Originally Posted By: Torkenstein
Then how about transmission and differential drain / fill plugs that often have a tapered pipe thread without gasket? These need their own special sealant depending on metals (brass, aluminum, steel) operating temperature and retained fluid type. For steel into steel (differentials) I use blue loctite, as GL5 gear oils can be pretty aggressive at dissolving many RTV's. For steel into aluminum, like my Jeep NV3500 manual, a teflon-based pipe putty works well. Never teflon tape that shreds into strips that can block oilways.
Never dealt with one. Always Honda transmissions with a straight drain plug. The GM transmissions dropped the pan. The oddest was the 2004 Subaru with a T-70 Torx head, but the bolt itself was straight. Most filled through the dipstick hole. The only car I've serviced with a transmission fill bolt was my '95 Integra GS-R. I needed a flexible funnel to reach it. I'd just fill it with the estimated amount. When it got close I'd fill slowly until the oil started overflowing out the hole. Once it was sealed, it wasn't going to leak since it was hermetically sealed. I remember reusing some fiber washers for the fill plug, but my Integra used the common M14 aluminum washers I bought for maybe a quarter each at the drain plug.
