Camarogeddon

I got properly underneath my '85 Camaro Z28 today, and i am trying to identify what contents it is in the rear axle and transmission. I know for sure that the transmission has been replaced, but i'm wondering how old the thing actually is. it has serial number 5YPO77H (see picture)
As well i'm trying to figure out my rear end. It has a limited slip tag, but also another tag with a serial number that i'm not quite sure what indicates (see picture) As far as i can gather, the rear end has a 3.27 ratio, is this the tag from an aftermarket or dealer mounted unit?
axle tag:

tranny serial number:

TheGr8Doughboy

Here's what the haynes manual says reguarding your transmission.

First number year -1985

Second two letters - Model type - just IDing it as a 700R4

Third three numbers day of year built from 1-365

Last letter is the shift it was built on - H is second shift

Chris

Camarogeddon

Thanks.. that info i was not able to find in my service manual... (chiltons)... Think i need to buy a haynes one day, as those are a lot easier to navigate through when looking for specific information. i have haynes for all my other cars.
Odd that the tranny year number matches the vehicle.. I thought it had been changed, but this opens for the possibility that it has been rebuilt instead. doesn't matter that much really, it appears to do it's job so far, other than massive leaking because previous owner who didn't care to tighten the pan bolts to the correct torque...

-Camarogeddon

AlkyIROC

3.27 gear ratio is easy to identify. Only a BW 9 bolt has that ratio. Count the bolts on the rear cover. There will be 9. The rear cover will also have a rubber plug in it. There should also be a BW cast in the bottom of the diff.

The 9 bolt was not offered in 1985. Sounds like someone may have swapped may that.

If for some reason you have a 10 bolt, on the front of the passenger side tube, towards the inside, you can find the axle codes. They will be stamped in the tube and hard to find/read.

Camarogeddon

Thanks for the information. This is really starting to help. And for it beeing swapped, it probably is. My dash isfrom a 92 (says 25'th anniversary on it), it seems i've got parts form quite a number of cars on this thing. Tho, so far it seems pretty free of rot, and that's the important part to me. Mechanics I can always work on.

Hard to find/read is the word... i have gone over all those areas with sandpaper in an attempt to locate the axle codes with no luck. There are a few layers of paint and such on it you might say. But the rubber plug and such is correct. I havent counted the # of bolts yet, but as far as i can gather there are a pretty good chance that it is a nine bolt. There is a marking on the bttom of the diff as well, I couldn't read it, but it is a definite possibility it says borg-warner. Tho, is that limited slip unit that is in there anything to keep, if i'm planning of ending up in the 3 - 400 hp range?.. and will the axle hold up at all?

-Camarogedon