Super 18 transfer case ?

I have a 1970 cj6 with a 225 Dauntless
Everyone tells me I have a super 18 transfer case. I guess it is a model 20 with the 18 parts inside.
So I want to rebuild it. (leaks all over) and have a few questions.
Will a regular kit work with it or does it have the exact same parts, larger parts or what?
does it use different gaskets?
Where do you get parts from someone who can tell me just what parts it needs?
Plus, does a twin stick kit work on the case?
I am at a bit of a loss here and would appreciate any knowledge on this case and how to identify if it is one or just a regular t18.

 

There are various versions of the 18 transfer case, different intermediate shaft sizes, etc.
Putting the guts and 18 output housings on a 20 case is not a new thing and is very common. The case is slightly stronger than a large hole 18 case, and all 20 cases use the larger 1 1/4" intermediate shaft which is the quietest, strongest, and longest lasting. You can put an 18 twin stick housing on the 20 case no problem, but must use the shift rails, shifters, etc.

I wouldn't call it a "super" 18 but is a little stronger than original. Tri-County Gear used to make a case girdle to increase the strength as well but not sure if they still do.

 

also before you get crazy. Its not a t18 its a dana or spicer 18. t-18 is a tranny. Iv been corrected before

 

So there is really no telling what I have till I open it up and start to take measurements?
OK then, where do I find parts for this project?

 

opps sorry, Just got this thing 4 months ago, I had a 65 cj 5 for years but little was stock on it. I really want to keep this stock as possible except about 2 inches of lift for some bigger tires.

 

Easy way to identify if it indeed is a 20 case is to look on the back. If a 20 case it will have two sheet metal "thimbles" or "cups" pressed into the case where the shift rails would protrude through the case when using 20 guts. The 18 cases have one protrusion that is cast as part of the case. You can also measure the intermediate shaft easily as it protrudes from both sides of the middle of the case and is held in place by a flat metal retainer and a bolt. There were 3 basic sizes of intermediate shaft, 3/4" which was used in MB, GPW, and very early 2a's, 1 1/8", and the largest and strongest which was 1 1/4". The latter used by all 20's and Dana 300's and later model 18's.

Regarding parts, look at the top of this section. There is a sticky post labeled "where to buy parts". I'd peruse that and look at the comments and experiences people have had. Many here use hermtheoverdriveguy (Herm Tilford), Novak Enterprises, Partsmike, R&P, and others. I'd highly recommend springing for the better (read hardened) intermediate shaft if yours is worn. Much more money but lasts about 10 times longer than the cheap ones.

 

Thanks nik
I will check them out.