I am putting a gsl-se rear end into my 81 gs. I was just wondering of all the mods I need to do? I will also be installing RB rear swaybar and springs with kyb gas-a-just shocks. If I can I will also be installing a 13b tranny and driveline. So what all do I need to do to get all these goodies installed?
Oh and how can I tell if a tranny is 12a or 13b?
Thanks all.
-r.

 

The only difference between the 1st gen 12A and 13B trannies is the 5th gear ratio. Its a little taller on the 13B, but both are identical otherwise. But as far as putting the SE rear into you 81, you'll need the driveshaft and the rest should just bolt up. The 81 driveshaft won't work with the SE diff as the pinion flange is a different size. You'll need any 84 to 85 driveshaft to make it work.

 

The 81 axles are smaller than the 84-85 so using the GSL-SE 3rd member wont work.

 

i would change the master cylender as well

 

As Wacky haas stated if you are just trying to install the center section (DIFF) it will not work.

I'm going to deduct that you are installing the rear end complete. If that is the case then yo use everything on the SE rear end including the E-brake cables.
As Viper stated you should also change the master cylinder as well.
As 85rotary powered pointed out you will need to use the driveshaft you have off of the Se.

 

also the proportioning valve.

 

Also, It hasnt been mentioned...but you do know the GSL-SE rear axles have a different bolt pattern than your '81 right?

And IIRC, the -SE tranny has an extra vent on the bellhousing that isnt present on the 12a tranny.

 

Wow, my first double post...
Sorry

 

YES THE WHOLE SE REAR END IS BEING SWAPPED. I WAS JUST WONDERING ABOUT THE THINGS LIKE THE MASTER CYLANDER, BRAKE LINES, DRIVELINE.
I DO HAVE A SET OF 14'S BUT THEY ARE OFF A 626.
THANKS GUYS. -r

 

JUST WANTED TO LET EVERYONE KNOW. I GOT THE SWAP DONE OVER THE WEEKEND. THE RB SUSPENTION FEELS VERY NICE. THE DIFF IS AMAZING AND IT STOPS REAL GOOD TOO. I JUST NEED TO FIND SOME NICE LOOKING 14' WHEELS FOR THE BACK. MY NEXT BIG MOD IS A WEBBER 48IDA. I WILL EVENTUALLY GO STREETPORT TOO.
-r

 

Do you need to shout?

 

some people don't know how to type with the caps lock off

 

sorry...

 

NP, I find caps much harder to read.