Hello. I am new to the LR2, but have been a mechanic for many years. Please don't judge too harshly. I walked into doing this mod with very little info to go on. I have gone through the trial and error so you don't have to.

This all started because I went to do all of the fluids in a new-to-me LR2 and discovered that because there is a gear literally right inside of the fill plug, suctioning the entire fluid amount, or even a good portion, was going to be impossible.

I have had enough experience with gear cases of all types to know that I was clearly looking at an unused drain plug boss when looking at the transfer case. Rather than drill straight through the bottom like is done with the typical Ford PTU, I took a right angle drill and and drilled and tapped through this very obvious area.

What did I learn from this experience that can help others? First of all, do not go for a hole as big as I did. I barely barely pulled off a 1/4 NPT hole. As I was drilling, I found a hole size around 5/16" or 8MM to be well more than enough to evacuate the case in short order, even at 40°F. Hot oil will fly out of a hole that size like nothing. Secondly, there is NOTHING behind this spot. When I was done with the hole, I found I could easily push almost the entire drill bit into the case. Zero chance of accidentally drilling a gear or whatever. You can use a drain plug with a nice long magnet, temp probe, whatever, and it will never contact anything. Third, as you make your hole, make it so that way the OUTSIDE diameter of your final completed hole will be about 8mm above the bottom of the case. Do this, and your hole will go along the floor of the case, making it so that every last drop will come out of the case when you drain it. Lastly, remember that this is an UNFINISHED drain plug boss. You will need to use a thread sealant on whatever plug you use, because there is no machined face for a gasket or washer to seal to. I used regular old Teflon tape, and have seen zero wetness after install, using synthetic gear oil.

Additional drilling advice? Start with NEW or freshly and correctly sharpened bits. This case drills like butter. I've drilled Delrin and composite that was harder than drilling this case. Start with a case full of gear oil, and not only will the out flowing gear oil take all of the swarf with it, but you will not have to lube the drill bit either. I can't speak for all drill bits, but my $9 Dewalt bits did not cause the gear oil to travel all the way to the drill. Complete dropoff occurred about halfway along drill bit length. For the real win, have someone pump thick cheap gear oil into the case as you are finishing. The thick oil will grab hold of and take anything with it. When it comes to the tap, I would actually recommend you do NOT use grease on the tap. Grease don't flow and carry away metal. Gear oil does. You will find the gear oil causes everything to be trapped in the tap anyway, or just flow out. You will not spend long drilling or tapping. This is not a super thick case, and again, it drills and taps like butter. I did both in less than 2 minutes. It was just that easy. I also jacked and braced all 4 corners of this LR2 with the rear higher than the front, so gravity would direct all to the drain hole.

I chose to install a little pipe and ball valve because I can, and will be changing the oil every oil change. You don't have to do this, or change as frequently as myself. That's just the way I am choosing to do it. Where my arrangement is concerned, yes, I did wire the handle in place when I was done, and yes, I did plug the elbow so that nothing gets into the ball valve to contaminate it. I will probably use a 1/4 hose barb fitting to the end when filling so I can fill the diff from the bottom-up, like is done with a marine gear case. Filling this case from the back with that gear keeping my hose from getting in is such a pain in the ace. The arrangement comes nowhere near the bottom of the metal skidplate, which I did reinstall.

My apologies in advance if my "unrefeened" mod offends anyone.

 

Almost forgot. I also did the ball valve because it's an easy way to subtract the exact amount necessary after a fill. Makes the process stupid simple.

 

Viceroy,

Nice upgrade!!!

I did something similar on my LR2

Due to to difficulty removing the fluid I removed one of the bolts and drilled a hole so that I could drain the gear oil more easily.

Note: the way I did it doesn't allow me to drain all of the old gear oil. (I do raise the opposite side of my LR2 to drain out as much as I can)

Here is what I did.

Freel2.com - View topic - Transfer box drain


Nice work

Paul

 

Think a 1/8 NPT would be big enough? I imagine it would all drain out eventually, especially if I got it hot first.

That would leave some margin for a bigger hole if I goon up the first one...

 

I quite like the mod. Thanks for the idea! But I am going to go with a plug and not your ball vave... it looks a little risky out there all alone ;-)

 

Going to try this with 1/8" NPT, but I'm just going to plug it without a drain arrangement.

Anyone care to venture whether brass or SS would be a better plug material? Corrosion or thermal expansion considerations?

 

Okaaaay... Got 'er dun.

Easy as Viceroy described, but I came very close to needing some welding or a new transfer case....

Jacked up all corners, to keep it level. My kid was helping. I had a drain pan in place and had already measured and drilled a small pilot hole. Due to the cramped space around the drain pan I relied on my kid to watch the drill from a better angle and warn me if it slipped off center. Well, it did, and she didn't. Sigh. In the pic you can see the black magic marker for *should* have been the bottom of the hole.

By the time I realized it, it was too late, hole was already too deep. The drill hit the side of boss which pushed it away at an angle early in the process so the hole was just barely accessible for the tap and drain plug thanks to the slight angle offset. If I had to do it again, I'd drill several successively larger pilot holes instead of just one little one. You do need a 90* drill.

I used 1/8 NPT (PLENTY big enough) and a brass square head plug. I chose that so I could drill the head for lockwire, and it worked out because there was no way a hex head plug would have fit after I drilled the wrong place (too close to the side of the boss).

I tapped carefully, a little at a time especially since I knew my plug could not go in too deep due to clearance. Tested the plug each step of the way until I got the depth I needed. Plenty of meat in the case there. Chase the threads with the tap a few times to get as much metal out as possible. I had two liters of fluid so I did a good flush with one of them after the tap. Jacked the driver side up a bit to help it flow out (put it back to level before filling though).



I used yellow teflon tape on the plug, and added a half-**** lockwire.

I bought a syringe with a small tube:
The small tube made it VERY hard to move the fluid, I used a larger hand pump to fill the case, but the syringe was the only way to extract the 100ML. The small hose can be worked around the gear(s) with some difficulty to extract 100ML... even that took some elbow grease and I'm big.

Anybody know how much to extract on a LR? My bootleg LR manual says 120ML, the volvo dude in the video says 100ML. I did about 110ML counting what was in the tube.

I'll monitor for leaks. I think the plug barely bottomed out the threads in the hole, if it leaks I think I'll grind off some wiggle room on the side of the boss and tap it a little deeper.

Next up: Haldex.

 

Has somebody try Carbyne Heavy Duty Professional Quality Suction Gun, that will be easier to suck it out and install. Only 17 bucks

 

Update: The arrangement above leaked a tiny bit. I replaced the square-shaft NPT plug with an NPT plug with an allen socket which allowed me to better control the torque when I tightened it. The square shaft was too close to the adjacent case, my fault for drilling off center. The new plug (with teflon tape) has been leak free for almost two years and thousands of miles.

No way to lockwire the new plug but I went easy on the torque and simply inspected it (and checked the torque) frequently for the first year to ensure it wasn't working out. I keep a close eye on it, should be good if it's lasted this long.

If you just drill it straight in the first place you could use a shafted plug and lockwire for piece of mind.

 

I've never seen safety wire used on anything in cars. When there is any doubt that something like that will move, you use split washers. But because there is a liquid behind the bolt, teflon is not the correct solution, you use crush washers. But the crush washers are NOT reusable, when the bolt is taken out the crush washer must be replaced.