From two trucks that are nearly twins, both axles are 3.55 open as from tag and gear ratio check.

One truck has a "regular" housing and the other has a pretty heavy gaurd on the top side of the U-joint with a rubber bumper. Why the difference and is one better than the other?

 

Just moving this up to see if I can gain some info.

 

the one with the gaurd and bumper more than likely has been swapped into your truck from a later model car. Most Ford cars from the 70's had the gaurd and bumper on them. it was a cheap (but effective) traction device. the rubber bumper would stop the carrier from rotating and plant the tires quicker.

If the other carrier/pumpkin is original, it is the early weak casing (inside the case are the marking WAR, designating the weak carrier that was standard on the early Ford 9"). the one with the gaurd is more than likely a stronger carrier than the original carrier and that is probably why it was changed or maybe the early one failed/broke. All 9" carriers interchange, the only thing that is different is most are 28 spline axles and some are 31 spline axles.

 

Just the info I needed. Thanks. Would it be easier to change the entire rear axle. Looks simplest if I just roll out one axle and put in the other. I think I will keep the "car" model.

 

actually swapping out the center sections on the 9" is pretty straight forward and easy also. if the other rear end is already set up with brake lines and such, it might be easier just to swap out the center sections . this way you don't have to re-hook up the brake lines, bleed the brakes and hook up the emergency brakes.


it's a little bit measier as all the gear oil gets drained out, but its kind of one of those 6 of one 1/2 dozen of the other type deals.

either way is pretty easy to do. if you need instructions on how to pull the center section, let me know and i will write a quick blurb on it.

rgds
Mike

 

Thanks. No problem, no just to do it. Gotta find the miss in the engine first as seen in the engine post below.

https://www.ford-trucks.com/forums/s...d.php?t=472151

 

The part with the guard is the pinion support, and several different companies built pinion supports, most with standard sized bearings but a few did have longer bearings and bigger, stronger webbing. Unless you have one of these there is little difference between a guarded and an unguarded pinion support.

If there is an "N" cast into the case you have something special that was built for rugged duty service. They were used in cars equipped with the 428 and 429 CJ engines. If both rear ends are 28 spline I expect there is little difference between the two, certainly not enough to justify making the change. That is, unless you are making a 500 horse drag machine.

I am no expert, but did find one on the Internet that will give you more information on the 9 inch than you want to know. http://www.kevinstang.com/Ninecase.htm

He also contributed the same article to Ford Muscle magazine -
http://www.fordmuscle.com/archives/2...h/index2.shtml

Frankly, in normal service any 9 inch will work well. I have a 28 spline with a locker on my truck and use it off-road; it has never given me any problems.

 

Where would the "N" be located on the case?

 

Pictures are shown in the link I posted to kevin's site.

 

Thanks. Couldn't get the link to work earlier. Figured it would be there.

 

From:www.kevinstang.com%2FNinecase.htm