Transfer case fill plug hole (1 Viewer)

[88TXCruiser]

Doing some routine maintenance to the "new to us" cruiser and thought it would be good to replace fluid in Differentials and the Transfer case. Ordered up the socket hex plugs and new gaskets as found in a thread on here. Well, the transfer case has this cute rubber boat plug in the fill port hole, and the threads look pretty well stripped out, although I was able to hand thread a plug into it. Is it normal that the threaded section has the "notch" missing?
What should I do now?
Thanks,
Sammy

 

[88TXCruiser]

ok, should have searched more thoroughly first.

Stripped threads on transfer filler hole

The previous owner left us a nice little surprise that we discovered last night. When we got the 60, the PO said he just changed all the oil in the transfer, transmission, and diffs....so it was lower on our priority list of things to check. Mike had noticed some very minor weeping of oil around...

forum.ih8mud.com

 

[OSS]

Keep an eye on the oil level. Check the level at least every 3000 miles. Since your cruiser is new to you, I'd check it every 500 miles until you get a feel for how fast it does or doesn't migrate oil to/from the transmission. Eventually all cruisers (and 4WD vehicles) will experience oil seal wear - allowing oil to migrate between the transmission and transfer case. One can over fill and the other run dry. Keep an eye on it

 

[Spike Strip]

One of the 10mm allen plugs that are substitutes for the stock plug have longer threads and can sometimes catch the last good threads. That is some very soft and brittle aluminum, now. Barely tighten. Use a flat fiber gasket, and use some RTV.

That notch is normal.

There are other fixes, too.

 

[3_puppies]

I've tapped out to 1/2"NPT, I think it is 1/2"

 

[cruisermatt]

tapping out to 1/2 npt is a good quick fix.
Pretty common issue. I've welded up a few holes, added material, and re tapped to the original M18 size. Not worth taking it apart just for this but if you rebuild the T-case one day then it's nice to get it fixed right.

 

[roalco]

Bear in mind that you can fairly easily radially crack those casings in way of the plug holes! A taper pipe thread plug just stightly over torqued will easily do it, as will a soft gasket on a stock steel straight thread plug (the gasket quickly squishes to allow the steel tapered transition (thread to head flange) area of the plug to push radially against the tapered rim of the cast aluminum casing hole.
I've never seen a crack of more than an inch long or so, but they will weep, and may continue to run. Just a word of warning!

 

[Jdog]

Helicoil might be a great option.

 

[cruisermatt]

A helicoil is not a great option because the hole isn’t not a consistent depth. A Time-sert is better but the best (in my opinion) is to completely fill this area with weld and then tap to the correct size. This is a view from inside the case, with a stock 60 fill plug (and gasket) tightened all the way, and you can also see that the plug could also be a bit longer without issue.