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rear diff leaking

bac XJ

NAXJA Forum User
Baltimore, MD
i have a 8.25 and there seems to be a small leak from the differential plug, is all i have to do is replace the plug or is there something else that could cause this problem?
Replace the plug, I did this on tuesday Plug (PN 5207-0428-AA) cost $4.49. Also the diff could be to full on the fluid, thus it heats up expands and push out and around the plug. Fluid level should be 1/2" below fill hole.
Use some teflon plumbers tape on the thread when you reinstall the plug.

it wraps on counter clockwise. :repair:
Plumbers tape won't help, its a rubber lug, they get worn and drip, if it bugs you , or you're losing lots of oil ...eg.... Jeep Marking it's territory , get another plug, cheap easy and painless.... :laugh3:
Check the hole, see if it's threaded. If it is, it will be either 3/8NPT or 1/2"NPT (I can never remember which) and that means you can buy a brass pipe \plug to put in there (for about a buck and a half.) Why brass? It won't rust, and it will last for-damn-near-ever.

I also quit using Teflon tape a while ago - if the threads don't seal on their own (which is why pipe threads are tapered) I use Teflon pipe dope instead. That way, I don't have to remember which way it winds, and I don't have it unrolling across the floor if I drop it. I also have more control over how much goes on.

Anyhow - the rubber plugs are to be avoided if you have the option. They were used not because they were reliable, but because they are cheap (the bane of mass-production.) You've got it now - make it reliable.

Yes they are cheap and dirty, a threaded plug is better, but all of the 8.25's I've seen aren't threaded, I suppose the "correct" way to fix it would be to weld on a good bung and use a pipe plug (higher up if you're lifted and have the pinion tipped way up) - I 'm not sure there is really enough material in the fill hole to cut enough threads deep enough to seal well.....
If you weld the existing bung from the inside there is enough material to tap a NPT,"been there,done that".
Yeah that would make some sense, my own plan is to weld the original plug shut,(should be pretty easy to add a neat patch over that hole, and add a bung up a little higher.