Dana 18 T-case help

I have an old '63 FC-170 that I bought all complete and was told it ran and drove until "something about the transfer case broke". I got her home and surveyed the scene closer and saw that the inner shift rail had broken in half. This particular set up in the FC has a single shift lever that comes back to a plate that attaches and shifts both shift rails, just like the single shift Dana 18s in early 70s jeeps. I pulled the case off the T-90 and checked even closer and found that once I pulled the yoke and the front bearing retainer housing off that both the shift forks were broken. I am assuming from what I see through the PTO hole in the rear and what I can see through the front that there is no more damage to the internals, but of course I could be wrong. So, I hope I have given enough information here, but my question is this. I have an older style Dana 18 with a smaller intermediate shaft and the usual twin stick set up, and I have a couple of Dana 20s with the single shift set up. The problem is I can't just swap the Dana 18s because the shift rails aren't drilled for the single shift plates to be reinstalled and I can't just swap Dana 20 because for one the 20 is a big hole set up and I want to keep the Dana 18 for PTO use. Finally, can I use the front bearing retainer and/or just the shift rails out of the Dana 20 to go back into the original Dana 18 for the proper connection to the shifting assembly or should I put in the weaker, older Dana 18 after I have tried to drill and grind the correct shape on the ends of the shift rails to be compatible with the single shift lever assembly? Thanks in advance for any thoughts, Chris.

 

First, pull out the 18 and disassemble and survey all possible damage. After that is done, then make a decision. The smaller intermediate pin transfer cases usually were 26 tooth and you should have a 29 tooth now. With the weight of the FC I'd stay with the 29 tooth if at all possible. The front housing of the 20 will not interchange with the 18 due to bearing and design differences. It will fit on the case, but the internals are different. If you look on the inner end of the shift rails there may be a number stamped there. If you contact one of the suppliers like Walck's, R&P, etc., they may be able to match up the shift rails. If no #'s then get the dimensions, which direction the slot goes, etc. and give the folks a call. The forks are universal to all 18's so that should no be an issue. I know R&P has stacks of that stuff and I'm sure others do too. R&P can be reached at 503-557-8911. Be patient when you call as it's a small operation and right now you may get either Paul or Tom. Tom isn't real knowledgeable about this kind of stuff but will help any way he can and will get Paul's help. Paul is out hit and miss right now due to a close friend that's dying of cancer in the hospital and wasn't expected to live past two weeks ago. I may be able to help also as I have to go up there later this week when some parts I ordered come in. Nickmil

 

If it will help I have a set of single shift rods in the garage from my cj5 that I would let go cheap. I kept all the parts when I converted to twin stick.

 

Thanks for the info guys. So, what you are saying is the front of the 20 won't swap right in and for weight issues I need to stick with the T-case that came in the vehicle... Which leaves me needing to find the proper shift rails to replace the broken ones. Will just the shift rails from the 20 work? If they won't then I will try to get dimensions, #s, and details like you guys suggested and I will see if they match yours Mcruff. If not, then I will try Walck's. As far as checking for damage internally I will do that, but I was wondering-How did they ever tear the Dana 18 up to begin with? It is super sturdy from what I know about the specimen. After it is all said and done maybe I can get her working again. Thanks for the help, Chris.

 

Nope, the 20 front won't swap in. The shift rails come in all different configurations and lengths depending on what linkage was used and what transmission it was intended for. Most likely the rails from a single stick 18 would be the same but I'd try and measure to make sure. The 29 tooth 18 would be more durable in your application than the small intermediate 26 tooth, that's why I'd recommend the 29 tooth transfer case. Sounds like maybe they bound up the transfer case and tried to force it to shift. That could cause damage that you have described. Nickmil

 

Sounds good, thanks for the responses. I will tear into her to see what I can find out. We will see?! Thanks again.