Jump to content

521 Transmission Swap


richw41

Recommended Posts

I have read through many of the posts regarding swapping a 4 speed to 5 speed. Some posts say the swap is direct no change with short 200sx(78?ish) 4 speed with overdrive. I have read others that say there is a mounting plate that needs to be shortened. Can someone tell me if they did this? Thanks!

  • Like 1
Link to comment
  • Replies 43
  • Created
  • Last Reply

Top Posters In This Topic

Top Posters In This Topic

There is no direct swap to a 5-speed in a 521. At a minimum you need to mod the crossmember where the rear mount goes. The trans LENGTH of a short-tail dogleg is the same as the stock trans, which makes it easier than using the larger, longer standard-pattern 5-speed.

 

You also have to decide how you will deal with the different output type- weld up or plug the bolt hole in the original 521 flange, or have the driveshaft modified to use a slip yoke.

  • Like 1
Link to comment

There is no direct swap to a 5-speed in a 521. At a minimum you need to mod the crossmember where the rear mount goes. The trans LENGTH of a short-tail dogleg is the same as the stock trans, which makes it easier than using the larger, longer standard-pattern 5-speed.

 

You also have to decide how you will deal with the different output type- weld up or plug the bolt hole in the original 521 flange, or have the driveshaft modified to use a slip yoke.

  • Like 1
Link to comment

Is there any info already available that shows these mods? What is a slip yoke?

 

A slip yoke is the female part of the driveshaft~ it's smooth -n- round on the outside in all the right places, and strategically placed bumps -n- valleys (splines) on the inside. These engage the output shaft (the male part) with corresponding bumps-n-valleys (more splines) that, when properly sized, make the world go round via the driveshaft. It allows fore/aft movement during suspension travel...:cool:

 

I have a nearly complete 5-speed setup never used on my 521, if you're interested....

  • Like 3
Link to comment

 

 

:lol: :lol: I guess it is easy when you know how, seems hard though when you've never done it before, you make mistakes, realize it won't work, tear apart what you made and do it again till it works, I do shit like that all the time, but that is half the fun of owning a datsun. I am still working on the easy part of my LZ23, i'll get it one of these days.

  • Like 1
Link to comment

I have read through many of the posts regarding swapping a 4 speed to 5 speed. Some posts say the swap is direct no change with short 200sx(78?ish) 4 speed with overdrive. I have read others that say there is a mounting plate that needs to be shortened. Can someone tell me if they did this? Thanks!

 

As Doug said the 200sx dogleg 5 speed is the right length so that the driveshaft does not need shortening but you do have to do some very minor work on it. The shifter should closely fit in the same hole in the tunnel too. The rear transmission mount does need to be modified.

 

Clutch

 

The dogleg will fit and is a good match for the smaller L16 in a 521. You don't mention how complete the dogleg is. Does it have the clutch arm, the slave cylinder and pushrod the works it and is there a throwout bearing and sleeve on the end of the clutch arm?

 

trannyforkBtypeLarge.jpg

 

If your new dogleg has the slave, pushrod, clutch arm, and release bearing collar all you need is to replace the release bearing with a new one and you are good to go. Let me know if not.

 

 

The Driveshaft:

 

The 521 driveshaft has a spline that is bolted into the end of the transmission. This spline has a flange that allows it to be bolted to the rest of the driveshaft. Here is a 521 transmission with the flange output spline. The large nut attaches it to the mainshaft of the transmission. The four holes on the flange are to bolt it to the rest of the driveshaft.

 

transF4W63520-521flangeo-p.jpg

 

Remove the nut and the spline slides out and can be used on the dogleg. The dogleg does not need the nut but the hole covered by the nut will leak oil so it needs to be plugged. Here is the dogleg (below) with the 521 flanged spline installed. The spline has been sealed with a 40mm frost plug. (or whatever works for you) Now the transmission can be installed and the rest of the driveshaft just bolts on.

 

521flangeonnonflangeF4W63needsplug.jpg

 

 

Transmission Mount:

 

The 521 mount can be modified and used. I don't have the exact measurements but once the dogleg is in you should be able to measure it much closer. This is the area to be removed and welded back up.

 

F4W63toFS5W71Btransmount.jpg

 

Modified mount facing the other way.

 

doglegmountfor521001.jpg

 

 

 

 

.

  • Like 2
Link to comment

if you use a long tail 5 speed, you can use a 620 front shaft instead of the 521 front shaft and it is essentially a bolt up job..

 

you still need to mod the tranny mount, plus make a spacer plate to move the driveshaft center bushing one inch forward, but no need to have the driveshaft shortened and have a splined yoke mounted. i did it this way as i had a donor 620 wreck.

 

the dogleg is an easier swap, but there is debate that they are a weaker tranny and they are definitely harder to find.

  • Like 2
Link to comment

i took 3/4 of an inch out, but you have to take the section out wher the lines are... i originally cut it at the tranny mount side and you end up with clearance issues with the top half of the tranny mount.

  • Like 1
Link to comment

:lol: :lol: I guess it is easy when you know how, seems hard though when you've never done it before, you make mistakes, realize it won't work, tear apart what you made and do it again till it works, I do shit like that all the time, but that is half the fun of owning a datsun. I am still working on the easy part of my LZ23, i'll get it one of these days.

 

haha thats true! i did mock it up and then tear it all apart again.

 

 

 

this is the setup i followed

 

Here the transmission mount for a long shaft 5 speed in my 521. The truck has a L-18 engine in it.

TransMount2.jpg

And this is the other side of it.

TransMount1.jpg

This is a picture of the yoke I used with the 5 speed.

TransYoke1.jpg

The second picture of the yoke.

TransYoke2.jpg

 

The part of the mount that bolts to the cross member is just a "L" shaped piece of steel, and it has a short piece of rectangular tube welded to it.

Part of the original Datsun trans mount was cut out so it could slide forward and back on the rectangular tube, and before it was welded together, the mount was bolted to the transmission, and lowered on the pieces, and tack welded. Then it was removed, and welded together.

 

 

this is how it turned out.

heres the mount in place

DSC03416.jpg

 

 

this way i think is the best, and most of the fabing can be done before hand. i also used a 620 front driveline

  • Like 1
Link to comment

A slip yoke is the female part of the driveshaft~ it's smooth -n- round on the outside in all the right places, and strategically placed bumps -n- valleys (splines) on the inside. These engage the output shaft (the male part) with corresponding bumps-n-valleys (more splines) that, when properly sized, make the world go round via the driveshaft. It allows fore/aft movement during suspension travel...:cool:

 

I have a nearly complete 5-speed setup never used on my 521, if you're interested....

  • Like 1
Link to comment

A slip yoke is the female part of the driveshaft~ it's smooth -n- round on the outside in all the right places, and strategically placed bumps -n- valleys (splines) on the inside. These engage the output shaft (the male part) with corresponding bumps-n-valleys (more splines) that, when properly sized, make the world go round via the driveshaft. It allows fore/aft movement during penetration...:cool:

 

 

fixed...

  • Like 1
Link to comment
  • 2 years later...

This thread was fucking useless!

 

There's lots of good info for two styles of 5 speed swaps. What do you need?

 

 

There is no direct swap to a 5-speed in a 521. At a minimum you need to mod the crossmember where the rear mount goes. The trans LENGTH of a short-tail dogleg is the same as the stock trans, which makes it easier than using the larger, longer standard-pattern 5-speed.

 

You also have to decide how you will deal with the different output type- weld up or plug the bolt hole in the original 521 flange, or have the driveshaft modified to use a slip yoke.

 

 

 

 

As Doug said the 200sx dogleg 5 speed is the right length so that the driveshaft does not need shortening but you do have to do some very minor work on it. The shifter should closely fit in the same hole in the tunnel too. The rear transmission mount does need to be modified.

 

Clutch

 

The dogleg will fit and is a good match for the smaller L16 in a 521. You don't mention how complete the dogleg is. Does it have the clutch arm, the slave cylinder and pushrod the works it and is there a throwout bearing and sleeve on the end of the clutch arm?

 

trannyforkBtypeLarge.jpg

 

If your new dogleg has the slave, pushrod, clutch arm, and release bearing collar all you need is to replace the release bearing with a new one and you are good to go. Let me know if not.

 

 

The Driveshaft:

 

The 521 driveshaft has a spline that is bolted into the end of the transmission. This spline has a flange that allows it to be bolted to the rest of the driveshaft. Here is a 521 transmission with the flange output spline. The large nut attaches it to the mainshaft of the transmission. The four holes on the flange are to bolt it to the rest of the driveshaft.

 

transF4W63520-521flangeo-p.jpg

 

Remove the nut and the spline slides out and can be used on the dogleg. The dogleg does not need the nut but the hole covered by the nut will leak oil so it needs to be plugged. Here is the dogleg (below) with the 521 flanged spline installed. The spline has been sealed with a 40mm frost plug. (or whatever works for you) Now the transmission can be installed and the rest of the driveshaft just bolts on.

 

521flangeonnonflangeF4W63needsplug.jpg

 

 

Transmission Mount:

 

The 521 mount can be modified and used. I don't have the exact measurements but once the dogleg is in you should be able to measure it much closer. This is the area to be removed and welded back up.

 

F4W63toFS5W71Btransmount.jpg

 

Modified mount facing the other way.

 

doglegmountfor521001.jpg

 

 

 

 

.

 

 

if you use a long tail 5 speed, you can use a 620 front shaft instead of the 521 front shaft and it is essentially a bolt up job..

 

you still need to mod the tranny mount, plus make a spacer plate to move the driveshaft center bushing one inch forward, but no need to have the driveshaft shortened and have a splined yoke mounted. i did it this way as i had a donor 620 wreck.

 

the dogleg is an easier swap, but there is debate that they are a weaker tranny and they are definitely harder to find.

 

 

haha thats true! i did mock it up and then tear it all apart again.

 

 

 

this is the setup i followed

 

 

 

 

this is how it turned out.

 

 

 

this way i think is the best, and most of the fabing can be done before hand. i also used a 620 front driveline

 
  • Like 1
Link to comment

Nobody said

 

Correct amount to cut of or correct length of bracket.

 

no one mentioned throw out bearing collars

causing issues if the dogleg was pulled from l20b

 

clutch fork as well as how much to lower the mount cause it hits the top of trans tunnel. Also shifter needed to be heated to be bent. And for that the little bushing needs to be taken off with a high chance of breaking so buy a new one at dealer before hand.

there are so many little things.

 

All to take into consideration

 

Sorry i was just pissed took me three days for the swap as well as taking the engine out 3 times

  • Like 2
Link to comment

Nobody said

 

Correct amount to cut of or correct length of bracket.

This is more or less a custom fit thing. Don't forget this was never in the 521 so better that you install and make your own. What works for A may not be exact for B.

 

no one mentioned throw out bearing collars

causing issues if the dogleg was pulled from l20b

The release bearing collar is sized to match the clutch not the engine. All L20B doglegs were car engines and fitted with a 200mm clutch.. the same as that used in the 521, even though it is an L16. The collar should remain with the clutch it is used with.

 

clutch fork as well as how much to lower the mount cause it hits the top of trans tunnel. Also shifter needed to be heated to be bent. And for that the little bushing needs to be taken off with a high chance of breaking so buy a new one at dealer before hand.

there are so many little things.

You can use the 521 clutch arm or fork, it has the threaded rod adjustment. Again the mount is a fit and measure thing. Ideally the driveshaft must remain in the same position to keep the U joints happy. I've bent lots of shifters without heating by placing in a vice and using a length of pipe over the end. I hear ya on the little things.

  • Like 2
Link to comment

If the collar was a problem maybe the L20B was previously in a truck, which would have had a 225mm clutch. I put a car L20B in my 521 and used the L16 200mm throw out collar.... worked just fine. L16s and car L20B use a 200mm clutch.

  • Like 2
Link to comment

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

Loading...
×
×
  • Create New...

Important Information

By using this site, you agree to our Terms of Use.