For a long time I have had my WildHorses twin stick installed into my 71 bronco, but I always wished I could shift into Front wheel low only so I could do a "Front dig". The interlock pins in the transfer case do not allow the front axle to be engaged with out the rear axle. There are many advantages in having front drive only, weather it be doing front digs, or just limping home in front drive if you had a rear drive line brake, or the lamest reason for me is I have a rear spool and a sharp turn to get into my garage so having a way to disconnect the rear axle will allow me to make that turn sharper.
Many people just remove the interlock pills, but in doing this its possible for the case to be shift in Rear high and front low, and that will bind the transfer case until something brakes. Grinding on the shift rails retains the interlock pills and will not allow the case to be shifted in both high and low at the same time, but will allow independent operation of the axles.
|To start you need to first remove the transfer case, this is probably the hardest thing in the whole deal, as many of us have either a traction bar, exhaust, or crossmember in the way to remove the t-case.|
|Once its removed, be sure to collect all 13 needle bearings that come out of the rear output shaft. Most times they stay in the output shaft and you can reach in and get them, other times they scatter on the floor/inside the t-case.|
|With the needle bearings all ready removed, remove the 5 bolts that hold the rear output shaft and housing to the t-case. I am not opening it up as its already filled with a Wildhorses 32 spline output shaft, and does not need any rebuilding.|
|I then removed the front output cover. Behind that cover are a few shims, save all these are this is how the front output bearings are set with pre load.|
|Remove the inspection cover. You can remove this first, I just did not because the air compressor was still warming up.|
|Next remove the front output shaft yoke and housing.|
|Idler shaft. I grabbed hold of the idler shaft and noticed zero play in it so I was not going to replace the bearings. I used a piece of 1 1/4 dowel that I cut down to 2.5 inches. I then removed the retaining key on the idler shaft.|
|I used the dowel to drive out the idler shaft, doing this the bearings are now held in place by the dowel, and not all over the floor.|
|Here you see the dowel in the t-case.|
|Idler shaft and bearings. You see there are a LOT of bearings inside this and replacing them is a headache. If you need to replace them, you can still use the dowel trick to keep them in place while reinstalling the idler gears. On top of those gears goes a small shim (as seen on right) along with thrust washers on the side of case.|
|Remove the front output shaft itself. You want to tap on the treaded end of the shaft to gently unseat the bearing race on the opposite side. Once unseated remove it. Some cases have a snap ring (as seen in the pic) if so you need to use a pry bar to slide that bearing forward to gain access to the snap ring.|
|Remove the snap ring and you can now slide the shaft out.|
|Here are the 2 styles of front output shafts. On the left is the common T-shift output that uses the snap ring. On the right is the J-shift front output. Instead of a snap ring it uses a slight press fit on the bearing. Other then the shaft the only other difference is the front output gear washer. the one for the J-shift case is large because it does not use a snap ring.|
I decided to swap my snap output to the J-shift output because the J-shift output can be removed with out disassembling the case. While it was out, I also had the shaft and yoke cryogenically frozen to increase the strength. If you wish to swap as well, you just need to get the output shaft and the front output gear washer. The snap ring-less output is also the exact same as the Jeep and Scout 10 spline Dana 20 front output as well. Some Scouts also use a 26 spline front output that will bolt in as well, the only issue is there is not a lot of yokes for this output shaft.
|You can now see the forks, you can remove the slider gears, if they don't come out, try shifting the case using the shift rails. Once you removed the gears you can remove the allen screw holding the shift forks to the shift rails.|
|Remove the 2 plugs on one side of the case and use a magnet to remove the washer, spring and detent ball (if yours does have have a washer don't worry, 75% of the cases I have seen don't have one either).. On the other side of case you will only see one plug, remove it and remove the spring and ball. Then remove the shift rails and seals, again if you can't remove one, try shifting the case into different gears.|
|Front shift rail on the left, rear on the right. In the middle are the interlock pins. I lined them up and ground the notches in the rail.|
|Where I am going to grind.|
|All ground out.|
While I was at it I welded on the rail to help keep rear low from popping out of gear (see the detent in the first pic). Here are some pics from "Nobody " about more shift rail grinding.
|Shift rail ungrounded on the left, on the right, you can see the pocket i created on for Rear low.|
|Stock on the left, ground out for the interlock pins on the right.|
|Reinstall the shift rails and the shift forks and sliding gears.|
|I chose to install new thrust washers for the idler shaft. I put some grease on the thrust washer for it to help stick to the case.|
|Because I used a dowel to hold the bearings, I just dropped the idler gears into the case, and used the idler shaft to drive the dowel out. Once the dowel is out, you can install the idler shafts retaining key and bolt.|
|Reassemble the front output shaft assembly. Nothing should of changed, but it should have about 2-7 inch lbs of rolling resistance, if it is loose try removing shims, if its to tight you need to add shims.|
|Reinstall the rear output shaft assembly.|
|Enjoy your new case where you can shift into Front low range only!|
|Here is a diagram of the Dana 20 case.|
Installing the shifters is very easy. Each vendor will be a little different, but here are a few pics of my WildHorses Twin stick setup
The only parts I bought new when I did this was, 1 front output shaft seal, 2 thrust washers, and 2 shift rail seals, as most of the case was in good shape.
Links - "Nobody"'s site http://www.BroncoII4x4.com
Questions? E-mail me