I've got a cj-t18 from a 1976 cj7. I know it does not have the 6.34 first gear, but it is still an improvement over the t-150. My question is there a gear that can be changed in my trans to give me the lower ratio? From a Ford perhaps?
Probably the least expensive thing you can do is find a Ford T-18 from a 2WD truck. You then disassemble
both it an your Jeep T-18. You reassemble all of the Ford parts except the mainshaft, use the Jeep mainshaft,
into your Jeep case. Voila, you have a 6.32:1 Jeep T-18!
You could also use the Ford case and tap it to mount the tranny-tcase adapter. Use the same internals as for the
Jeep case. This might make mounting the tranny to your bellhousing easier as the Jeep T-18 uses a unique bolt
pattern, but the Ford T-18 is the same as the T-150.
I've got a Ford-cased T-18 built this way (actually used Scout T-18 mainshaft and adapter) waiting to go in my CJ.