Installation

The kit comes with these parts: All new replacement seals. All new replacement gaskets. Rear output shift rod (modified to clear the larger 4:1 intermediate gear). Two sliding drive gears (more on this later). Intermediate gear. Front output gear. Input gear.

Now, about those two sliding drive gears. The original versions of the Low300 kit did not include these gears. They re-used the stock gears. The kit now comes as a complete, five-gear set to meet the demands of larger engines. Increased detent pockets on the shift rail help prevent popping out of gear in two low with twin stick applications. This has been a common problem with stock Dana 300 cases and twin-stick kits so it is nice to see Tera Mfg. address this issue.

The original sliding drive gear is on the left. The new TeraLow gear is on the right. The new gear is cut slightly differently to reduce backlash and should better withstand the added torque of V8 motors.

The red circle is highlighting the wide clearance notch in the TeraLow shifting rod. This is required to accomodate the much wider diameter of the 4:1 intermediate gear. The original rod is outside of the case.

A competent home mechanic could install this kit but we opted to use Jason Conover who has installed several Tera Low kits. Jason began the install by cleaning the new parts in parts washer to remove the waxy, protective coating used during shipping. Meanwhile, I removed disconnected the shifter linkage, driveshafts, breather hose and speedo cable from the transfer case.

With the case removed from the Jeep and on the bench, Jason started cleaning the exterior before commencing with its disassembly. Disassembling the case is a bit like working with a puzzle. The sequence is important, especially if you're planning on putting it back together again. It's recommended to use a Dana 300 service manual or take detailed notes during the disassembly.

Removing some of the components required a specific sequence. If you don't have a manual, be prepared to do some headscratching during dis-assembly.

Here you can see a comparison of the stock (left) and TeraLow (right) intermediate and input/ouput gears.

Once the case was emptied of its internals, Jason used an angle grinder to notch a portion of the access opening on the bottom of the case. This was necessary so that the much wider 4:1 intermediate gear could be installed. With that done, the case was cleaned out and re-assembly began. This process was the reverse of dis-assembly except that he replaced the output shift rod, the intermediate gear, the sliding drive gears and input and front output gears with the 4:1 replacements. The new seals & gaskets were also used. If you're unsure of the condition of your transfer case, you might want to order Tera Mfg.'s Dana 300 overhaul kit as well. This kit comes with the bearings & seals needed to completely overhaul the Dana 300. It also includes an intermediate shaft, a shim set for bearing adjustment and a shift fork friction pad set. Project YJ's case was in excellent condition so we left it as is.

The larger diameter of the TeraLow intermediate gear required notching the access opening.

The re-assembled case (we just have to bolt on the access cover plate).