Hi Diskskratch:

Don't ever doubt your Dad again He's right this time too My Dad was just the opposite. He's a genius when it comes to Math and Science, but my Mom used to have to change the light bulbs when we were kids Lucky for us, we inherited both sets of genes

 

Greetings!

I too thought that the 4wd Aerostars came with LS rear ends, and was surprised when I purchased my 96 4wd to find it has a conventional rear axle.

Obscurely located in my Owners Guide, in the towing section, I found the key to the Rear Axle Codes which can be found on the Safety Compliance Certification Label on the Driver side door post. (I hope this table comes out OK)

Code Ratio
Conventional
22 4.10
23 3.45
24 3.73
25 3.27
26 3.55
Traction-Lok
B2 4.10
B4 3.73
B9 3.55

My 94 which I ordered from the factory with LS had a "B4" rear end, While my 96 4wd has the "24" Conventional rear end.

 

Dracoscott, YOU ARE THE MAN!

I have been hunting everywhere for that info. Now I can stop crawling under Aero's to look at there difs to see if they have LS or not.

 

A limited slip/trac loc/posi etc etc is night and day to a detroit locker.
A locker physically and mechanically locks both rear axles together whereas a posi/ limited slip etc etc locks the rear axles together with sandwiched clutches. with a new set of clutches or an extra clutch plate packed in can make a limited slip work well. But, when I switched from a limited slip to a detroit locker in my 1982 bronco, the difference was unbelievable. I could honestly go more places in rear drive only than stock 4x4's in 4 wheel drive!
Also detroit lockers don't wear out, A limited slip that gets driven hard or is turning big tires wont last long.
By the way, if you just want pure off-the line traction and good strength and driveability/tire wear is not a concern, SPOOL it! A mini spool or full spool are a solid link from one axle to the other. It will never unlock in corners like a detroit will. You can find them on ebay for as little as $20.00.
p.s. a mini spool will not replace a limited slip, just an open diff. a full spool with replace either.
007BRONCO

 

If you have the bucks, install an Air Locker; it uses air pressure and I think clutches to lock up the differential when you push a button. You can use it only when you need it, and the rest of the time, it's an open diff. Heck, you can install one on each end for those conditions where you need true 4wd.

I once drove a Mercedes Galundenwagen that had manually controlled locks on all 3 diffs. They used 3 little levers behind the standard gearshift/4L/2L/2H levers. It can get real busy with all those shifters some times, but I never got stuck in anything.

 

Just a side note a 4:10 Rear end will not increase your top speed. It will decrease it. A 4:10 gear is a lower gear ratio than say a 3:73. The higher the number the lower the rear gear, you will also lose gas mileage on the highway as you will now need more engine RPM to go the same speed. If you have a 3:73 rear, the most common one and you want more top end then you would need to go to a higher rear end like a 3:08. But of course you will accelerate like a snail.

 

I agree and disagree with the last post. 4:10 gears may give you a higher top speed due to your engine being in the powerband rather than below it when drag starts to become a factor. Remember this van is not real aerodynamic despite its name, you may need that extra rpm for extra power at speed. My aerostar tops out at 172 KMH but it feels like it was being electronically limited- the engine had more to go.
PS. The only reason I brought this up is my mustang GT was faster top speed in 4 th gear than it was in 5 th. More rpm/ more power to overcome drag (in most applications)
007BRONCO