UPDATE: 700R4 installed and running down the road
UPDATE report: Got my 700R4 in with a few hitches but overall not that big of a deal. I had my mechanic install a 700R4 with heavy duty clutches and spline (rebuilt by Action Automotive out of Missouri but I'd be careful if you decide to order from them very long story so PM me) along with a 241c transfer case. Problems encountered.
Flexplate aka Flywheel. Had to find the correct flexplate as the one in my HMMWV wouldn't line up.
The TV bracket. For the amount of talk about this I was thinking this was going to be some kind of major problem but it wasn't. Strangely enough I already had a bracket already in place on the back side of the engine underneath the cover bolted onto the engine that evidently used for the TH400 in some capacity. My mechanic opened the hole up on the bracket to receive the square lock housing (the thing you adjust to have proper placement of the cable that will kick the trans down a gear WOT). My mechanic had fitted it to the metal linkage control arm going to the throttle but after evaluating this closer I discovered that at the end of the kick down cable there was little plastic housing fitting that clamped right on to the throttle body so I ditched the multi bend control arm linkage as it was at an awkward angle. I'm still tweaking it because I need more cable wire length (and less cable plastic housing). Going to cut out some of the plastic cable body to lengthen my cable.
Shifter. I retrofitted my three speed shifter to cover Park, Reverse, Neutral (neutral switch eliminated so it would start in park), Drive and 2cd gear. I don't have 1st gear but meh I didn't have to pay $500 for a 4 speed shifter. This involved fabricating extensions on the bottom of the shifter to provide a greater range of points that the shifter could be moved to achieve all ranges mentioned above.
Dip stick. It was preventing my dog house / inside engine cover from closing. Got a torch and bent it to fit. Looking at maybe taking the 700r4 dipstick and trying to make it work as my bending skills are very lacking.
Front Driveshaft. Had to be shortened about 1.75 inches (I think). Interesting note is that the universal joints on the rear drive shaft were all out of alignment. I was told by my mechanic this will cause all kind of driveline vibrations. I had the driveline shop cut and re weld to align them. This was a bit costly at about $275.
Spacer bracket. Had a bracket fabricated that holds the transmission in place as the one that was on there wouldn't line up to bolt up to the transmission. I was told that holes could have been drilled in the cross member if you didn't want to fabricate the bracket.
After a few miles, I noticed the output shaft of the transfer case that has the yoke for the front drive shaft was leaking. I put a $10 seal in it with several hours of cursing and screaming. Get a yoke puller or similar type tool and a seal remover and don't try to do it on the cheap.
Extended range report. I drove it about 300 miles this past weekend to and from Mobile, AL. Everything worked as it should. At 70 MPH I'm running 2650 RPM. At 80 MPH I'm running 3200 RPM. Yes I know 2800 is sustainable RPM so don't be a debbie downer I just wanted to see what it would do. Gas mileage improved from 11.5 MPG to 12.5 MPG. I think I could get better if I held her at a steady 60 or 65 on the interstate but the whole point of going to this 4 speed is so I can cruise at 70.
Next projects: I want to install a temperature gauge to monitor the temperature of the transmission oil. I also want to install a lockup for highway use. I'm looking at this one that works off the brake light but I'm not sure how I'm going to do that as this system is 12 v and well brake lights are 24 v. I'm open to suggestions on this.