I may be over thinking this but I'll ask it anyway.

The center section of my 8 3/4 rear is covered in caked on filth. I'm hoping that the inspection marks have been preserved under all that stuff. How should I go about cleaning off all the grime without damaging any marks that may still be there? I've never had much luck with "Gunk" degreaser and I don't want to just start wire brushing it.

Also, I know a lot of people use muratic acid to clean rusted parts. Does anyone have any tips or tricks to using it effectivly? What ratio works best? What if you don't want to dip the parts? Can you just brush it on full strength? Thanks

I just steam cleaned my axle and all of the marks showed up just fine

My rear axle housing was one giant mass of crusty rust. I had it sand blasted a long time ago. I might have gotten some marks off of it if I'd known about products like EvapoRust at that time. Now those are gone forever. I thought I'd ask about the center section before I did something to destroy those too.

I used dawn dishsoap (or tide) water, brush, and fine/med steel wool to get all mine back.

I used Castrol Super Clean in my situation as it was really tough to get off. At the time I didn't realize or know about the markings. The shiny part was after I took a 3M wheel to it.

Well, it's not looking good. Not much of anything is showing up. It looks like there is a yellow line by the fill plug.(did they use paint or a grease pencil?)

There's an orange dot about the size of a quarter with a run on the top and remnants of a stencil on the side. I can't make it out though.

I assume the muratic acid will just eat everything away right? Is dipping the entire housing in EvapoRust the only option to remove some rust without destroying the marks? I soaked the original coil in EvapoRust and all the marks reapeared.

Thanks for the suggestions so far.

One trick that helped make markings readable on my axle was spraying it down with WD40

I can try that thanks. It's also possible that this center section didn't have many markings. I just don't want to destroy any of them by cleaning the housing to aggressively.

Here is a bottom view from my unit

side view clean with a stiff bristle brush and simple green.

view from the rear. I believe J signifies a 73 and the x means it was serviced with fuild.

Yours has a yellow grease pencil mark by the fill plug just like mine. Mine also has some white stenciling on the side. I think I'm going to soak as much of it as I can in EvapoRust to see if anything else shows up. Right now I'm not seeing anything on the very bottom. Maybe 2.76 gears didn't get any markings there.

Thanks for the pictures everybody.

I believe your correct, Ive heard the paint codes on the bottom did represent gear ratio but never did find out all the details. Im also unsure of the OY1 marking on the side in white Maybe we'll hear more from other members.

The paint markings on the bottom did correspond with the gear ratio, also and additional orange splotch designated a sure grip. I have a chart that tells what splotches were for what ratio.

On my 8 3/4 the # (A914) on the pumpkin coinsided with the same # on the drivers side axle tube, which was most likely the date the rear end was assembled (in my case).

This is what I had posted in another link.
Rear end paint markings

Thanks for posting that list Alan. I've seen it before but didn't know if it was accurate for the later years. I just uncovered two yellow marks on the bottom so it looks like that chart still applies in 73.

After getting most of the grease off the carrier not much was visable. I had some old almost used up EvapoRust so I thought I see if it would do anything. I'm amazed that the marks were still there under the rust. Here's what I found.

orange mark on top...I can't tell if the flat pad is painted black or if it's just dark rust.


two yellow marks on the bottom (2.76 gear)


This is all I could see after cleaning the grease off the side.


After soaking in EvapoRust.(it looks like 10Y with a 7 above it)

Just throwing this back up there.