NP203 Twin Stick

[OrrieG]

I when I converted to 4WD in 1985 there was no internet with the seemingly unlimited knowledge base. For 13 years I used the NP203 with a Doug Nash Engineering (DNE2) shaft conversion kit. It worked well, the biggest problem was the crappy shifter. Maybe they were ok when new but having them lock up when trying to get out of 4WD got old. I tried all the tricks for disengaging “Lock” but there was enough slop that about half the time the shifter would slip without disengaging the front driveline. This met I had to crawl out with my trusty big screw driver and pry the offending linkage back into place.

I bought a couple of replacement shifters but found they are just as bad, if you have had one apart you can see why. I decided to try and make up a twin stick setup from one of the bad ones. My goals were:
1) Use the stock 203 shifter case and shift plate,
2) Keep the original alignment with the shift arms so I did not have to modify those,
3) Use the hand tools, welder and grinder I have in my shop, no fancy milling, CNC, etc.

This is going to be very detailed and some of it pretty obvious but I want to be complete.

[OrrieG]

1. Disassemble the stock unit. To get the unit apart bend the case locking tab so it lines up with the slotted hole. Remove the two ¼” bolts and nuts. Remove the large 11/16” nut. Lay the case on its side so the flat side piece can be removed. Remove and clean the plates, keeping track of the order and orientation of the linkage plate, shims and thin washers.

2. Take the stock shifter arm and make a template tracing the passenger (inside of the “elbow“). The new shifter will fit on the outside (passenger side) or the stock one. In the picture below drivers side is up, passenger down. I used 3/16” thick x 1.5” wide flat bar because it’s what I had. I checked for clearance before hand, ideally you would use 1.25” wide to match the stock one. I used a cut off wheel to cut about 80% through the metal, then ground back to form a V notch. I then bent and welded to the shape shown in the second photo. Notice that the left side where the shift lever attaches to is bent AWAY from the stock arm. This is to provide room between the shifters to prevent scrapped knuckles!

[OrrieG]

3. Drill two 7/16” holes for the shift lever (or to match yours if different). Then lay the stock shifter on top of the one you made and mark the pivot sleeve location on the new, centered in the flat bar. Drill a 5/8” hole for the pivot sleeve. Check fit you want it to be tight.

4. Cut off the flat bar about ½ “ below the pivot hole. Set the plate with the square opening under the pivot hole with the right end offset UP and transfer a cut line from the new shift arm to the plate. Cut off the plate at the transfer line. Center the plate on the shift arm with the offset UP and bottom flush with the new arm. This is critical because the bottom will be sliding against the other arm. Butt weld the two together taking care to get good penetration from both sides and not warping the plate. Grind both sides flush.

[OrrieG]

5. Next assemble the stock bottom cam. Toss the thin plate. Push the cam up so the neutral index hole is exposed. Weld cam to side of housing making sure the index hole is NOT covered. Take care not to warp the housing using short welds spaced around the perimeter. Grind the two pins and any welds flush with the cam surface.

6. Grind the bump next to the pivot bolt hole. The welded cam acts a filler to keep the shift arm aligned and limit side flexing.

[OrrieG]

7. Remove pin and spring from the stock shift arm assembly. Grind off the rivet on above the oval hole (not shown in these pictures, I had to go back and do it when the arm started hanging up).

8. Place fabricated shift arm on one of the thin washers. For final assembly lube all sliding surfaces with a small amount of white lithium grease. Don’t overdo it, too much grease will attract dirt and crud.

9. Place longer shift plate onto pivot bolt and use proper sized drill bit to align case and two shift arms. Place stock shift lever arm over the long plate and align axis with the neutral index hole. Spot weld the shift arm to the plate, remove and finish welding on both sides with short welds taking care not to warp the plate. Grind bottom sliding surface flush.

[84 400]

Good work man

Here is another write up on it

http://www.wheelindixie.com/forums/showthread.php?t=970

[OrrieG]

10. Reassembly case EXCEPT for the bent tab. Use a clamp to pull the tab side of the case tight and check for binding. If the levers do not move freely grind a little bit off of the stock lever where it hits the case. I had to remove about 1/32". I also found that if I tightened the pivot nut all the way the lock arm would not move, backing it off about1/16 turn and it was fine so I just double nutted it. Do it in small increments you want just enough clearance for the levers to slide and not have any side to side slop. Once you are get it where you want bend the tap back. Install on transmission and align with both transfer case arms at 6 o’clock position and neutral index pin installed. Note that if you got your welds off and there is case interference just adjust the arms until it works, the arms do not need to be indexed since they work independently.

11. Install shift arms. I have two different heights by design, tall one is farthest away from driver seat so I do not have to reach around it to get to the short one. I also wanted to be able to tell them apart by feel, like the old jeeps I grew up in. Tall one controls H-neutral-L arm, short controls front axle lock arm. I adjusted them so they line up when in H-2WD position. After this photo I moved the tall lever to the other side of the arm.

[OrrieG]

12. I have small hands, if you have bigger paws then you can put the passenger side lever on the passenger side of the arm. Give everything a trial run. Do not forget to pinch back the case locking tab. If it breaks just clamp the case halves together and spot weld it.

13. The bottom trim tab fits just like stock. The upper one will need to have the slot enlarged for the second arm. I am hopeful a twin stick boot made for a 205 will work, if not I will have one made out of leather matching the seats with a foam rubber “gasket” to keep fumes out of the cab.

[OrrieG]

Originally Posted by 84 400

Good work man

Here is another write up on it

http://www.wheelindixie.com/forums/showthread.php?t=970

Thanks, just shows there is more than one way to skin a cat.

[OrrieG]

I pulled the shifter today and made some changes, it kept hanging up. I edited the posts above to reflect the changes I made, now its smooth as butter.

[y5mgisi]

Just found this from a Google search. I think I'm going to give this method a try! Thanks!