• Welcome to the new NAXJA Forum! If your password does not work, please use "Forgot your password?" link on the log-in page. Please feel free to reach out to [email protected] if we can provide any assistance.

Can I make a 21 spline work with a 23 spline T case???

vwJarhead

vwJarhead

NAXJA Forum User
Location
Westminster, Maryland
OK, so I got a line on some great parts recently one of which is a rear D44 built axle and the Tcase with Hack n Tap and drive shaft to run it. But, it is a 23 spline and my trans to Tcase may be 21 spline because it is a 1990. Now, if this is the case and I want to use the parts how do I make it work? This may be a dumb question but I didn't grow up with a wrench in my hand...Any help would be great as a fix would save me from needing a new shaft and a new hack n tap or SYE.
 
Take both cases apart. Put the hack and tap output shaft into your 21 spline case, and reassemble it.


The 231 is about the easiest case in the world to rebuild, I think it has 4 moving parts. Its ultra simple once you crack it open.
 
cal said:
Take both cases apart. Put the hack and tap output shaft into your 21 spline case, and reassemble it.


The 231 is about the easiest case in the world to rebuild, I think it has 4 moving parts. Its ultra simple once you crack it open.
Click to expand...
OK, so having never taken a case apart and being mechanically novice...can I assume then that you are saying that I can modify my case to accept the others output shaft and plate? So then the input from the trans to the Tcase will still be 21 spline and the output to the drive shaft will now be 23 spline? Again not having experience with the internals, wouldn't that jack up the function? Or does the tooth count of the shaft have nothing to do with the internal drive gears? Sorry, but I want to be sure this will work. Thanks.
 
depending on how good of a deal your getting on the transfercase, it may be cheaper to do a porc hd sye(under $200) and use a front shaft.
 
89xj said:
depending on how good of a deal your getting on the transfercase, it may be cheaper to do a porc hd sye(under $200) and use a front shaft.
Click to expand...



Except that porc will probably never ship the parts, never refund the card, and the front shaft will probably end up with bad vibes or being too short.

That was, IMHO, the worst advice I've seen all day. ;)
 
I was a'scared of my t-case the first time I split it too, it really is pretty simple in there. Split 'em side by side and swap the parts over.
 
Or just cut your shaft and install the seal and yoke on your t-case(dis-asembly not required)!
 
cal said:
Except that porc will probably never ship the parts, never refund the card, and the front shaft will probably end up with bad vibes or being too short.

That was, IMHO, the worst advice I've seen all day. ;)
Click to expand...

sorry, do the same but with a advanced adapter hd sye
 
I think I follow you guys...Anybody have a link to a schematic or overview of the process of switching the parts over?
 
Are both cases either 231 or 242. You cannot swap the shaft from a 231 into a 242 or the other way around.

The 90 model case will also need the seal to keep the fluid in.
 
Jess said:
Are both cases either 231 or 242. You cannot swap the shaft from a 231 into a 242 or the other way around.

The 90 model case will also need the seal to keep the fluid in.
Click to expand...
Both are 231 autos but the one with 21 spline is the 90. The one with the 23 spline is the one I want to use and it is from a 93.
 
apparently the input is separate from output shaft, which makes sense if the low range uses planetary reduction gears... you should be able to just install your input shaft/bearings/retainer into the other 231 and be off... I think...
 
Mr_Random said:
apparently the input is separate from output shaft, which makes sense if the low range uses planetary reduction gears... you should be able to just install your input shaft/bearings/retainer into the other 231 and be off... I think...
Click to expand...
Only one way to find out...sound like it will work though. Thanks everyone for your help and info.
 
Well it looks like I am screwed then...because the new Tcase is from a 96. I thought it was a 93....
 
You must log in or register to reply here.

Similar threads

O
SYE vs Fixed Yoke spline geometry
Replies
7
Views
3K
RCP Phx
R
W
Newbie with an XJ
Replies
8
Views
174
RCP Phx
R
M
NP 231 input shaft
Replies
3
Views
2K
RCP Phx
R
S
1990 xj 4.0 242 Hack n Tap question
Replies
12
Views
2K
sjx40250
S
Root Moose
Mild Lifting with OEM Parts
Replies
12
Views
1K
Tim_MN
Tim_MN
Back
Top