I picked up 9 inch rear end today out of a 72 1/2 ton pickup for my 53. I did not think to really look at it until I got it home. The yoke is real loose and it does not turn the right axle all the time. Is this an indication of some serious problems? Should I talk to the guy I bought from to see if he will take it back? I only pay $100 for it, so will it be worth keeping and fixing what ever the problem is or find another pumpkin?

 

Um, I think if it’s not a locking diff of some kind, only one wheel will turn, keep it.

 

How do you know the rear end is a 9 inch?

1968/72 F100's offered a HEAVY DUTY rear end as an option...that while classified as a 9 inch, the ring gear is 9 3/8" in diameter, the axles have 31 splines.

ONLY 5 parts are the same as the 9 inch: Two pinion bearings, one pinion race, pinion seal, axle housing gasket.

 

IMO, for $100, to get the proper width axle housing is a good start. With buying anything used, you may want to take it apart anyway, and inspect the bearings, seals, gear teeth and ratio, etc...

 

Bill,
Can you elaborate a little bit on this "heavy Duty" rear end?

what is the best way of determining if it is in fact a 9 3/8" (without taking it apart) and if it was would it make any difference as long as it had the gearing you were looking for on these old trucks?

Only reason I ask is I too am going to go pull one from a 68-72 f100 pickup here as soon as it stops snowing and raining! the local pick and pull had 3-4 of these trucks last time i was there and only $75 with a core or $100 without.

Thanks

Josh

 

Bill, correct me if I'm wrong, but if it is a 4x4, it is more likely to be a 9 3/8" ring gear than not. Also looking at the center of the rear axle shaft on the outside, if there's a rectangle slot in the center, it is 28 splines and dispels it from being a 9.38".

 

if the 9-3/8" truck used the same carrier as the T-Bird/Lincoln 9-3/8" rear (and i assume they would) then the upper rib on the pumpkin is curved down at the end and there is a notch in the housing mating surface to allow the larger gear to slide in place. even if it is a 9-3/8" pumpkin, a 9" pumpkin will fit in the housing and use the same axles as long as you use a 31 spline side gears.

also the rectanle opening on the axle only applies to the 67 and up Mustangs and Torino's as far as telling if it had 28 or 31 spline. every truck axle i have seen has the same 3 drill marks on it no matter if 28 or 31 spline.

rgds
Mike

 

I have a "Heavy Duty 9 3/8 rear end out of a mid 60s "Big Ford."

It's easy to tell, as Mike described - I'll post a picture - if you look at the upper casting ridge, it curves down (is rounded) up at about the 2 o'clock position on the front housing. No plug on mine - but I have the ID tag and it's definately 9 3/8.



Here is an excellent site on 9" rears!

Kevinstang's Ford Nine Inch Differential Page +

 

With respect to everyone here, I would like to point out that Kevin's site is primarily for Mustangs. His info about the slot in the 28 spline shaft is referenced to only cars, which is what I typed in post #6, and in this case, was probably not real helpful information. Both of my car (not mustangs) rears have the slot, but also have a 5x4.5" BP, so maybe the slot is more of an indication it is a smaller BP, than 28 or 31 splines in the case of seeing a 9" rear sitting alone without any car to ID its origin. This would hold true in Kevin's site, since Mustang's share the same BP. As for truck 9" rears, yes it appears they all have the 2 holes, opposite, and one smaller hole in the center. My '66 Bronco has it, my '68 donor for '48 has it, and 6 more 9" rears I have all have it. I can bet they all aren't 31 splines. So mcdonaldm would be right. But they all have 5x5.5" BP. The 9 3/8" of the trucks would also have this BP. I believe the Lincolns had 5x4.5"? So what it boils down to is, you can't tell by looking at the truck, unless you crawl underneath to look at the curved rib. I forget you all may have access to seeing the underside. Where I live, all the junkyard vehicles are stuffed into MN red clay where they sink over time, and the underside isn't viewable. Kevin's site is great, but it's oriented towards cars, not all 9" rears. My $.02 ok, I need coffee now.

 

all very good info, the more info the better. I have read through kevins 9" pages as well and I always like reading more info regarding the use of the 9" in our old trucks.
I agree with havi that just looking at a nine inch not in a vehicle could/would prove difficult to I'd for me. So the more info the better. Good info all.

I was going get some work done outside today, but looks like winter again. Snowing like crazy....
josh

 

Havi and Josh you guys are both right!!!!

Hmmm....I posted a website with rear end ID numbers but it's "hidden" and needs to be approved!!!!

I hope it comes up. It distinguishes between the car and truck rear ends and spline counts. It would probably be very helpful to take along when rear end shopping if the 9" isn't in the vehicle.

 

Link worked for me, thanks.

 

Julie, thanks for the link. I have not seen that site before-now it's bookmarked!
I just looked briefly and it looks like 63-72 ford f100 mostly have a 3.50 gear ratio and 28 splines. My 51 is going to have a T-5 S-10 trans with a .86? overdrive unless I find another one withthe .72? overdrive. I was thinking about what the prime rear end gearing would be for my application? Initially I was thinking that I would need something around 3.73? I dont plan on doing a lot of freeway driving but I guess ya never know?

Thanks

Josh

 

Yeah, I'm not quite sure why that particular link always draws the "FTE auto red flag" but it must have gotten cleared early this morning. There's a lot of good info there.

Here's a really good site for your T-5 as well - lots of different gearing options there!

TREMEC T5 Transmission -Modern Driveline


Josh that sounds like a great combination. I have a C6 which is 1.0 in third. I'm running 15" tires on the back and the 9 3/8 rear I have (WDT-F) is a 2.80 with 31 splines. It fits perfect in the 51!

I'm doing 65 MPH at 2350 rpm. So, I would think you could find something right around the 3.25 and that would be perfect for you (considering a 26" tire diameter or 81 inch roll out) for a 16" rear tire you might get away with a 3.50.

Here is the link of the calculator I used - and it is right on the money!

Gear Ratio Calculator

Have fun!