Did you try penetrating oil? As I recall that screw has an O-ring on the inside so overtightening is not necessary.

I use a large washer clamped in my pliers and it works every time.
Like ncstar said it don't need overtightening. Once you pop it it will come out ok. it does have a rubber o-ring and that might have stuck so check it when you get it off.

Large washer with vice grips - that was the charm! Done! Thanks very much. I sure's heck won't tighten it up that much when I put it back in. Thanks again for all the help.
woody

I use an old, dull chisel that I kept around because it fits that slot perfectly...whatever gets you through the night

woodster wrote:
OK, so how do you get the fill plug out, the big one with the big slot? I've tried with warm case, and cold, with the biggest flat end screwdriver I own, and with anything else I could find that fit into the slot. It won't budge. Guess I'll have to borrow an impact driver. Any suggestions?
thanks
woody

Well, back to the gear oil question. I have found the difference between GL-4 and GL-5 is the amount of effective antiscuffing additives. GL4 has 4%, GL5 has 6.5% and this is what can cause trouble with yellow metals. But as has been pointed out, we needn't worry about brass in our transfer cases and GL5 is ok. My question now is about the Hypoid designation. As far as I can tell, a GL4 is for hypoid gears whereas GL3 or less are not. But does it have to actually say Hypoid on the bottle if it is a GL4 75-90 weight gear oil? I found some Penzoil full synthetic, GL4, 75-90 wt at a good price, but it only says it is gear oil. I'm thinking it need not specify that it is for hypoid gears if it is a GL4 rating; that the rating is for hypoids. Do you think I understand it correctly? Sorry to make things difficult - that just seems to be the way I am. Thanks
woody

woodster wrote:
Well, back to the gear oil question. I have found the difference between GL-4 and GL-5 is the amount of effective antiscuffing additives. GL4 has 4%, GL5 has 6.5% and this is what can cause trouble with yellow metals. But as has been pointed out, we needn't worry about brass in our transfer cases and GL5 is ok. My question now is about the Hypoid designation. As far as I can tell, a GL4 is for hypoid gears whereas GL3 or less are not. But does it have to actually say Hypoid on the bottle if it is a GL4 75-90 weight gear oil? I found some Penzoil full synthetic, GL4, 75-90 wt at a good price, but it only says it is gear oil. I'm thinking it need not specify that it is for hypoid gears if it is a GL4 rating; that the rating is for hypoids. Do you think I understand it correctly? Sorry to make things difficult - that just seems to be the way I am. Thanks
woody

You are certainly digging way deeper into this subject than I did

At only a half quart every 16,000, price didn't really come into play with me. I just found a synthetic that, based on the required specs, I was comfortable with and went for it. All has been fine for more than 40,000 miles.

Two bits is what I use. Works every time and I can manage to get in there without loosening the exhaust. When refilling I use a funnel with a long tube that I can stick between the pipes. Be sure not to overtighten the fill plug on the reinstall. The o-ring does the sealing work for you. If you overtighten, you will pinch the o-ring and it won't seal properly afterward (I always change mine out every other change anyway).

http://www.redlineoil.com/product.aspx?pid=46&pcid=7

I used Redline manual transmission oil the last time I changed it.
MT-90 GL-4
Works great!!!

Jimbo1 wrote:
Anyone tried Lucas 80 weight? It was the only one I found where I was today that had the GL-4 rating...I've heard their stuff is good. Any opinions?
Jim

Haven't tried the gear oil, but ran their oil additives in my big diesels for the last 2,100,000 miles, I love that stuff.