[bobzoppa]

Over the years driving [31] and the miles, closing in on 2 million ! [over a million across 3 XJ Cherokees] I've tried most of the options.
I guess it comes down to I don't want to spend the entire day changing diff fluids across 3 vehicles if there's a quicker way.

I like the cover drain plug idea best -- if I could weld thin metal like the covers I would but my welding skills are limited to plate steel -Think JB Weld would hold the nut instead
Drilling and tapping the diff housing has occured to me was always worried about strength and internal clearances - how many others have tried that"
Once the cover is off I agree an RTV sealant is the best bet but we're back to that time thing again -6 Diffs = a long day that way
Rubber reusable gasket would be good -- cork leaks for me as often as the RTV
Will look into the transfer pumps for 5 gal containers -- have tried a bunch of smaller ones overthe years --all worked - just slower than I like

Any boat people here? how is the engine oil changed in an inboard speedboat engine ? They're not doing it from below and certainly not pulling the engines for an oil change
I figure there has to be a decent elec pump the boaters are keeping a secret !

[kachink]

Back in the day, diffs had drain plugs. I always wondered why they stopped putting those on.

When I did my D30 a couple of months ago I used Permatex Ultra Black (no gasket). Put a bead on, put the cover on but don't torque all the way. Let it cure for an hour or so, then torque it down and fill. No leaks so far. If you have 6 diffs to do the first would probably be cured by the time you got the last one together.

I have a hand pump that I bought years ago that fits on top of a gallon bottle of GL-5. It has a couple of feet of hose with a plastic end on it that wedges in and grabs the threads on the fill hole and puts the exit hole an inch or so into the diff. I think this is it: http://automotive.hardwarestore.com/...p--648771.aspx

[78FordF150]

Don't worry about stength when drilling and tapping the housing. It is a round hole with threads in it. When the plug is threaded into the housing it is just as strong as if it wasn't there to begin with.

As far as clearance goes I use 1/8 plug that uses a Allen wrench the length is about 5/16in long. If you tap the hole right only about .100 or so will stick out the bottom of the housing. The rest will be in the wall thickness of the diff.

[Cutlass327]

I'd be more worried of catching the plug in the bottom of the diff on a rock or something more that the structural issues...

[Outnumbered]

Originally Posted by bobzoppa

Over the years driving [31] and the miles, closing in on 2 million ! [over a million across 3 XJ Cherokees] I've tried most of the options.
I guess it comes down to I don't want to spend the entire day changing diff fluids across 3 vehicles if there's a quicker way.

I like the cover drain plug idea best -- if I could weld thin metal like the covers I would but my welding skills are limited to plate steel -Think JB Weld would hold the nut instead
Drilling and tapping the diff housing has occured to me was always worried about strength and internal clearances - how many others have tried that"
Once the cover is off I agree an RTV sealant is the best bet but we're back to that time thing again -6 Diffs = a long day that way
Rubber reusable gasket would be good -- cork leaks for me as often as the RTV
Will look into the transfer pumps for 5 gal containers -- have tried a bunch of smaller ones overthe years --all worked - just slower than I like

Any boat people here? how is the engine oil changed in an inboard speedboat engine ? They're not doing it from below and certainly not pulling the engines for an oil change
I figure there has to be a decent elec pump the boaters are keeping a secret !

Boats typically have a drain line from the oil pan that has a fitting/cap or a threaded dip-stick tube. I use a Jabsco Drill pump and some clear tubing to make quick work of boat oil changes. i'm not sure it would pull gear oil though. Especially if its cold.

[bobzoppa]

Ok getting interested in the Drill pumps --I use synthetics and drive around to warm up fluids before changing --as inexpensive as they are I'll try one and see how it works.

Option 2 is , I'm going to take the covers off 3 diffs anyway [leaking ] will mic the housings and see whats there to work with as far as drilling and tapping and then pin down the welding shop I spoke with for pricing on welding a bung on the covers themselves -- shop is owned by an acquaintance and usually only charges me $45 perhr

[Outnumbered]

Originally Posted by bobzoppa

Ok getting interested in the Drill pumps --I use synthetics and drive around to warm up fluids before changing --as inexpensive as they are I'll try one and see how it works.

Option 2 is , I'm going to take the covers off 3 diffs anyway [leaking ] will mic the housings and see whats there to work with as far as drilling and tapping and then pin down the welding shop I spoke with for pricing on welding a bung on the covers themselves -- shop is owned by an acquaintance and usually only charges me $45 perhr

The trick to make them work is to prime them with oil using a small funnel first. Otherwise they can be hard to get started.