All right so here may be a silly question, but I'm a bit stumped.
I've got a five speed '83 280ZX with the R200 differential. Will someone please direct me in draining and re-filling this differential? I was under there yesterday and for the life of me could not find much in the way of a drain plug etc. I've got the service manual for my car, but this tiny fact is quite glossed over. I'm not incredibly car saavy so please post in lay-man's terms if at all possible.
I had posted earlier about squeaks coming from the rear when I was in gear and no acceleration. The squeaks go away when I am out of gear or accelerating in gear. Thanks to those who directed me to the diff. and possibly the u-bolt.
p.s.- if anyone has an extra gas tank around let me know. I've got a rusty one and am interested in buying another. I am in Iowa City, IA, but don't mind paying shipping.

 

I'll have a gas tank for you pretty soon. Yours is a 2-seater car, right?

On the back of the differential, (differential cover) you should see two inset nuts. Both have square insets in them.
The lower one is to drain. Stick the bare end of a 1/2 inch drive breaker bar (handle used for sockets) into that square hole. That should open it. After it is drained, you put the lower nut back in. The one in the middle is the fill hole. Remove that plug and fill fluid in there somehow. When the fluid is up to that level and starts to run out the fill plug, then you're done filling. Replace the upper nut and you're done! I've heard it is always recomended to use organic gear oil in the diff to cut down on noises.

 

Thanks for the tip. I'll have to get one of those square headed tools. That was the trouble, I was looking right at the plug, but I hadn't ever seen a square tool like that. Anyway... thanks
Yeah let me know about the gas tank. Yes, I've got the two seater.

 

The tool is just a Half Inch Drive Breaker Bar. You use the tip that normally a socket would go onto. With no socket on the breaker bar, you insert it into the drain plug. Then turn hard.

On my Datsun, I used an air powered impact wrench. The plug would not budge! I had to use the breaker bar with a steel pipe on the end to get enough leverage to get it out. Not good... probably the first time the oil was changed was when I bought it at 132,000 miles.

 

Thankfully I've only got about 58k on my '83. The car sat for ten years after the previous owner put it in a ditch. He most likely left some gas in the tank, consequently it's all rusty. Whatever, it's mine now. The interior is cherry, the body dented.