Differential magnet?

An easy question for the group -
My differential unit doesn’t have a magnet (or an obvious place for one to go) inside. Should it?


It certaily wasn’t standard practice at the time. If you want one, get a cylindrical magnet and drill the drain plug for a nice interference fit.

Copy. Thanks for the reply!

Not from the factory. but one these might work. Sorry I don’t know the correct size for the diff off hand.


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Drain plug is BSPT, not NPT thread, both in 3/4". Both have 14 threads/inch, but NPT is 1.05 nominal diameter and BSPT is 1.04 nominal in the 3/4" size.

Revised post to remove erroneous information.

Thanks. An internet search may find one.

I do wonder if the force of the oil splash would not let iron particles stick to the magnet?

69 OTS

Maybe, but it wouldn’t hurt to have one.

Magnetic drain plug on the diff was supplied in the later XJS diffs. Same size for all of the earlier cars. Why not just get one from Jaguar or a good used Jaguar one?

So much for my question!
Thanks Dick

69 OTS

Hey all - thanks for all the feedback/input!

A few data points to share based on what I’ve found -

The threads on the fill and drain plugs are 3/4" BSPT.

I tracked down Jaguar p/n JLM1263, which looks to be a magnetic plug with the proper thread, but many vendors are out of stock or list it as discontinued. SNG has that p/n as superseded by p/n 607172J, but it doesn’t mention anything about a magnet, and the picture shown doesn’t look like it has one. I may be wrong (I didn’t call them).

I was able to find a Land Rover magnetic drain plug with the proper thread, and it seems to be widely available (Amazon, local LR dealers, etc). P/n TYB500120 (also known as FTC5208). It has a square female receptacle for a 1/2" drive. The threaded section is a bit longer than the OEM plug and comes with sealant already applied (although I’m not sure it’s really needed). Fully seated in the drain position, the magnet has ~1/4"+ clearance from the differential ring gear. I did not check for clearance if installed in the fill plug position.

TYB500120 on the left, OEM drain plug on the right:

Fully seated:

Fully seated with ring gear clearance:

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My 1 1/2 has square bolts to fill and drain the differential - I could get the fill one off- but not the Drain plug- so I used a pump. I used 90 gear synthetic oil. N put in until it overflowed out fill tube- I tried metric n sae n sockets closed n open wrenches but to no avail. Any tips on getting a “square” socket?

I ordered some of these a while back. There’s also quite a bit in the archives with approaches others have taken.

Yup. There are different approaches. A stubby 3/8” drive extension fits nicely into an old 7/16” x 1/2” drive 12 point socket. A little masking tape snugs them up.

Craftsman 8 pt. sockets, sold individually, used to be as close as your friendly neighborhood Sears Roebuck store.