Jump to content
Sign in to follow this  
locklock

Driveshaft Confusion - Hybrid Gearbox

Recommended Posts

lurch!

need help! my car was on 71a box previously.

I bought a rb20det 71c box and got everything sorted out. while mounting it back on, the shifter stick doesn't come out directly in the middle of the console.

Is there any way to fix this? don't really want to spend on another s14 gearbox if possible. my mechanic told me the tail shaft might not fit too.

Edited by locklock

Share this post


Link to post
Share on other sites

lurch!

need help! my car was on 71a box previously.

I bought a rb20det 71c box and got everything sorted out. while mounting it back on, the shifter stick doesn't come out directly in the middle of the console.

Is there any way to fix this? don't really want to spend on another s14 gearbox if possible. my mechanic told me the tail shaft might not fit too.

 

Well... you've made a mistake...

S13/14 is the gearbox you require.

NOT the RB20/RB30 unit - They are 50mm shorter.

 

If you want to keep that RB20 box, you'll need to cut the front of your trans tunnel away,

cut the front of your centre console away to allow the shifter to engage 1st, 3rd & 5th, and get a new tailshaft made.

Edited by Lurch ™

Share this post


Link to post
Share on other sites

Note to everyone else: the above is what happens when you don't do the research and/or ask the right questions!

Share this post


Link to post
Share on other sites

If you had the 71A box fitted before you've converted it to the 71C box, you'll need to have a new tailshaft made regardless,

as the 71a box has an output flange (as opposed to a slip yoke on the 71B/C box's) and a sliding spline centre section.

 

Personally, unless you installing a 250hp+ motor, I would have kept the 71A flange drive box...

Share this post


Link to post
Share on other sites

don't really feel like cutting the console. so with the s14 gearbox, what about the tailshaft?

Stock tailshaft will fit the rb 20/30 box.

Stick needs severe bending,,, after to piss off the rubber insulated standard RB stick, and graft a B stick on, or use an "S " shaped stick from one of the early utes.

Or,

Go S13/14, you'll need a shorter, by 50mm, tailshaft ( no, nothing fits, you need to get your stock one shortened), but, the stick comes up through tunnel hole just nicely, and you can retain the C type condom filled insulated stick.

Share this post


Link to post
Share on other sites

the original shaft is bolted to the end of 71a flange.

using the yoke with the the 71c, the both ends of the shaft is slotted in. do I need to weld either end?

post-104110-0-52183900-1509844936_thumb.jpg

post-104110-0-50619500-1509845297_thumb.jpeg

post-104110-0-22310400-1509845336_thumb.jpg

Share this post


Link to post
Share on other sites

I don't understand what you are asking...?

You could cut the old diff yoke off the 71A tailshaft, and use the 71C output yoke

and join them together with a NEW TUBE.

Edited by Lurch ™

Share this post


Link to post
Share on other sites

I don't understand what you are asking...?

You could cut the old diff yoke off the 71A tailshaft, and use the 71C output yoke

and join them together with a NEW TUBE.

yes I did that.

before the shaft was bolted on to the end of 71a. but now with the 71c is just a "tube" sticking into end 71c with no bolts.

picture for reference.

So both ends of my shaft is just sticking into the differential and 71c. nothing to bolt on.post-104110-0-34350900-1509847594_thumb.jpegpost-104110-0-34350900-1509847594_thumb.jpeg

Edited by locklock

Share this post


Link to post
Share on other sites

is there something wrong with this tail shaft?

this is what I gotten when removed. the flange is to 71a and the spline to differential.

post-104110-0-09406900-1509850288_thumb.jpg

Edited by locklock

Share this post


Link to post
Share on other sites

No picture in your post above, I'm eagerly awaiting one as I'm with Lurch and don't understand ? The tailshaft will have a uni joint on one end, with a flange that bolts to the diff. The other end is an internally splined yoke also with a uni joint. It has to have a splined slip joint somewhere to take up any misalignment / movement / etc.

 

Like this, front yoke may or may not have a dust shield depending what its off.

post-100293-0-59743500-1509850122_thumb.jpg

Share this post


Link to post
Share on other sites

Yes, there is something wrong with the tailshaft you posted. Throw all that splined section away - all you need from your existing tailshaft is the flange and uni joint on the diff end . Then take the front yoke and uni joint from the S13 / RB20 / whatever box you have. Then join them together with a solid tube of the correct length, get it balanced up and away you go. It then bolts onto the diff and slips into the rear of the gearbox on a splined slip joint.

Edited by 1600dave

Share this post


Link to post
Share on other sites

Just to be 100% clear, in the photo attached here, the bit circled in green comes from your existing tailshaft and bolts to the diff. The bit in red comes from the new gearbox. The tube joining them is new. 

post-100293-0-11910200-1509851796_thumb.jpg

Share this post


Link to post
Share on other sites

yes got it!

don't know what the previous owner did. the green circle was bolted to the 71a tail, and the red circle was just stucked into the differential.

Share this post


Link to post
Share on other sites

don't know what the previous owner did. the green circle was bolted to the 71a tail, and the red circle was just stucked into the differential.

 

AAEAAQAAAAAAAAw6AAAAJDhiNTM1ZDEzLTU5Yzct

Share this post


Link to post
Share on other sites

That’s intriguing, can you post a pic of how it was stuck into the differential?

sorry cozza, don't have pic taken. I believe it's 2 piece drive shaft.

Share this post


Link to post
Share on other sites

sorry cozza, don't have pic taken. I believe it's 2 piece drive shaft.

 

OK, I understand whats going on... Communication breakdown.

These posts need to be split from the main topic as well - it's gotten off topic.

Edited by Lurch ™

Share this post


Link to post
Share on other sites

If the S13 tailshaft bolts to your diff flange, that will work. You may still have to adjust it's length.

Share this post


Link to post
Share on other sites

S13 tailshaft flange may not bolt to a standard 240Z R180 differential flange.

You will need your original 240Z R180 tailshaft, ( the one that has the splined middle slip yoke and front flange), and have that rear flange fitted to the modified S13 tailshaft

Do not attempt to use the standard S13 two piece tailshaft, but have one made up, a single one piece tube, using the bits that do fit.

There are three versions of differential flanges, each has a different rectangular bolt pattern dimensions.

It gets a bit frustrating, but once you have it sorted out, it will work.

Edited by dat2kman

Share this post


Link to post
Share on other sites

The shaft in your 1st pic today doesn’t look original anyway, it seems to have 2 sliding yoke joints, 1 at the gearbox and the 2nd between the 2 parts of the shaft.

From my understanding an original 71a box would have had a flange connection at the gearbox just like at the diff not a sliding yoke joint.

Share this post


Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
Sign in to follow this  

×