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Trans Swap on 521


jduarte

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Easiest is a dogleg 5 speed out of a 1977-79 Datsun 200SX, but I would not go that way for a couple of reasons, kinda expensive transmission and made for a car.

There is no cheapest way unless you have a buddy that you give you a 620 or 1980 720 5 speed, but then you need a custom drive line, I believe John521 figured out a way to use a 620 2 piece drive line in his 521.

I figured out how to make a short shaft 5 speed out of a 2wd 1985/86 regular cab/short box short shaft 5 speed with a 1980 Datsun 720 4/5 speed front case on it, but finding the parts is not easy or cheap, but the shift lever comes out of the stock shift lever hole, this is an article I wrote on how to do it.

http://community.ratsun.net/topic/28473-how-to-put-together-a-shortshaft-5-speed-for-a-l20b/

If you cannot see the photos you will need to install the "Photobucket embed fix" extension as Photolame screwed all the forums over.

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Thanks Wayno,

 

I'm trying to avoid so much swapping and staying out of the "u pick parts" places. I'm trying to keep it as simple as possible and John521's method almost sounds that way. There also seems to be a bit more parts available from the 620's & 720's currently, maybe he can chime in here soon. Do you know if a 1974 260Z 5spd trans would fit? 

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I guess I spelled his username wrong, it is "Jon521", but that really doesn't do a lot of good unless you sift thru years of posts to try and his thread as anything before the change to the forum in 2013 doesn't show up in his content, but I found his thread by searching his name on the internet, then picking an image of his truck since I know what it looked like, then going to that page(visit page), and then going to the first page and then I  copied the code in the search/results bar, I believe this link below will take you to his thread, his 5 spd conversion is somewhere in there.

http://community.ratsun.net/topic/32940-1971-521/page-1

Jon521 has not been logged in here since March 27, 2015 so i would not expect for him to chime in.

A longshaft 5 speed is a longshaft 5 speed, they have different gearing depending on what they came out of, the 260Z has a L block I believe, so that will bolt to any L block as far as I know, just remember that the clutch throw out bearing collar follows the clutch cover(pressure plate), so you should use the throw out bearing you are using in your 4 speed right now in the 5 speed transmission, the throw out bearing collar doesn't follow the transmission, it follows/stays with the clutch cover.

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Thanks Wayno,

 

I'm trying to avoid so much swapping and staying out of the "u pick parts" places. I'm trying to keep it as simple as possible and John521's method almost sounds that way. There also seems to be a bit more parts available from the 620's & 720's currently, maybe he can chime in here soon. Do you know if a 1974 260Z 5spd trans would fit?

 

You'll have to get your hands dirty at the pick and pulls at some time in your life.

 

 

Be on the hunt for a 2WD regular cab 720 to be able to do the Wayno 5speed swap. Wayne's method will keep you at 26" length. The dog leg will keep you at 26".

 

 

Any other 5 speed will be 31" and you will then be needing to modify drive lines.

 

 

As far as the Jon521 method- front drive line section from a later regular cab 620. The 620 went to 31" trans in 76? Maybe 75. I can't locate Jon521's thread about this. Maybe in his build thread.

 

 

You said you sifted through some threads. Keep going. There is no new info out and about about this. Use Google to search; include "Ratsun" in your search criteria.

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Cheapest 5 speed is likely the most plentiful one, the 71B. They are 31.5" long and will require the driveshaft to be shortened and the trans mount modified, but well worth it. Here's the vehicles that it came on that had L series engines which will allow it to bolt directly to your L16

 

'77-'79 620*  mid ratio gears with the '79 a wide ratio set

'80 720 2wd*  wide ratio gears

'77-'78 280z*  mid ratio gears

'79*-'83 non turbo 280zx  '79 was mid ratio all others were close ratio

'78-'80 810 mid ratio

'81-'84 Maxima, mid ratio

 

 

All these will work but you will be happiest with the Mid or the Wide ratio. If all you can find is a later 280zx that's fine.

 

Wide ratio...... very low first gear suitable for hauling heavy loads. Good take off acceleration.

Mid ratio........ best overall gearing for just about any vehicle.

Close ratio.... more effort taking off but overdrive is 2X what the mid ratio is and won't be much use unless on the highway. May need down shift on hills and into the wind.

 

* optional these years

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I can think of four L series 5 speeds that will work some with mods to the mount and driveshaft, and one requiring the tunnel to be widened, not counting any NISMO competition transmissions. Again the simplest is maybe the first gen dogleg but only available on one car for 3 years and an option on another so somewhat rare and for strength only adequate. The FS5W71B is a very strong six cylinder transmission also used in trucks, and much more common.

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Hello everyone,

 

So I went to go check out the trans I previously mentioned in an earlier post (1974 260Z 5spd trans), this is what the guy selling it claimed. He also claimed the car was a right hand drive. According to my research, a 4spd was sold on the 240/260/280Z's. The 5spd finally becoming an option on the 1977 280Z in the US and continuing through 83. There was one exception, a European 5spd available for the 240Z which was rarely seen in the US. I went through the gears and it was definitely a 5spd but I am not sure from what year. I deciphered a case# 7408086 and something else that says L2 on the side. I read a post on classiczcars.com forum which states "One muffler hanging tang + short shifter mount ears (~1" tall) = 79-81 280zx", the trans I saw has these details. The trans does not have a top access cover and looks like a "B" type since the shifter has a solid cross pin. According to gracieland.org, it is typical of 80-84 280ZX & 300ZX often called the "ZX" 5spd. According to zhome.com, it's from 77 through 83. Do the numbers I pulled have any meaning? Can anyone place the actual date on this?

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You can't always positively ID a trans but you can very often know what it isn't.

 

The B type all have the 'ears and a cross pin holding the shifter. This is what makes it a B.. the style of shifter.

 

Take a look at the speedometer sleeve attachment bolt. If on top it's made before '80 if at the bottom it's '80 or newer.

 

'79 and older had the bolt at the top. This is a '79 280zx 71B.

Zweu8Y9.jpg

 

'80 or newer.

EUZPLj7.jpg 

 

With an L series bolt pattern see my list (post #6) for what years and vehicles it was in.

 

If it only had a reverse lamp switch it's from a Z car, 810 or Maxima as they didn't need switches for pollution control because they were EFI vehicles.

 

Wayno my '78 620 didn't have the gussets and I replaced it with a '79 zx 5 speed. It didn't either.

 

You can narrow down further by identifying if wide, mid or close ratio IF the transmission is out. Place in first gear. Mark the input and output spline with crayon or chalk that is easy to see. Have someone turn the input spline exactly 20 times while you count the output turns.

 

Output turns

 

5.5....... WIDE

6.0....... MID

6.5....... CLOSE

 

Refer to my list on post #6 and you can further narrow down what it is out of.

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Thanks King Rat!

 

It looks like it's 79 and older since it has the bolt at the top.

I took picture like suggested. The links are below. Not sure how else to upload images on here. I'm not sure which the input and output splines are but the trans is out so I would love to check ratio

 

https://s20.postimg.org/ucp9yccsd/trans1.jpg

https://s20.postimg.org/qgby2czil/trans2.jpg

https://s20.postimg.org/jd42mr1st/trans3.jpg

https://s20.postimg.org/sxnp9myul/trans4.jpg

https://s20.postimg.org/mjym6e1od/trans5.jpg

https://s20.postimg.org/5jfpxq42l/trans6.jpg

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'77-'78 280z or perhaps a '79 280zx 5 speed.

 

Two things.... that's a 280z/zx rear transmission mount and it only has a reverse lamp switch because it's from an EFI car that didn't use them.

 

Although not definitive I have noticed the z and zx fill bungs are on the passenger side. (my 620 5 speed was on the driver's side) I also feel (as a rule) those gussets tend to be on the z car 5 speeds. My '78 620 didn't have them. 

 

This will make it a MID ratio gear set with a 3.321 first and a 13.6% overdrive.

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$600 would be... mmm.................... ok, I guess,..... if it was actually rebuilt and had a warranty.

 

The usual weak spot in these is the counter shaft bearing at the front about $9-15. Usually makes a lot of noise before there's serious trouble. On the earkly transmissions the mainshgaft nut would sometimes come loose and you would loose 5th. Later transmissions has a special nut that could be staked in place.

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  • 4 weeks later...

I'm interested in this thread since I've worked out most wrinkles in my '72 521 but  that poor 4 speed just doesn't cut the mustard on the freeway.

Don't like having to make than little engine work overtime to keep up. I'm not interested in the cheapest solution but the strongest most

reliable solution to get a 5 speed into the old girl. I'm not going to do the work myself but try to convince my favorite shop to do it. I know that's

probably silly but as much as I love driving the old 521 I've just reached a point where I don't like doing major of even less than major work on the truck.

I've sort of OD'ed on it after so many years.

 

Still I'd really like a 5-speed in the 521. So what's the optimal conversion. It seemed like it was a 5 speed with mid range gearing, a "dogleg" ( and here

I'm not sure of this reference to dogleg) transmission with possible cross member and driveshaft changes. What did I miss?

 

Jerry

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The dogleg refers to the S10 200sx 5 speed with a reverse above first shift pattern...

 

R..2..4

1..3..5

 

It's the same length as the 521 transmission so no driveshaft shortening but that's about it. It's a little light for a truck and you still have to mod the transmission mount. For that I would find an L series 71B 5 speed. The info is in this post.

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The one I have actually says ZL71B on the side.... I believe it's from the early 80s .. mine has the napz bellhousing so it tilts the wrong way and doesn't bolt down to the rear transmount.... thus the reason for the correct bellhousing.....

Oh and to do the swap I think you either need to swap the front bearing or have the case bored to accept the larger cluster bearing... I forget which way that goes... haven't opened mine up yet ... but I believe I have the part number somewhere for that bearing....

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All L series 71B 5 speeds were 31.5" long however there were some 26" 2wd ones on the 720 but I think only on the Z series engines. If they were available in L series just ignore the driveshaft shortening below.

 

A shortened driveshaft by the difference between the 5 and the 4 speed lengths... about 5.5"

Modified rear trans mount.

Use your 4 speed clutch release bearing and collar on the 5 speed clutch arm, though I would definitely replace the bearing.

 

I've done the same basic 4 to 5 speed on my 710 and the shorter speedometer cable will reach the further away position on the 5 speed by unclipping it from the body and running it down behind the head over the top of the transmission to the opposite side at the rear.

 

 

 

 

 


The one I have actually says ZL71B on the side.... I believe it's from the early 80s .. mine has the napz bellhousing so it tilts the wrong way and doesn't bolt down to the rear transmount.... thus the reason for the correct bellhousing.....
Oh and to do the swap I think you either need to swap the front bearing or have the case bored to accept the larger cluster bearing... I forget which way that goes... haven't opened mine up yet ... but I believe I have the part number somewhere for that bearing....

 

The larger 62mm front counter bearing was only on the '85 and up 71B so ... If you found a later Z series 71B and an L series front case to swap onto it, just pull the 62mm bearing off and press on a smaller 56mm that fits the L case.

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