Part III, FJ Cruiser Modifications Before Installation
Now there are a few things to do before Lefty goes in; modifying the transfer case shift lever, modifying the stock auto transmission tail housing, installing a new transmission output shaft oil seal, modifying the transmission tunnel, a little bit of wiring, and plugging a vent.
NOTE: my installation is a single-stick Lefty; i.e. a single transfer case shifter that duplicates the functions of the stock shifter: 2-high, 4-high, neutral, and 4-low in a "J" shift pattern. You have the option of ordering a twin-stick lefty, where one stick shifts between 2WD and 4WD and the other shifts between high range and low range. Twin sticks gives you the ability to run in low range in 2WD; reputedly useful for maneuvering a heavy trailer and also for rock crawling with a front diff lock - the idea being that you could leave your front diff locked and control power to the locked front diff by shifting between 4WD and 2WD. The disadvantages are increased cost and more modding to do; your choice. I chose to go with a single stick for simplicity, plus I like the stealth aspect.
For a single-stick installation, you can use your stock shifter but it must be extended by 1.5 inches because the combination of the adapter plate thickness and the older Toyota transfer case Lefty is based on puts the shifter ball joint aft of the stock location. A 1.5" piece of 0.5"-diameter mild steel round stock is included in the hardware packet provided by Inchworm. With a grease pencil, Sharpie marker, or scribe, mark a straight line the length of the dog-leg in the shift lever, parallel to the axis. You will need this mark to orient the two halves when welding in the extension piece. With a hacksaw, cut your stock shift lever in half, in the middle of the dog-leg and the middle of the line you drew. Make the cut as square as possible, i.e. perpendicular to the axis of the shaft. Remove the rubber boot, spring and spring retainer on the bottom half of the shifter. Dress the surface of the cut on both pieces and make a good chamfer on both ends with a bench grinder or a file. Make a similar chamfer on both ends of the round-stock extension. Make the chamfers angled and deep enough to get good weld penetration; the welds do not have to be pretty (they will not be visible on the finished installation) but they need to be strong because you may have to bend the shift lever for optimal position after the installation. Be sure to re-install the spring, spring retainer, and ball-joint upper cup over them on the bottom half of the shift lever, align the marks on the upper and lower halves, and weld in the extension piece. If you make you mark straight, your cut square, and align everything straight when you weld it up, the modified shifter should work with minimal adjustment later. I didn't take a picture of the cut stock shift lever, but here is mine after welding in the extension. Note the spring, retainer, and ball-joint upper cup in place (with a little brake cleaner or hair spray the rubber boot will stretch enough to fit over the top of the shifter later):
Next, you must enlarge one of the threaded holes in the transmission tail housing enough to pass a bolt shank through that will thread into Lefty. The hole to modify is the passenger-side lower hole
. Drill it out with a 21/64" drill bit.
Be careful to drill it perpendicular to the mating surface of the tail housing. The tail housing is aluminum and drills easily. Dress the hole and both ends of the hole with files to ensure a flat mating surface and no restrictions on the bolt.
Pull the oil seal in the output shaft area of the tail housing with a seal puller or a large screwdriver. If you use a screwdriver, be careful not to score the inner surface of the seal housing. Install the new seal provided by Inchworm; drive it in squarely with a seal driver or a large socket so that it is flush with the end of the seal housing. (NOTE: picture above w/ drill shows the seal installed INCORRECTLY, do not drive in seal beyond flush into the housing.) I found that a 1-1/2" socket I have worked well for this purpose. After installing it, lube the inner diameter of the new seal with assembly lube or a thin coating of grease. Correctly-installed seal looks like this (with coupling sleeve in place):
A little adjustment of the sheet metal forming the transmission tunnel of the FJ Cruiser is usually necessary. If you put Lefty on the transmission jack and roll it under the truck, it is fairly obvious where the adjustment need to be made, where Lefty's front output case will be when installed. Lefty has been clocked a few degrees more than the stock output shaft, to increase bottom clearance on the trail, but this necessitates a little more clearance in the transmission tunnel. Mark an area fore and aft in the tunnel with a Sharpie marker or a grease pencil where Lefty's front output case will reside. Move Lefty on the jack out of the way. Give the area between the marks some good blows with a two or three lb. sledge or dead-blow hammer. You only need maybe 1/2" or 3/4" of additional clearance. Whack away without fear; nothing you can do will be visible from inside the cab. Here is a picture of mine after the adjustment, but the Sharpie marks were hammered off. The picture looks obscure, but it will be fairly obvious to you when you are laying under the truck.
There is one more optional
modification I will mention here. With my installation (granted, the only one I have done so far), I found that the bottom two (short) bolts only engaged threads in Lefty's adapter plate a very short distance and were easy to strip. In fact, I stripped one on my first "final" (not mock-up) installation. In my opinion, this is a weakness in the design of Lefty, but it's possible mine was a fluke or it was my "operator error" since many other Lefties have been installed without this problem. I repaired it with a Heli-Coil insert and then put a second Heli-Coil in the other bottom hole as a preemptive measure. Heli-Coils are easy to install, work well, and you are left with good high-Carbon steel threads in the aluminum body of the adapter plate, much stronger than the original threaded hole. If nothing else, this is an improvement to the strength of Lefty even if no problems are encountered.
If you elect to do this modification, the threads in these (and all mounting bolt) holes are M8 x 1.25 and that size is available from Heli-Coil, Time-Sert, Fix-A-Thread and other similar brands. I will not duplicate the instructions for thread repair inserts in this post, but they are relatively easy to use and come with good instructions. If you have never used one of these thread-repair systems before, the most crucial part is to drill the hole for the insert as perpendicular to the mating surface as possible.
There are three shift sensors on the stock transfer case (two on the driver's side and one on the passenger's side) and only one on Lefty (on the passenger side). All of the sensors are up high near the top, just behind the shift gate. In this picture, you can see two of the three sensors in the stock case at the bottom of the picture:
It is necessary to connect the single sensor on Lefty into the stock wiring harness that was connected to the driver's-side front sensor the stock case. This is the input to the FJC computer that tells the system that 4WD-Low is engaged. If this is not connected, you will not be able to lock your rear differential or use A-Trac. The easiest way is to simply cut off the connector from the stock case with a few inches of wire left on it, and splice it on to the wires from the sensor supplied with Lefty. If you want to preserve your stock transfer case in perfect condition for some later use, then you would need to buy a new connector from Toyota. I didn't and hence don't have a part number for that connector. Since the sensor on Lefty is on the other side several inches away, you will probably need to extend the length of the wires necessary to reach. Use 18 or 22-gauge wire. Put female spade connectors on the ends of the wires to attach to Lefty's single sensor. It does not matter which wire goes on which terminal of the sensor, it is simply an on-or-off signal and has no polarity.
The next step is optional, but recommended: On the stock transfer case, the passenger-side sensor tells the FJC Automatic Differential Disconnect system when 4WD-HI (or low) is engaged, which then activates a vacuum-actuated shift fork in the front differential to move a sliding sleeve that connects an axle shaft to the differential. This is what allows the FJC to engage 4WD on the fly, without having manually-locking wheel hubs. To preserve this shift-on-the-fly function, you will need to install a simple switch to close this circuit manually, in place of the transfer case sensor. If you choose not to install this switch, 4WD will still work but you must come to a complete stop to shift into 4WD, and the 4WD indicator light in the dash may not come on. With the manual ADD switch installed, you simply flip the switch "on" at the trail head and leave it on until you are back on pavement. Then you can shift in and out of 4WD on the fly any time you want, just like stock.
Again, the easiest way is to simply cut the wires off of the stock sensor near the sensor, splice longer wires on to each of the two harness wires, and run these two wires up through the t-case shifter hole in the transmission tunnel, into the center console of the FJC. I used tin snips to cut a small notch in the base of the t-case shifter boot, to accomodate the wires without pinching them. Here is a picture of my two ADD switch wires coming through the shifter hole under the console. The single shift sensor in Lefty is also shown, in the bottom center of the photo:
I drilled a small hole in the top of my center console, in front of the auto tranny shifter, and mounted a simple SPST switch there:
Again, this circuit has no polarity (is either only on or off) so it doesn't matter which wire goes on which pole of the switch. You will want to place this switch somewhere that it won't be accidentally engaged, as it is best to engage ADD when stopped. I also recommend putting several feet of extra length on these wires, so that you can easily remove the center console at a later date without disconnecting the switch. The extra wire can be easily folded or looped inside the plastic center console.
The remaining shift sensor in the stock transfer case (the driver's side rear) only detects when the transfer case is in neutral (between 4-HI and 4-LOW), and it's only purpose is to activate a dash light that says "N". These wires will abandoned in a Lefty installation, and you will be left with only the transfer case shift lever postion to tell you wether you are in 4-HI, neutral, or 4-LOW.
Plugging the stock vent line:
The stock transfer case is vented through a small hose at the base of the shifter ball housing that ties into a three-way pipe fitting above the rear of the transmission. Lefty is vented through the shifter ball joint, and also through the shifter rods cavity into the space between Lefty and the transmission tail housing. You don't want to leave one open end in the three-way fitting; I just plugged mine with silicone sealer. Don't get so happy with the silicone that you plug either of the other two lines that attach to that three-way fitting.