Where is fill plug for rear diff? '87 S-10 4WD

[tylernt]

I've committed the classic newbie mistake of draining a fluid before making sure the fill plug can be removed. Actually, I'm not even sure if I found the fill plug. There's some kind of square drive which may be the plug on the passenger side, a little towards the front of the vehicle, a little over halfway up. My 3/8 extension doesn't quite fit though, the extension seems a little too big. Can't see any other plugs, and my Haynes is no help.

Can anyone please confirm the location of and tool needed for the rear differential fill plug on a '87 S-10 Blazer 4WD?

Thanks!!

[muddog321]

Thats it and its usually a sloppy 3/8 extension but some were 1/2".
Use gloves and a breaker bar or add a cheater bar and it will turn easily then as most or rusted.

[blazee]

It helps to drive the extension in a little with a hammer first and use an extension with the squarest head that you can find. Most have rounded edges and tend to slip and damage the the plug. Go in the direction of tighening it first (just till it moves) to help break it loose.

Do yourself a favor and buy a replacement plug with a hex head to make future service easier. It's much easier to use a wrench than an extension that doesn't fit well.

[tylernt]

Awesome, thanks guys. I'll go through my collection of extensions and hopefully I'll find one that's a better fit.

[tylernt]

Sigh. Upon closer inspection, it appears the square was slightly damaged at some point in the past. My further attempts to remove it have now destroyed it completely, so I will be filling the diff through the vent hose. Looks like the capacity is 1.75qt so I'll just dump 2 in and call it good.