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drill hole in bottom of difs?!?

mikeny59

NAXJA Member #300
Location
NY and/or Fl.
Sick and tired of pulling the dif covers to change fluid, want to drill and tap 1/2"-20 hole and use a magnetic drain plug.

Friend at work said this will significantly weaken casting, may cause a crack to propigate or even a castastrophic failure of housing.

I have seen allen drain plugs on Xterras, any advice?

I know I could drill out the bottom of the covers and have a nut brazed on, but trying to go low budget, don't have access to welding/brazing equipment. Already have drill and tap stuff.

Thanks...
 
Nissans use axles like a Ford 9", correct? Those do have drain plugs a lot of times becuase it's a pain in the ass to pull a center section to drain fluid.

Those axles are also made out of sheetmetal - as in not a cast unit, that could make a big difference.
 
when you get an arb they have you drill a hole in the top
 
You could go an play on the rocks when you felt you needed to change the oil.

I think its perfect if you want to get it ripped out
 
A drilled hole should be just fine - provided you fill it (with a screw or a plug.)

The material may be thin - you could have trouble getting a good seal. Brazing a bung in to accept a plug would be better, since you'd have more bearing surface on which to seal. Brazing can be done with propane/MAPP and oxygen, with a little practise. Brazing to cast should not pose a problem - but you can go ahead and preheat anyhow.

Do not put the plug at the lowest point on the housing! If you look at OEM drain plugs, you'll note they're a bit offset - that's what you're after. You don't want your drain plug to be the lowest point on the axle housing, do you?

A couple things I've found handy on fluid changes...
1) Install a shortly 5/16"-18 stud in the very top hole (or whatever thread size your cover screws are.) Loosen that nut, then remove the screws. Let the fluid drain out, remove the nut, then clean. Put on the new gasket, put on the cover, put the nut on loosely. Line up the holes and put all the screws in loosely, then torque.
2) Replace the OEM steel fill plug with brass - should be 1/2" NPT. That way, it won't seize, and you'll be able to pull it out easily.
3) I don't use sealer on any "maintenance" gaskets - it makes them easier to clean. Paper (or cork) gasket only.

That stud is probably the best advice I can give you - it saves you dropping the cover into your drain pan...

5-90
 
Unless you have an after market cover it should be stamped steel, which would be easy to drill and weld not braze a bung to... drill the hole yourself then take the cover to a shop in the minute it would take to do I bet they probably wouldnt even bother charging you, it would take longer for them to ring you up a bill
 
With as scrapped up as the bottom of my dif gets, I would hate to try and get a plug back out.
 
Appreciate the responses, including the vulnerability of the plug at the bottom - realized - duh - oil pan plug is offset, tranny way up there.

I thought about removing the hex head so the bolt sits flush, and just cleanly hacksawing a large slot for a screwdriver, but then there's no outer gasket surface to prevent weeping, unless there was some sort of shoulder at the top of the hole. Told you I was going the cheapo route.

An npt could solve that problem, I think the design is tapered mainly to prevent leaks w/o a gasket, no?

The Nissans' allen sits flush, must have some sort of bevel up top.

To be honest, I've always used rtv, never gone the gasket/indian head route, I'm probably b*%@#ing and moaning more about the rtv mess/set-up time, the former seems easier, still, going to somehow get this done via the housing, Bretts' link seems interesting. Really want to make this maintenance task easier.

Thanks,
 
Why the heck are you changing fluid all the time? You only need to do it like every 50,000 miles. (even if you did at 25,000, it wouldn't be more than once a year) If you're getting water in there, it's time for some extended breathers.
 
1996cc said:
Why the heck are you changing fluid all the time? You only need to do it like every 50,000 miles. (even if you did at 25,000, it wouldn't be more than once a year) If you're getting water in there, it's time for some extended breathers.


SPOBI

I change mine religiously about every 8 to 10 wheeling trips or 10k miles... still havnt put 10k on my jeep in the last 3 years lol.

Water gets in through seals... change EVERYTIME you do mud or water. Just for good search info.
 
1996cc,

I do alot of routine frequent preventive maintenance, combined w/ Scrappys' response. Done just about all the mods in the last eight years I can, most expensive, this would be cheap and functional.

Btw, last time I did the rear dif, the freakin' rtv made the cover squirm around so much that I crossthreaded one of the bottom bolts on the 8.25, and said screw it until next change, except it developed a leak, first time ever doing difs.

This was maybe the third time I ever crossed a bolt in my 47 years, I even managed to split the case on my 242 on the ground to do a currie/sixstates 242 to 231 tailshaft/flange sye 110k ago successfully, so I'm not ham-fisted. Again, In my mind doing the difs is akin to dropping the oil pan to do change the motor oil, call me anal :confused1

Thanks again for the many replies,
 
Last edited:
As was stated above by another person, use a hand operated suction pump. Pump the old oil out, pump the new oil in. Very easy. You can pick them up for about $10.00. I haven't pulled the diff cover on my XJ in nearly 5yrs, but I change the fluid once a year. Takes about 30 minutes and is practically mess free. That seems like a much better solution than drilling/tapping/brazing holes and such.
 
I added bungs and plugs (1/8"mpt) to both my covers....yes they stick out...no, i don't do rocks...and i drain and refill my lube every time i go to the mudhole.
 
If your vent hose is working properly, why would you get water in it???
You would have water up to the headlights before it would get in the vent tube. I change my diff lube about every 180,000. haven't had any problems yet. I DON'T do mudd.
 
bigo -

The seals aren't a 100% seal (since the shaft has to move across it), water seepage can and will happen.

I understand the want for a drain plug - I LOVED the plug in my old Courier and have considered it for the Jeeps however I do wheel in rocks and didn't want to tear a plug out or bugger up a recessed allen.
 
I appreciate the link to the hd dif covers and the suction pump idea, the only types of wheelin' I do is beaches on LI, NY and beaches and mild trails in Fl., also snow here NY.

I don't believe that a suction pump can draw up any metal in the housing (IMHO), especially important to me since by not removing the cover I'd have to rely on what crap is on the magnetic drain plug and in the drain pan to assess the innards. Maybe for the stupid lawn mower I have that requires one to invert the thing to drop the oil, the suction pump would be appropriate.

Plus again I have all the taps/bits and plugs lying around anyway and don't have the $$$ or need those covers, though they are very tempting.

I sometimes get past the top of the seals when on the beach, should have mentioned that too in regard to relatively frequent dif fluid changes I tend to do...

Maybe if I can get the downtime to install the trutrac/auburn/4.10's I bought maybe three years ago, the cost of the covers could be justified, just not now,

Thanks, I think the ideas and advice was worth this thread,

Mike
 
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