TeraFlex NP231 2LO kit

Installation date: 1/5/02

I have to start out by saying this is one of my most favorite mods so far, but it wasn’t one I’d planned on doing originally. When I had my front D44 built, I had it loaded with a Detroit locker because OX hadn’t yet released their D44 OX locker. The Detroit worked great, but it really put a damper on steering on the trails, and most of the trails I run get pretty tight. The traction was great, but making two and three-point turns all the time now got annoying pretty quick. TeraFlex’s 2LO kit, which disengages the front driveline while still in low-range, seemed to be the answer. I started asking around about the kit and the feedback was all positive, in fact, the only “bad” thing I heard about it was people forgetting they had their rig in 2LO and getting “stuck” until they shifted back into 4LO.

The kit itself is very basic, just a new range fork and shift sector for the transfercase along with a set of new pads for the range fork and a small dash plaque indicating the new t’case shift pattern. The installation is relatively straight forward, especially if you’ve already been in your t’case to install an SYE kit or already have the t’case apart to install an SYE kit. Tera’s instructions start out with the t’case already split apart, so I’ll start there as well. For a details on how to get to this point, read through pages 2 and 3 of the JB SYE install article.

Steps 1 & 2. With the t’case drained and split, unplug the indicator switch from the front half of the t’case, if your t’case has the switch. Next remove the shift detent screw, sprint, and poppet from the bottom of the t’case. Be careful when removing this because the spring can shoot out and you can loose it… If this happens though, you can purchase a new spring from your dealer for a couple of bucks.

Step 3. Remove the nut and washer that connect the range lever to the front half of the t’case. The arrows in the pic point to the lever (bottom) and the connecting point (top).

Step 4. With the output shafts and chain removed, pull out the mode sleeve, mode fork, and shift rail. They should come out as a single unit as shown.

Step 5. Now remove the range fork and hub.

Step 6. Now you can remove the shift sector, this is the piece that the range lever from step 3connects to. Make sure you do not loose the o-ring and bushing.

Here you can see the old shift sector (top) vs the new 2LO shift sector (bottom).

Step 7. Put the new pads on the new mode fork and make sure they seat properly.

Now just reinstall the parts in reverse order (shift sector, then range fork and hub, then mode fork, sleeve and shift rail), reconnect the range lever on the outside of the t’case, and replace the detent screw, spring, and poppet.

That’s really all there is to it.

The install only took a couple of hours at max, and that was including time to take photos. If you’ve already been into the t’case to install an SYE, this kit shouldn’t take any more than 2 hours to install, if that long.

The new shift pattern for the t’case is 2H – 4HI – N – 4LO – 2LO. If you’ve got an XJ, the lever won’t line up exactly with the markings on the shifter bezel, but that’s a minor issue. Shifting between 4LO and 2LO is just like shifting between 2HI and 4HI in that you can shift on-the-fly without having to stop, all other shifting remains unchanged.

One thing that wasn’t obvious to me at first was that since 2LO is 2wd, the “Part Time” light on the dash will go out when you shift into 2LO. This confused me for a moment until I realized that oh yeah!… The part-time light only came on when the t’case was in 4wd, and 2LO was 2wd. DUH… Anyway, I’ve been extremely happy with the kit, it was easy to install and makes the twisty east Texas trails I run a lot more enjoyable now that I don’t have to make all these multi-point turns anymore to get around. In fact, the only ‘bad’ thing I have to say about the kit is that I use it so much that I often forget I’m in 2LO until I’m halfway up a hill or obstacle and get stuck… then I realize I’m only in 2wd!

I’d highly recommend the kit to anyone with a front automatic locker. I don’t know how much benefit those with open differentials or selectable lockers would see, but it certainly couldn’t hurt them. Last I checked, the kit sold for about $200. Well worth it in my book.

For more information, contact:

Tera Manufacturing, Inc.
Sandy, Utah
Phone: 801.256.9897
Fax: 801.256.9879

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