Joe and I found ourselves with some downtime this weekend while we replacing his broken bell housing. We decided to remove the interlock pills from his Dana 20 transfer case.

Removing the interlock pills will give us the ability to shift the rear wheels into neutral and the front wheels into low range and perform what's known as a "front dig". This is really handy when your in a competition and wish to avoid taking unnecessary points for backups. (scoring is similar to golf where a lower score is better)

The process is pretty easy. Neither Joe or myself are very accomplished mechanics so if we can do anyone can do it.

DIY Twin sticks

It's worth mentioning here that adding twin sticks to your vehicle does not require you to remove the interlock pills. However, a standard bolt on twin-stick kit will only give you 2wd low. The interlock pills prevent you from accidentally shifting into two gears at once. As you can imaging, that would be the beginning of a bad day.

If you want front digs on your rig, then the removal of the interlock pills is required. Obviously you need to be careful when shifting in and out of gears. On my old rig we created a single shifter dubbed the "Comp Stick" that made it easy to focus on front digs only while in competition. More on that later.

Tear down

	1. Remove the lower inspection cover.
	2. Remove the rear output yoke.
	3. Remove the bull gear (if present.)
	4. Remove the inspection tag and keeper that holds the intermediate shaft in place.
	5. With brass drift or wood dowel pound out the intermediate gear shaft.
	6. Remove the intermediate gear. The bearings will fall out. Make sure you gather them all up. There are also three washers, make sure you keep them too.
	7. Take note of orientation of brass washers. The side with the groves faces inward toward the intermediate gear. They are keyed so they only fit one way.
	8. Remove the dust caps from the back of the case that cover the rods.
	9. Remove the two pugs from the top of the shift rails.
	10. Use a 3/16 allen wrench to remove the locking bolt from the shift fork
	11. Remove front output yoke nut
	12. Shift both rails into neutral. Use a brass hammer to knock the rails backwards or forwards until they are both in the center position.
	13. Turn the shaft closes to the middle of the case a 1/4 turn counter clockwise. This prevents the poppets from locking the rail into the case.
	14. Knock the shift rail forward with a drift to free the shaft from the case
	15. Catch the spring and poppet ball when the shaft comes free.
	16. Finish removing the front housing from the second shift rail. May require some force or tapping from a rubber mallet.
	17. Clamp the shift fork housing into a vise or onto a bench.
	18. Drill out the two plugs found on the side of the shift rail. TIP: Use a bit that is smaller than the actual diameter of the plugs. As soon as the drill breaks the back side surface they should spin free and pop out.
	19. The interlock pills will now fall out.

At this point you are done with the hard part. You just need to clean and reassemble your transfer case. We included some reassembly instructions in case this was your first time tearing apart a tcase.

Reassembly

	1. Start with the reinstallation of the front shift fork cover. We couldn't get a gasket set, so we used rtv to make a gasket.
	2. Place the spring back into the hole and place the poppet ball on top of the spring. Use a small dowel to press in on the poppet ball just enough to allow the shift rail to start into the hole. NOTE: it's easy to let go too soon here and accidentally shoot the poppet ball across the room. Do not loose the ball. Use tape a rag to cover the holes until the shift rail has gone past the poppet ball.
	3. Reinsert the second shift rail. Remember it need to go back in starting with the 1/4 turn. This 1/4 turn is what allows the shift fork to slide past the poppet ball without getting stuck. Use the dowel method again to push the poppet ball down while you get the shaft started.
	4. Reinstall the forward shift lever with the locking bolt. Use a dab of loc-tight and torque to 14 ft lbs.
	NOTE: Turn the shift rod back into position only after pushing the shift rod all the way back into the low rang position.
	5. Reinstall all the bearings and washers. Use a liberal amount of grease to hold the bearings in place while you insert them. There are three washers that go into the intermediate gear. One of those washers goes in the middle to separate the two rows of bearings. So on final assembly it should be: outer washer, bearings, middle washer, bearings, outer washer.
	6. Apply some grease to the brass washers and stick them back into the case with the grooved side towards the intermediate gear.
	7. Insert the intermediate gear back into position and reinstall the the shaft from the back of the case. Make sure that shaft is installed so that the flat edge is facing the locking tab.
	8. Install the rear output yoke.

That's pretty much all there is to it, becides putting it all back into your rig.