Mitsubishi Transfer Case to Tera Low231 NP231 ...
Update: March 17, 2008 OK. The doubler kit from D&D Machine is in along with the shifter and cable for the doubler. All the misc cable ends are collected. I found that Ace Hardware carries what they call a 'throttle cable end' which is essentially the same as California Push-Pull's 'rod end bearing' so I picked up two of those as well as the fittings for the doubler 'sight tube'. So far I'm pretty impressed with Tuthill's Unidrum shifter. Seems to be built very well and it's exactly what I was looking for to shift the doubler. Since I plan on mounting the doubler shifter on the side of the tunnel down and in front of the driver's seat I was looking for a way to run the cable through the tunnel sheet metal and then seal everything. While surfing for NP231 information I stumbled across the clutch push rod boot for the old Jeep CJ. It's angled perfectly and the hole is almost EXACTLY the diamter of the cable. I plan on putting one boot on the inside of the cab and one on the other side of the tunnel and run the cable through both.
The adapter is coming along nicely. Slowly, but nicely. Both end plates are done and and ready to be mounted to the center section. I settled on 6" diameter, .5" wall T6 pipe for the center section. After measuring things some more I found out that the OD of the pipe fit nicely inside the NP231's studs with just a tiny bit of recessing to get a socket to clear.
I droped the CAD drawing off at the shop for the transfer case mount today. It took a while but I finally found a shop here in Denver that can laser cut 3/16" and 1/4" plate. After a lot of surfing and not coming up with much in the way of ideas for the second transfer case support I thought of just sandwiching a 3/16" plate between the two t-cases and sticking a foot on it for a transmission mount. I ran the idea past a couple people and then talked to Duffy at D&D Machine about it. Since I'm running the Tera Low231 with a longer snout than the 2006 NP231J input the consensus is that adding the 3/16 plate between the two t-cases wasn't going to decrease the strength any measurable amount. I also picked up the Jeep TJ transmission mount I plan to use. Some probably useless trivia I ran across regarding the NP231 and NP241. Apparently, the planetary gear set from the NP241 can be swaped into the NP231. Why you ask, would you want to do this? The NP231J planetary set only has 3 planetary gears where the NP241 has 6. So, theoretically, the NP241 is stronger. Never having met or heard of anyone that's blown the planetary gears out of either t-case I can't say. The swap does require the correct hi-lo shift fork and hub, in additon to the planetary gear set.
I still have to get the drawing for the Tera Low231 t-case cable mount bracket, the two redesigned t-case shift levers and the Tera Low231 console shifter mount plate finished and off to the shop. I hope to drop those off by Wednesday. Unlikely I'll get this together before the end of April but I'm keeping my fingers crossed.:-)
See the "Box4Rocks doubler..." link below for new pictures of the doubler, the TJ transmission mount and the CJ clutch push-rod boot. You can see the brass fittings for the sight tube on the back of the doubler. I also added pictures of the two shifters and cables. The picture of the shifter with the red-orange handle is for the doubler and the picture of the cable and shifter without a handle is for the Tera Low231 t-case. When I do the swap I'll snip off the end of the original transfer case lever and weld it to a plate that bolts to the new cable shifter. Also visable on both shifter cables are the rubber accordian boots. I decided to add those as added protection from the really fine crud you find in Moab. These cables are not something you want to have to replace every couple years and the boots were less than $5 each.