Good Afternoon everyone. Along with rockin' out to some Steely Dan "Riki don't lose that number" to Stevie Nicks "Edge of 17" it got me to thinkin'. Numbers?---yeah numbers! I have a Ford Aerostar Assembly manual that I recently acquired off of E-Bay with just about everything but the sink.

Two ways of knowing what kind of an axle ratio you have under your Aero is:

The tag that most of you have bolted to your rear end cover ----OR-----

off of the Safety Compliance Certification Label----as----follows:

Code 24, 34 (Rear Axle with Conventional Differential) Ratio: 3.73:1
Code B4 (Rear Axle with Limited Slip Differential) Ratio: 3.73:1
Code B2 (Rear Axle with Limited Slip Differential) Ratio: 4.10:1
Code 35 (Rear Axle with Conventional Differential)--DANA Ratio: 4.10:1
Code 15,25 (Rear Axle with Conventional Differential) Ratio: 3.27:1
Code 23 (Rear Axle with Conventional Differential) Ratio: 3.45:1
Code 29 (Rear Axle with Conventional Differential) Ratio: 3.55:1
Code B9 (Rear Axle with Limited Slip Differential) Ratio: 3.55:1

This code number is located on the bottom of the sticker 3rd from the right under "AXLE"

 

Covered in this thread, which has links to:
http://www.drivetrain.com/Fordtrkratio_posidata.html
and
http://www.therangerstation.com/tech_library/Axles.html

Neither of those references, nor yours, include the pre-1990 4.10:1 Trac-lok version of "A2", of which I own two:

 

weird really weird. Lets see. Have you checked to see if there is a stamp code on the housing? You're ID says you live in Washington state. In my Ford Factory truck manual page 00-01-23 it shows a "A2" which means Mercury Region for "Ford of Canada". Maybe its a regional issue? I don't know. I guess it would be obvious to rule out an typo or misprint because you own two that show the same thing. This really has me thinking and I'm not going to let it beat me. I'm sorry I couldn't help, but the answer has to be out there. Anyone else got an ideas.--Boz

 

Perhaps you're right about the Canada thing. A CarFax report shows it living in Oregon for most of the time before I bought it in 1999.

The other one was in a Seattle-area JY. I saw the "A2" code, verified that it is, indeed, a Trac-lok, and bought it, pulled it, got it home and then realized it won't fit 1990-up, because it lacks the speedo sensor and has a companion flange rather than a yoke.

My original "A2" diff had the worn bore problem:


and in late 1999 I bought another "A2" diff from a JY in Riverside, Calif. for $50 and that's the diff in the rig today.

So that's three '88-89 Aeros I've personally seen that have the "A2" axle code. Oh, I just remembered, I saw another one, a 1988 w/5-spd in the JY last week with an "A2" axle code.

I have a theory: the axle style (companion flange, speedo sensor) changed in mid 1989, at the same time (approximately) that the door sticker went from that "old" style shown above (my '89) to the newer black-and-white style. And every Aero I've looked at in the JY (and that numbers about fifty of them) that had the later B&W door jamb sticker had either open (nn) or Trac-lok (Bn) designations. IOW, Ford seems to have dropped the "Ax" designation when then went to the speedo-sensor-equipped diff housing.

Just a guess.

What I'd like to know is: does anybody have a Trac-Lok axle pre-1990 that has a Bn code on the door jamb sticker?

 

our beloved Aero was Ford's dumping grounds for unused production parts from terminated models for years....
Ford was actually doing us a favor...we got parts that were tried and true road tested...the old 7.5 rear ends were the over runs of the F150, Ranger and Explorer yearly upgrade changes, so we got all the strange oddball undocumented stuff, but all is good....

we got the end product of Ford refinement of the famous 3L and 4L OHV designs...we love our engines

Ford could not give me one of these DOHC V6 designs with the miles of flopping chain, 4 expensive camshafts and 24 valves to wear out....super expensive to work on...definite 150,000 mile throw away cars

 

Hey Boz, my axle code shows "22". Your explanation didn't show a "22". What does it mean? My Aero is a '93 3.0L with automatic tranny. I am the original owner and my Aero was produced in St. Louis. I have another '93, but it is a 4.0L. The axle code on it is B9. Are these axles interchangeable?

 

http://www.therangerstation.com/tech_library/Axles.html shows axle code "22" to be an open 7.5" diff, 4.10:1 .