Rear End ID?

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Rear End ID?

May 06, 2006, 11:42:09 PM

Hi. I just bought an 84 T-bird. This is basically my first Ford, so I'm trying to figure out what's what.

I got these numbers off a tag on the rear end, and I'm trying to make sense of them, but nothing I see in the tech archive here or at coolcats seems to make sense. Can one of you help me?

The numbers are:
AS 4B13
8 75 V462A

Anyone? :)

Thanks!
-Bill

Rear End ID?

Reply #1 – May 07, 2006, 12:13:18 AM

Hmmm, I'm guessing that the 75 designates it as a 7.5" but you can tell that by looking at the cover. The other numbers don't seem to make sense. As I recall, the gear ratio is usually indicated just the same way the rear end size is. For example, a 3.08 (probably what the car has, at least if it's a V8, V6 would likely be 2.73) then it would be denoted 308.

Rear End ID?

Reply #2 – May 07, 2006, 01:12:30 AM

yeah, he's got a 3.08 gear, in a 7.5, nearly as I can tell..

Rear End ID?

Reply #3 – May 07, 2006, 01:52:53 AM

Your missing half the tag info (left side) you have a 7.5" rear with 3:08's

Rear End ID?

Reply #4 – May 07, 2006, 01:59:41 AM

I'm surprised you could even read it, being an '84. I tore into the busted 7.5 on my '85 today and the tag was totally illegible.

Rear End ID?

Reply #5 – May 07, 2006, 02:06:02 AM

If you go over the tag with sandpaper you should be able to read the numbers off of it, or else soak it in WD-40 and se the rust off. My 80 was rusted to hell and I was able to decipher it.

Rear End ID?

Reply #6 – May 07, 2006, 10:10:37 AM

Mine was clear as day. But its wrong now!

Rear End ID?

Reply #7 – May 07, 2006, 09:51:26 PM

Thanks everyone!

It actually looks like the tag got busted off and redrilled so they could stick it back on there. Thanks a ton for the info, though!

I'm sure I'll have questions shortly. Thanks guys!

-Bill

Rear End ID?

Reply #8 – May 08, 2006, 10:32:52 AM

so i have a 3:08 which is the pinion to ring gear ratio, but what's the difference between a 7.5 (which i have) and an 8.8? is it the diameter of the ring gear? and with this whimpy 5.0 that i have, would i see increased acceleration or better fuel economy (or worse) if i changed the rear end? ratios confuse me and sometimes i feel like i'm reading sandscript

which is better accelerating a 2:73 or the 3:08, which is better for economy? and what happens if you goto a 8.8 rear? will they both be effected?

Rear End ID?

Reply #9 – May 08, 2006, 10:46:05 AM

7.5 and 8.8 denote the size of the rear end. The 7.5 has a round diff cover and the 8.8 is more square.

As for gears. The 3.08 is going to be the best comprimise between MPG and acceleration. Go too low like the 2.73 the car doesn't want to get out of its own way. Go too high say 4.11 the car flies like a bat out of hell but the MPG gos down.

Rear End ID?

Reply #10 – May 08, 2006, 12:04:32 PM

going from a 3.08 to say, 3.73, you probably will only lose a couple mpg's on the highway. hell just get a 4.56 and have some fun :D