Never had one apart, but seems the Powertrax has more of a "wave" style tooth so it more smoothly disengages. Where a true locker has square cut teeth and has to really "snap" to jump a tooth. Thus the louder noise.

 

If in your wrecking yard searches you come across a rear end in a '68-'72 F100 that has a 3rd member that looks like this....





....I would highly suggest grabbing the axles from the rear end.

Notice the 3rd member has two widely spaced vertical ribs and the top horizontal rib curves downward on the left side.

This is a Ford 9-3/8" rear end (very close cousin to the Ford 9-inch rear end). The 9-3/8" was only installed in the Bumpside F100's from 1968-1972. It will have 31-spline axles and they will be the same length as your current 28-spline axles.

Not that Dentside 31-spline 4-pinion Traction-Lok 3rd members are just overly abundant in the wrecking yards but, they are easier to find than 28-spline Traction-Lok 3rd members. If you had the 31-spline axles from a 9-3/8" rear end, you would be able to run any Dentside 31-spline Traction-Lok 3rd member in your truck (or, any 31-spline single track 3rd member).

The 31-spline axles from a 9-3/8" rear end would also open up the way for you to be able to use the 31-spline Traction-Lok 9-inch 3rd members from '78/'79 Broncos, '80-'86 model trucks or '80-'86 model Broncos.--there are more of these lying around than Bumpsides with a 28-spline Traction-Lok differential. The 31-spline axles will also be around 30% stronger than the 28-spline axles.

As I had mentioned earlier in this thread, there are two different versions of the 9-3/8" 31-spline axles. If the 9-3/8" rear end has a Traction-Lok differential, the axle bearings will measure 3-9/64" O.D. X 1-5/8" I.D. (3600# axles).

If the 9-3/8" rear end has a single track differential, the axle bearings will measure 3-9/64" O.D. x 1-17/32" I.D (3300# axles) --this is the same axle bearing dimensions that are on your current 28-spline axles.

Either 9-3/8" 31-spline axle version (3300# or 3600#) will work in your Bumpside 9-inch housing. You would just need to know which axle version it is to get the right axle bearings.

I have the 3300# 9-3/8" 31-spline axle version in my '69 F100 9-inch rear end. Even with the smaller bearing journal (compared to the 3600# axle) the 3300# 31-spline axle is still beefier than my old 28-spline axle it replaced.

My stock '69 F100 28-spline 9-inch axle on the left. '71 F100 31-spline 9-3/8" axle on the right.





28-spline axle still installed in the rear end. 31-spline axle sitting to the right. Other than the three divots seen on the face of the center register, notice the 28-spline axle has two circular grooves on the register. The 31-spline axle has a smooth register.




9-3/8" 31-spline axle installed in the '69 F100 9-inch housing.









I've had the 31-spline Traction-Lok N-case 3rd member for a number of years. I picked it up from a wreckjng yard for $75.00 (CHEAP!!). I got the 31-spline axles at the beginning of the year. For both axles with shipping, I gave about $225.00 for the pair. Between the N-case and buying the 31-spline axles, I have about $300.00 total invested in them.

It was cheaper for me to buy the 31-spline axles and install the 31-spline 3rd member, than to buy a new 28-spline Traction-Lok differential and swap it into my existing '69 9-inch 3rd member. --and I have the added durability of 31-splines vs. 28-splines to boot. Major win all around.

 

once again thanks for the education , I will be printing this to bring to the PNP

 

I'm glad if the information I've given will be helpful to you in finding what you're looking for.

My interest with the Ford 9-inch started in the '90s. I decided I wanted to put a 9-inch rear under my '68 Mustang so, I went to the wrecking yard to try and find one that would fit. It didn't take long before I realized I didn't really know what I was looking for or what to look in to find the right 9-inch rear end.

My neighbor (at the time) a few doors down was the local Ford parts counter guy. I went to visit him to tell him what I was wanting to do and asked if he had any information on the rear ends, ratio codes, etc. He told me to come by the Ford place that they had something that might help me.

I went there a day or two later and he handed an old master parts catalog that was about 5 inches thick. I brought it home and started looking through it. At first, I didn't know how to look things up in it but, I figured it out. I copied the entire rear end section out of it and then returned the catalog to the dealership, safe and sound.

After that, I would read all the information I could find on the internet or in magazines, etc. on the subject and, for several years, I crawled around under a LOT of Ford cars and trucks, noting the differences in them. When I went back to the wrecking yard(s), I knew what I was looking for.

I've had a couple of '57 Ford station wagon 9-inch rears, several '58/'59 Fairlane 9-inch rears, a couple of Lincoln Versailles 9-inch factory disc brake rears --a '78 and a '79 model (still have one of those --a '79 model), I have an '80 model Mercury Monarch drum brake 9-inch rear end (converted over to Cobra rear disc brakes) and a 1960 Thunderbird 9-inch rear end.

With the information learned, I was also heavily on the hunt for 9-inch Traction-Lok 3rd members. I have about half a dozen Dentside 9-inch 31-spline TL 3rd members in my personal stash. I had been looking for a long time when I happened upon the 1st N-case I found and a couple of years after that when I found the Daytona N-case that's under my truck now. I found very few 28-spline TL 3rd members, compared to 31-spline.

--this is why I say if you had the 31-spline axles from a '68-'72 F100 with a 9-3/8" rear end, your chances would be much greater of finding a 31-spline TL 3rd member to use, compared to finding a 28-spline TL 3rd member in a wrecking yard.

 

Another important thing to know about is the factory differential types. The most common differential in any older Ford car or truck was the Conventional or Open differential --in street terms, a 'single track.' --could also be listed in a master parts catalog as "NL" (Non-Locking).

The most common differentials in the trucks, prior to 1973, were 28-spline and with two pinion gears. Some open differentials had 4-pinions though.

The first 'limited slip' differential Ford used was the Equa-Lok. It was produced through 1968. It was only offered in 28-splines and only with 2-pinions (no 4-pinion Equa-Lok differentials. --pinions is in reference to the small gears inside the differential that mesh with the axle gears. Not the same thing as the (driving) pinion that meshes with the ring gear).

The Equa-Lok had a large conical Bellville spring that applied pressure to load the clutch pack. Too much preload and the differential doesn't want to release smoothly. Not enough preload and the differential clutches will slip excessively. The Equa-Lok is not a good differential for high traction or high torque loads.

In 1969, Ford departed from the older Equa-Lok differential design and came out with the much improved Traction-Lok differential. It was available in either 28 or 31-spline versions and unlike the Equa-Lok, it was available in a much stronger 4-pinion version (as well as a 2-pinion version). A 4-pinion differential will have twice as much load bearing ability as a 2-pinion differential.

Unfortunately though, the first year Traction-Lok (1969) has one potential fatal design flaw to it --the left half of the differential casting has 4 large holes in it. This presents a vulnerable area of the casting, when exposed to high or repeated torque loads. The flexing of the casting can cause the side of the casting to split between all 4 holes and blow the side of the differential casting out.

In 1970 ('70-'86), Ford addressed this problem by casting a solid cover without the holes. The left side surface of the differential will be machined smooth in this area, on '70-'86 TL differentials.

1969 TL differential. Notice the 4 holes on the left side of the differential casting.





Not a great picture from the internet but, this is a blown out '69 TL differential. Notice the crack ran around through all 4 holes, causing the bearing hub to completely separate from the differential.

What's left of a blown out '69 TL on the right.




Revised '70 (through '86) TL with solid cover and you can see the surface has been machined.




I popped this TL differential open, just for your benefit, so you can see what the insides look like, just 'cause that's the kinda guy I am.


The half on the right is the left side of the differential. The portion on the left is the right half of the differential. This is a 31-spline 4-pinion unit from a Dentside truck. On the right is the 31-spline axle gear, 31-spline clutch hub and the clutch pack. On the left are the 4-pinion gears, the 31-spline axle gear and the center block with the 4 preload springs (normally, there would be a hardened stamped steel plate on top of the ends of the coil springs that applies pressure against the axle gear/clutch pack on the other half of the differential.




In this photo, I have the pick pointing at one of the four pinion gears inside the differential --in street terms, many people would call this a 'spider' gear.



Notice the screwdriver is pointing to one of the tabs on the steels of the clutch pack and that there are 4 of them on this TL. An older Equa-Lok would have 5 tabs.




This is a straight-on view of the right side of the differential. Notice at 9:00 o'clock, 12:00 o'clock and 3:00 o'clock, you can see the ends of 3 spring pins (roll pins). This tells you the differential is a 4-pinion unit (1 long pinion shaft and 2 short pinion shafts). A 2-pinion differential would only have 1 roll pin (1 long pinion shaft).



With the 3rd member fully assembled, but out of the rear end housing, you can still see these roll pins to determine, at a glance, how many pinions the differential has. --if rebuilding the differential, the split on the roll pins should be installed 90° to the longitudinal axis of the pinion gear shafts, to reduce the chances of them vibrating out.

'69 TL diff/3rd member on the left, '70-later TL diff/3rd member on the right. The left side cover of the '69 TL differential will have a rougher sand cast appearance to it. The '70-'86 TL differential will be smooth and have a machined face.

 

thanks again , i am going to be fully ready when i hit PNP .
I was going to crawl under pebbles today and see what her pumpkin looked like . (besides greasy as hell)

 

Ultra, I need your guidance.
I have a leaking pinion seal on my '67 9". I am getting conflicting advice:

1) The manual says replace the seal and goes on and on about inch-pounds and pre-load.

2) You Tube videos tell me to scribe the pinion nut, replace the seal and retighten the nut until the scribe marks line up. That way the ring and pinion are not disturbed.

I like #2. Simple. Can I get away with it?


Semper Fi

 

There's a thread on here somewhere where I had written out a step by step procedure of how I do this but, I can't find it.

I haven't seen the You Tube video you mention but it's probably similar to what I do. If you have a beam type in-lb torque wrench (click type won't work for this), it would be helpful to take a preload reading before you take the nut loose but, it can be done without it.

Make a mark one half of the driving pinion stem and extend the line across the side of the nut, companion flange and onto the driving pinion housing. --just for example, you could make the reference mark at the 3:00 o'clock position. (write your starting point down on a piece of paper).

You'll need a 1-1/16" socket to break the pinion nut loose. You'll need to make a reference mark on the outside of the socket that lines up with the reference mark on the nut. Otherwise, with the socket over the nut, you won't be able to count the number of revolutions the nut turns.

Count your CCW revolutions of the nut as you turn it. Once the nut is backed off far enough with the socket, you should be able to turn it with your hand, once the nut gets close to the tip of the pinion. Where the nut finally comes off the threads probably won't be lined up with your reference mark.

For example, if you initially marked it at 3:00 o'clock but the nut didn't fully come off the stem until the 7:00 o'clock position, write down how many full revolutions the nut made past the reference mark and that it came off at the 7:00 o'clock postion. When you go to put everything back together, the 7:00 o'clock position would be your starting position where you put the nut back on. However many revolutions the nut made coming off is how many you will turn it going back on.

Once you've tightened the nut back down to what you wrote down, grab the companion flange and see if you can wiggle it up/down or side to side. If it doesn't move, you're good. If it does have some give, slightly tighten the nut a little at a time until the flange is steady.

Also, DON'T use an impact wrench to take a pinion nut off (or to run it up), unless you plan to replace ALL the pinion bearings and races. The rapid impacts will violently rattle the roller bearing around in their cages and against their races. This will cause brinelling of the bearings were it puts small pock marks in them that will damage them.

 

I believe that was in my thread https://www.ford-trucks.com/forums/1...t-options.html

 

Yep, that's it. Thanks, I couldn't remember where it was when I tried to find it.

 

This is a great thread, should be a sticky...

 

Yes on the above.
Thank you Gem and Ultra. I have read and will heed.
This is the Internet at its best.

 

9-inch rear end production began in 1957 but ended in the cars in 1980 and then in the trucks by the end of 1986. With this, all Ford production of the 9-inch rear end ceased.

There were three major 9-inch 3rd member case designs over the coarse of production. The first case design was the WAA, WAB and the WAR cases. At first glance, they look very similar to the N-case with their double vertical ribs but, there are distinct visual differences between them and the N-case. One of the first things to notice are the depressions in the casting. There won't be any depressions of the casting, on an N-case, in these areas.

Depressions visible above and below the middle rib on the left side of the case. --there's also a depression on the right side of the WAR casting that isn't visible in the photo.



The other thing to notice are the horizontal ribs have a continuous arch to them (do not flatten out towards the extreme ends like a single vertical rib case or an N-case).

The WAA, WAB and WAR castings are made of gray iron and are considered the weakest of the three major case designs. I believe these 9-inch 3rd member cases were phased out of production around 1960/'61. If you see one in a Bumpside, someone put it there. If you see a similar case in a truck and aren't sure what it is, the one positive way to identify it is to pull it from the housing and look at the casting letters on the inside of the case.

If you see WAA, WAB or WAR cast next to the right differential bearing stand, it's best to walk away from the 3rd member. It's an old gray iron unit.



The next 3rd member case revision came around 1961. This is the familiar single vertical rib version. There were various casting revisions of the case but, the latest casting will read C7AW-E. This will be cast in the same location (on the inside of the case) as what is shown on the WAR case photo above).


Common single vertical rib 9-inch 3rd members you will see. --notice the horizontal ribs flatten out towards the ends. N -cases will be the same. WAA, WAB and WAR case horizontal ribs don't flatten out towards the ends.




In the pre-mid '60s, Ford was heavily involved in NASCAR and factory sponsored drag racing. The torquey 427 Galaxies were having problems of tearing the 3rd member castings out, in the area of the pinion supports.

To eliminate this problem, Ford produced the N-case (sometime around '62/'63). It looked very similar to the old, original gray iron double vertical ribbed 3rd members but, there were no depressions in the casting (as pictured above) and the horizontal ribs didn't have a continuous arch to them. They arched and then flattened out towards the ends, like the single vertical rib cases. The first N-cases had 3.063" differential side bearings and there wasn't an "N" cast on the outside between the ribs on the face of the 3rd member. N-case casting number (located on the inside of the 3rd member) was C2AW-A and C4AW-B.


The next revision to the N-case came in 1970. The "N" was cast onto the outside of the case and the differential bearing size was changed to 2.892". The casting number on these N-cases could either be D0OZ-B or, D0OW-B (I have two N-cases with the D0OW-B casting).

These three N-cases below (not mine) show the difference between a pre-'70 N-case without the "N" designation (pictured at upper left) and '70-later N-cases with the "N" designation (upper right and lower). Notice the N-case at the upper right looks like someone took a piece of welding rod and bent it into the shape of an N and stuck it in the mould just prior to casting, while the N on the lower N-case in the photo looks more 'sculpted.'




Visual difference between an open differential (background) and a Traction-Lok differential (foreground). Notice the bolt heads of the TL are partially shrouded by the differential casting, while the bolt heads of the open (single track) differential are fully exposed. Bolt heads on an open differential requires a 3/4" end wrench or socket. Ring gear bolt heads on TL requires a 5/8" socket --an end wrench will not fit on the ring gear bolt heads of the TL.



You can judge if a 3rd member has a high or low ratio, just by glancing at the ring gear thickness. A thin ring gear will be a higher ratio (lower numerically). A thicker ring gear will be lower (higher numerically).

The 3rd member on the left (below in photo) is out of a '79 Lincoln Versailles 9-inch rear. It has a single track 28-spline differential with 2.50:1 gears (also notice the 'hood' sticking out over the companion flange --truck 3rd members don't have this feature). The 9-inch 3rd member on the right is from a Dentside. It has a 31-spline 4-pinion TL differential with 3.50:1 gears. You can see the differences in their ring gear thicknesses.

The Versailles 3rd member has a round companion flange but, it can be swapped out for a U-joint style flange. Typical companion flanges on the trucks are for a 1310 series U-joint but there are some equipped with a larger 1330 U-joint flange.

 

This might be a stupid question
is there any difference in the F250 9" besides the axles having more lugs ?
so if i found a locker in a F250 , I could pull the pumpkin and install in a F100 housing and axles ?

 

Different animal Mike. F250 would have a Dana rear end. No 9" in a F250.