Jump to content
Als720

Transmission swap

Recommended Posts

Im wondering how much modification it will take to install a long tail transmission on my single cab wich comes with a short tail. Any info will be helpful before i start taking it apart.

  • Like 1

Share this post


Link to post

Just remember longer transmission will require shorter rear drive shaft components.

  • Like 1

Share this post


Link to post

What's the reason for wanting to swap?

What's the current motor trans combo?

 

I just installed a short tail from a 720 into my 521, learned a bit about the 71b transmission... it seems like the mount location is the same, so the only difference should be the driveshaft length and shifter location.... 

 

 

 

 

  • Like 1

Share this post


Link to post

Yes the only real difference is driveshaft length and possibly needing a longer Speedo cable.

 

The shifter will be in a different position, but the 720 shifter plate should just turn around to accurate accommodate that.  If you have a center console, that is different from long to short as well, due to the changed shifter position.

 

If you are abandoning the short trans, and you are 2wd, i would be interested in buying the tail housing from you.

  • Like 1

Share this post


Link to post

The reason im swapin is because mine jumps out of 1st and i bought one but they sent me the wrong one, im getting the front part of the drive shaft as well as another shifter from them 

 

i was looking at them and the speedo cable does seem to be on the other side migh need to find one thats longer

 

as to the shifter hole would it be a lot of cutting? Or what do you mean by the shifter plate?

  • Like 1

Share this post


Link to post
2 hours ago, Als720 said:

The reason im swapin is because mine jumps out of 1st and i bought one but they sent me the wrong one, im getting the front part of the drive shaft as well as another shifter from them 

 

i was looking at them and the speedo cable does seem to be on the other side migh need to find one thats longer

 

as to the shifter hole would it be a lot of cutting? Or what do you mean by the shifter plate?

I think there is about a 4 inch difference... I think what lockleaf is saying is the cover that bolts to the tunnel should hopefully have the hole offset to the front.... if your lucky you can flip it 180 and have the hole where you need it....

To bad they couldnt send the right one instead.... 

So are you completely committed to this?  

Popping out of gear could be as simple as low oil, or bad syncros.. alot of the internal parts can be sourced, and you can get rebuild kits for these with bearings and syncros for about $125 plus the labor.. I did mine myself, it was first transmission, its challenging but not impossible was actually easier than I though it would be,  pics and organization is the key,....

i'm just saying.....

If not send to lockleaf dont just scrap it... 

  • Thanks 1

Share this post


Link to post

There are a few things you need to understand/consider, the shift lever you shift the gears with will be 5 inches father back, is there 5 inches of room between your shift lever you have now and the seat in 2nd, 4th, and reverse, if not this transmission will not work for you.

The plate referred to is the plate that screws onto the tunnel that has the hole in it that your shift lever comes thru now, I do not believe this plate is reversible, but the place you got the transmission from might have the plate you need, otherwise you will have to make a new hole in your plate and fill the one in it now.

I do not believe that the regular cab/short box 1985 Nissan 720 ever came with a long shaft, but maybe the earlier 1981/82/83 had the drive line you can use, I do not know for sure.

Do you have the console with the oil pressure and volt gauges, if you do you will either have to re-position this or get the proper console.

Have you ever removed the transmission in this truck before, or any other vehicle for that matter, there are things you need to know, if the transmission came out of an 81/82 Datsun 720 and the clutch arm and throwout bearing are in the transmission, you cannot use that throwout bearing as it is for a 225mm clutch cover, you need to use the throwout bearing you have right now in your transmission as it is for your 240mm clutch cover on your flywheel.

You need to measure how much room you have between the shift lever and your bench seat, make sure you even have the room, if you have bucket seats then that is not an issue.

 

This seems like a hole being dug into the ground, the longer it goes on, the deeper the hole gets, the harder it is to get out of the hole.

  • Thanks 1

Share this post


Link to post

Im going to do some measuring and see the space im going to end up with between the seat and were the gears will end up.

They are sending me what they said will fit hopefully thats right if a decide its worth to go that way, i might try to rebuild it 

i have removed some transmissions and a couple headgaskets on the z24 as well as on an iron duke from an s10 i think with some help i can rebuild it i have checked the oil and put new in it but it seems like a syncro the plug was stripped from the past owners and it seems it was never serviced properly all of its 154k miles

im going to check with them on what year truck  the transmission is either way i was planning on a new clutch kit. 

 

It does seem like a whole being dug.. was hoping for only taking it off and putting the replacement on and getting to drive it already but if its too much of a hassale ill have to figure out something better to do

Share this post


Link to post

Is this your only vehicle?

Hopefully not.....

Personally I would pull your transmission out and have a look inside....

The front and rear cases are easily removed and you end up with this....

 

20190108_153736.jpg

 

If it's already broken why not have a look, even if your not confident on the rebuild part,  bringing the trans in like that should atleast save some money....

 

There is some good pics and stuff in my 521 build thread, last few pages have the pics and info.. also Daniel 

With his ratsun or dragon 521 posted a bunch of pics, he just split his long tail before installing, same process just...

  • Like 2

Share this post


Link to post

Waynos point about the bench is a good one.  There is always the possibility the shifter could be bent into a new shape to work around that or get real hardcore and weld up a sweet custom shift lever out of a length of chain.

 

And seriously, if you are not keeping that short tail trans and its 2wd, i would really be interested in that tail housing.  If it's 4wd, but has the speedo hole, I'm still interested.

Share this post


Link to post

If 4x4, the hole is cast but it's not drilled through and machined out for the speedometer sleeve

 

CKtGxyX.jpg

Share this post


Link to post
On 2/1/2019 at 4:26 AM, Crashtd420 said:

Is this your only vehicle?

Hopefully not.....

Personally I would pull your transmission out and have a look inside....

The front and rear cases are easily removed and you end up with this....

 

20190108_153736.jpg

 

If it's already broken why not have a look, even if your not confident on the rebuild part,  bringing the trans in like that should atleast save some money....

 

There is some good pics and stuff in my 521 build thread, last few pages have the pics and info.. also Daniel 

With his ratsun or dragon 521 posted a bunch of pics, he just split his long tail before installing, same process just...

So you learned something on your last foray, eh? The student becomes the teacher...

 

It's not that much more work to take something to 100%, especially when it's already on your workbench.

Edited by Stoffregen Motorsports
  • Like 2

Share this post


Link to post
1 hour ago, Stoffregen Motorsports said:

So you learned something on your last foray, eh? The student becomes the teacher...

 

It's not that much more work to take something to 100%, especially when it's already on your workbench.

 

 

If I can do it others should be able to, I like passing on what I learn...

Plus I figure that's the whole reason for this forum.... 

If it wasnt for datsunmike I would have sold my stumpy 5spd, but because of everyone here i learned alot and got the confidence to do a rebuild and a bellhousing swap.. now i have a great 5spd behind my L16....

 

 

  • Like 3

Share this post


Link to post
On 2/3/2019 at 10:55 AM, Crashtd420 said:

 

Plus I figure that's the whole reason for this forum.... 

 

 

 

That is the primary reason forums exist. Lots of people forget that.

  • Like 1

Share this post


Link to post

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.