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Syncro difference btw closer ratio and wider ratio FS5W71B


tamo3

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I'm currently rebuilding FS5W71B closer ratio transmission.

I have several wider ration transmission, and I bought a rebuild kit for wider ratio by mistake.

This kit include 4 syncros those are same size.

post-25175-0-38595300-1369334286_thumb.jpg

 

When I pull tranny a parts, I realized that 1st and 2nd gear syncro is different shape.

post-25175-0-14900900-1369334303_thumb.jpg

 

I went to Nissan Dear in San Jose and ask for '82 280ZX syncros and the dear gave me part # 32604-P0100 (RING-BAULK) and he maintained I need  4 of them.

 

Searching web site,

http://www.carpartsmanual.com/datsunS30/DatsunZIndex/PowerTrain/TransmissionGears/5Speed/tabid/1708/Default.aspx

post-25175-0-18580400-1369334503_thumb.jpg

This site mentioned I need 5 of #45.

 

I'm totally confused.

Does anyone know what is the correct parts number for closer ratio FS5W71B syncros for 1st and 2nd gears?

 

Thanks,

tamo3

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I just rebuilt several 280ZX FS5W71B from 1982 and 1983 models.

In the later trannys rings 1-4 are interchangeable.  #5 is a smaller size.

Your close-ratio doesn't look like mine.  Count the teeth on that 1st gear and counter gear?

 

Its been years since I have had a 1977 apart and don't remember.

 

In the website picture I think the 5th gear is part number 33, 35,37 one of those is the 5th gear synchro.

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PS... having done about 6 trannys this year, you will find disappointment in all the rebuild kits.

Check fitment before removing seals and stuff.  Half the stuff they send doesn't fit when I use the kits.

 

You can also measure the dimension per the FSM and maybe your synchro is just fine and can be re-used if NLA.

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Thanks duragg for quick reply and advice. I will count the gear tooth and measure the dimmention and check FSM when I get home.

 

Looks like FS5W71B closer ratio CA model is similar to FS5W71C.

http://720world.com/forum/topics/how-to-remove-front-case-from?xg_source=activity

 

"Here's my B type from the CA motor: Note that it also has the larger C type forks and thinner 1st/2nd synchro."
 

trannyLarge.jpg

 

Compare 71B vs 71C

http://zhome.com/ZCMnL/tech/240SX5spd/Transmission2.htm

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So what's it from?

Definitely didn't look like an 83.

 

If you can post the counter gear teeth counts I can compute all the ratios and make an image of the speeds / gears.

Reference a previous thread I started just a few weeks ago.

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This tranny got from one of member in this forum. He kept bell house for 240SX 71C conversion.

I thought this tranny is from 280ZX, but now I'm not sure.

 

I count counter gear teeth.

Counter drive gear = 32

1st  = 14

2nd = 20

3rd = 28

5th = 45

Reverse = 15

 

I couldn't find other duragg's thread about the calculation gear ratio from gear teeth. I thought you posted WTB section for 5th gear...

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Found the thread.

http://forums.hybridz.org/topic/112772-tranny-gears-wanted-discussion-ratios-gear-swaps/?p=1056030

 

After calculate gear ratio...

 

post-25175-0-40190800-1369418264_thumb.png

 

1st = 3.591

2nd = 2.057

3rd = 1.360

4th = 1.000

5th = 0.812

Reverse = 3.657

 

I'm wondering whether it worth to rebuild this tranny... 1st and 2nd gear is wider than '77 tranny....

Edited by tamo3
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Isn't the truck transmission shorter?  Maybe the 200SX also.  Might be good to measure.

 

I've seen those synchro differences and I was under the impression that it's just a different design for the same function.  The critical dimensions are probably the same, just some teeth missing on one.

 

 

Edit - actually they might be shorter than the 240SX 71C, but similar or the same as the 280Z 71B. 

Edited by NewZed
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Yep, the 200SX box needs the rear mount moved, but the driveshaft can stay the same length when doing a FS5W71C conversion for the Z cars.

 

Looks like the rings for 1-2 are bigger than 3-4. 2nd gear is a single-cone synchroniser, making it a Post-83, Pre-86.5. With that gear spread, I'm with Leon...it's a 1984 200SX box.

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Thanks NewZed, Xnke, and Leon for your feedback.

I just measure the size last night and find out the unkown transmission is shorter than 71B. NewZed is right!

post-25175-0-07016300-1369845138_thumb.jpg

post-25175-0-91183400-1369845144_thumb.jpgpost-25175-0-90451000-1369845149_thumb.jpg

 

As Xnle mentioned, the syncro ring for 1-2 is bigger than 3-4 as Xnle mentioned.

 

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I actually thought it would be more than 5/16", between 1 and 2 inches (recalled from one of Xnke's previous threads, I think).  And I think that measuring to the end of the output shaft might be more important, although the dust shield matters too.

 

Have you compared bellhousings (front cases)?  I'm not familiar with the CA20 engine (Leon's link), it may not have the same tilt/angle and bolt pattern as the L engine.  You might be in to a bellhousing swap, with machining and/or bearing swaps required.

 

Whatever it is you're working with doesn't seem to be a common transmission used for the Z's.

Edited by NewZed
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