set with 34 on the bottom and 14 on the top 34/14 = 2.429

 

23/29 (close) = 1.261 X 2.429 = 3.062  

 

If you are after a really insane close ratio transmission putting 23/29= 1.261 and 33/14 = 2.357  1.261 x 2.357 = 2.972 first gear!!!! This would be the same as starting from a stop in second gear in a mid ratio transmission.

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More education,Thanks

If you could find the input drive gear and counter driven gear to swap out could create different transmissions. 

Not going to be to feasible to find but does make for interesting reading and thinking. 

 

Counted the input drive gear on mine again. Actually is a 22 so it’s the mid ratio box. Shouldn’t count things like that early in the morning before coffee! 

 

Do you know the part number for the oil catch trough that’s in the steel mid plate?

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Oil gutter 32137-E9000

 

Some transmissions just catch splash and transfer it to the rear side of the adapter plate to flush oil forward. Maybe the newer ones? have a long gutter that runs into the rear of the case and is riveted to the side.

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10 hours ago, RLJ said:

More education,Thanks

If you could find the input drive gear and counter driven gear to swap out could create different transmissions. 

Not going to be to feasible to find but does make for interesting reading and thinking. 

 

Counted the input drive gear on mine again. Actually is a 22 so it’s the mid ratio box. Shouldn’t count things like that early in the morning before coffee! 

 

Do you know the part number for the oil catch trough that’s in the steel mid plate?

The gears and other rebuild parts are out there....

https://www.midwesttrans.com/nissan-fs5w71-5-speed-manual-transmissions/

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On 3/29/2021 at 12:12 PM, RLJ said:

 

 

Is the B transmission the only one that used the fiber synchro for 5th?  Is that a completely different synchro assembly or can you substitute a brass synchro for the fiber. 

 

I think the B were all brass synchro but some were steel 5th gear. I think my first year '79 280zx was so. If fiber ones were used it would be in the much later transmissions or GMs or something.

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9 hours ago, datzenmike said:

Oil gutter 32137-E9000

 

Some transmissions just catch splash and transfer it to the rear side of the adapter plate to flush oil forward. Maybe the newer ones? have a long gutter that runs into the rear of the case and is riveted to the side.

So some transmissions didn’t have the catch trough in the front of the steel plate? Thinking this feeds the rear trough. 

Mine has the riveted long trough in the tail section but nothing in the steel plate to feed the rear trough. Maybe there never was one in the front of the steel plate? Thought both troughs were to feed oil to the tail sleeve bearing for the driveshaft yoke. 

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 My info shows all 71B 4 speeds had the trough. Not until '79/'80 did it get added to the 5 speeds. There will be a hole above the rear trough if it did. Reverse and 5th will spin enough oil to keep the rear trough flowing. The front one promotes an exchange of oil through the adapter plate.

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24 minutes ago, datzenmike said:

 

I think the B were all brass synchro but some were steel 5th gear. I think my first year '79 280zx was so. If fiber ones were used it would be in the much later transmissions or GMs or something.

Looking at the aftermarket bearing and synchro kits for B transmission they don’t come with 5th gear synchro and some state it was a fiber synchro that is not included with the kit. 

Looking at mine it’s definitely not brass so thought it was fiber. I’ll have to check to see if it’s steel or fiber. 

Quite a learning curve on these transmissions particulars. Hopefully the bearing and synchro kit ordered is correct. 

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Pardon my French but, well shit you’re correct I ordered a 4 speed kit! Damn. 

Do you think the bearings and synchro rings will work in the 5 speed. 

The 5 speed kits showed 71A and 71C. Didn’t see a 71B kit for the 5speed and didn’t look close enough to see the 71B kit I was ordering was a 4 speed kit.  

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  • 3 weeks later...
On 3/31/2021 at 7:51 AM, RLJ said:

Looking at the aftermarket bearing and synchro kits for B transmission they don’t come with 5th gear synchro and some state it was a fiber synchro that is not included with the kit. 

Looking at mine it’s definitely not brass so thought it was fiber. I’ll have to check to see if it’s steel or fiber. 

Quite a learning curve on these transmissions particulars. Hopefully the bearing and synchro kit ordered is correct. 

 

My understanding is that there is one rebuild kit available from www.cobratransmission.com, for the three variations of the common 280Z/280ZX 5speeds.  You will see this in their listing of all the Nissan (Datsun) 5speeds..............same kit part #.  This kit comes with qty 5 brass synchro's.  The early .864 280Z/280ZX uses only qty 4 of the brass synchro's, as it uses a phenolic (fiber) 5th synchro, long NLA NLS.................but you can FLIP IT AROUND, as it is ambidextrous!  Both of the mid & late year 5speeds use the brass synchro on all five gears.

 

A quick VISUAL of the three common Z/ZX variants..........the early .864 5th has two forked ears at the bottom of the tail shaft.  The mid year .773 5th has one forked ear off to the drivers side with the speedo pinion bolt at 12 oclock.  The late .745 5th has one forked ear off to the drivers side, the speedo pinion bolt is at 6 oclock AND there is a 2 bolt "access plate" on the drivers side tail housing.

 

I do not believe that you can mix n match gears, to create what you want.  Sam Neave, down in one of the Carolina's, has a proprietary mix n match using some later 240SX KA 5speed gears, but requires machine work.  My understanding is that he created this mix n match for SCCA/vintage race applications, although I see no reason why you couldn't run on the street.............just NOT an economical option, as he is NOT cheap!!

 

I have heard of the oil trough & the big rear output shaft "dust shield", but I don't have those details in my notes!

 

Regardless, you should also buy the upper shift shaft seal & oring from Nissan..............not available in the aftermarket.  Removing that upper shift shaft can be a pain in the rear!  We learned to drill a ~~nickel sized hole in the tail housing (same place where the late 2 bolt access plate is) BEFORE attempting to remove the upper shift shaft "fork", which is held on by a taper pin, which is the big problem getting out without damage.  Drill the big hole, drive out the taper pin (use HEAT), tap the big hole with threads (yes, thick enough aluminum) & plug with a threaded plug & red locktite.

 

Hate to say, but I don't think the 4speed kit will work for you. 

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