Rear Axle identification tag

[Starliner]

I found the tag, but thebnumbers don't seem to match up with the charts in Gary's library.
Any help would be appreciated.

Thanks
Joe

[Gary Lewis]

Joe - According to the illustration below the info we need is probably in the bend on the left.  But it looks like the gear ratio ends in "8".  So if you can clean the tag with a small brush and get a different angle in a pic maybe we can read it?

What are you trying to figure out?  The gear ratio?  What axle you have?  Or the parts list to get new parts?

There are ways to do most of that w/o the tag.  You can figure out the gear ratio by placing the rear end on jack stands and rotating the driveshaft while counting turns of the wheel.  And we can tell whether it is an 8.8" or 9" with a picture.

[1986F150Six]

If 3.08, an 8.8 inch? Then the question would be whether open or limited slip?

[Edit] I just noticed the date of his truck, so most likely 9 inch rear.

[85pig]

Looks like an 8.8 to me, and as you said, 3.08 is an 8.8 ratio.  

[Starliner]

Well, that figures.
I will crawl under there again tonight.

You guys helped me id the front as 8.8, 3.54, not limited slio.

Gary, I like to have all info I can for my notes. Plus, I am going to change the gear lube.

Nice to have spare parts if a rear turns up cheap.
Although, now I am pretty sure that the clunk I hear in the rear is not the rear end, rather, the R.R. brake.
Easy enough to take a look.

Thanks guys,
Joe

Also, for conversation sake with my pals.

[Gary Lewis]

If the front axle is a 3.54 then the rear should be a 3.55 if it is an 8.8".  Ford always made the front axle the same or a little bit higher/taller gearing than the rear axle.

[Starliner]

Ok, Gary,
This might be a dumb question but is there any chance it is limited slip?
I just want to make sure I'm putting the correct fluids in.

I know that the front is not L.S.
I can get a full read on the diff tag if needed.

Thanks,
Joe

[Gary Lewis]

Joe - If you can't read the tag then I'd put one rear wheel in the air via a jack stand and try to turn it by hand.  If you can then either you don't have limited slip or the clutches are worn out.  In that case I don't think you need the additive.

Having said that, it won't hurt to put the additive in.  Try not to get the stuff on you because it is apparently related to a skunk's oil - the smell is awful and doesn't go away.

[viven44]

Joe,

If this is the one with the VIN tag showing Axle 19, its 3.55 non-limited slip 8.8"

No need for additive if everything is stock (you can compare the surface rust on the axle vs the rest of the chassis/frame and see if all of that looks stock...)

I had 2 trucks with that same axle.....

You can conduct the test that Gary suggested. My 78 Bronco failed that test despite being limited slip so I determined the clutches failed. I did use some additive just in case there was some life left…

[Starliner]

Excellent.
You guys are a wealth of info.
I now need to start a thread on carb gasket!!