Need Help - Changing rear end fluid

[Z71GUY]

Ok, I'm ready to change my rear diff fluid (just turned over the 60k mark). I noticed that a 3/8 square head is needed to pull the drain plug and fill plug. No biggie I thought.... I tried my 3/8 extension...no luck. I then tried my 3/8 rachet... no luck. Both were very close, but would not seat within the plug. I've been to every store that sells tools and can't find anything that would work. Its either hex or torx head sockets.

 

At this point I'm assuming that everyone has just used their standard 3/8 extension and mine is just out of wack???

 

I'm going to ask this before I take a hammer to the extension to beat it in...

[rjirvine]

I'd clean the plug with a wire brush and some PB Blaster, and let it soak. You could try and clean out the hole in the plug with a small common screwdriver or something too.

 

Next, I'd try a 3/8" fitting on the bigggest breaker bar/extension you have and try and tighten the plug a bit, not too much! That may help you break it free. You could try and pound the fitting in like you were thinking, just don't overdo it of course.

 

If you do get it off, you can get a new fill plug at autozone etc. They are 6 sided and are usually found around the oil drain plug display racks. If I remember correctly, it's a 1/2" size, but not sure. (just take the old one in with you to be sure). The new fitting takes a GM Brake tool (looks like a big allen wrench, or they have sockets that can do it too).

 

Let is know how you do!

[Z71GUY]

Ok, so there is not a special "square head" socket. I should be able to use my 3/8 extension.

 

I did notice that my plug was a bit rusty... I did try cleaning it last night (wire brush)... now that I know the extension should work, I'll continue to clean it and soak the plug.

 

It will be replaced as well... with a new hex plug.

 

Thanks and I'll keep ya updated!

[desrtrat]

put a little antiseze compound on the thread before you reinstall it. will make it so much easer to remove next time

[RyanbabZ71]

I just used my extension. You may want to try to tap it in with your hammer (hard but not to hard) then loosen it

[Rolandd]

If the plug has a 3/8" square hole then the socket extension should work. Tap it in with a hammer, however remember that you are tapping, not taking large swings at it (you don't want to crack the diff case). I have used grease or oil in the hole to help everything come apart when I am done, however often the tool remains stuck in the plug until the plug is reinstalled, giving you enough leverage to remove the tool. No need to replace the plug as you will likely only have to do this one other time in the life of the truck. As suggested above lightly dress the plug in anti-seize lube. If you have to get a new plug, try to find one with a magnet on it.

[pm26]

About 10 years ago I was lucky to find a 12 piece drain plug key set in some catalog and bought it. I do not remember where I got it, the wording on the box says:

"12 pieces drain plug key and T-bar " and the number of the tool set is 33386.

 

This set has been a lifesaver. My '95 Nissan pickup had internal square 13mm drain and filler plugs, 8 total. Nissan does not sell a special tool for this and they told me to use a 1/2 inch extension. Guess, what, it was too loose, because 1/2 inch is 12.7 mm, and the needed tool was 13 mm. I could not get the plugs loose with the 1/2 inch extension. When I got this key set, it had a square 13 mm key in it, it fit great and I got the plugs loose. Even the local Nissan dealer did not have the proper key and asked me where I got that key set from. (I wish I could remember - but it was too long ago).

 

It contains:

 

8 mm hex key

9 mm hex key

10 mm hex key

12 mm hex key

14 mm hex key

17 mm hex key

3/8 inch hex key

8 mm square key

11 mm square key

13 mm square key (this one fit my Nissan)

3/8 inch square key (I believe this one fits the Chevy pickup)

T handle

 

You can use a socket and ratchet or breaker bar with each key as well, which gives great leverage. This set covers just about all vehicles. There is no brand name of the tool stamped anywhere on the box, but it looks like it was made in Europe. This is not a cheap Chinese made set from harbor freight.

 

So, in summary, there are proper tools for every job. You just have to find them.

 

This is a different set than mine, but it is just as functional:

 

drain plug key set

[Z71GUY]

Thank you PM26! I'll end up using my extension as the tool for this job, however I now know there is a "proper" tool for this.

 

I've gone to Home Depot, Lowes, NAPA and Sears... not one person knew what I was talking about and thought I was nuts - they all insisted it must have been hex and I was wrong.