My 9" tag sys it's a 3300 lb posi traction...anyone else?

[wheelsblank27]

I decoded my rear 9" on my 68' after complete tear down and many different options and opinions (wish I would have done it first ) but I didn't so I guess this is all part of the deal.
That being said here's my dilemma .Does anyone else have a factory posi traction on their bronco? I am 100% that's what I got (from tag and a lot of research ) so that in itself will save me having to buy a trutrac because I really liked how it drove before on and offroad. my question is
Did someone put that tag on later or was that a factory option in 1968?
I've looked on a somewhat reliable website that says they installed a small bearing 9" on that year w a 3300 lb rating and posi traction. I have pictures and will upload after work.
Also if that's the axle I have should I keep instead of a big bearing and just get the big bearing ends and weld on? Or just keep it like it is?
My plans are to take my 3 year old son on the rubicon trail later this year and doing some car shows as well..

 

[DirtDonk]

A Ford Traction Lock (or whatever the proper name is ( edit: "Trac-Lok" for the 9" ) was an option for the rear for most of the production years. And for at least some of those years you could even get a Dana Tracklock (or whatever the name was!) in the front.

Good to post pics though, since there's no guarantee that after 45 years it's still in there.

If it is, it will still likely need to be rebuilt with new clutch plates and springs, if applicable. Although you say it worked well, so maybe it's already been rebuilt?

Paul

 

[Viperwolf1]

3300 lb is the big bearing, 11" brake axle. It was an option for every year until '76. What is the axle code from the VIN tag?

 

[DirtDonk]

As for what to do with it, if you have it out to be rebuilt, and you need to buy new axles anyway (unless you get a set with big bearings and small bearing axles that is), then I would rebuild the clutch pack, and install new 31 spline side gears and buy full-on big bearing axles for your new ends.

Or buy a new HD housing and sell your old one. They're more money than they used to be, but still a relatively good deal. So that's an option.

I think the Truetrac is a better unit myself. No clutches to wear and no special fluids to use. A different torque-bias too, but a good tight Traction-Lock isn't that bad of a unit either, so it's hard to recommend one over the other without some riders.

Either way, if you're rebuilding anything, and especially since you're talking about changing out the ends, I would definitely consider all options. And if money savings is of primary importance (you do have kids after all!), then the route you're describing is not out of line.
But definitely consider the 31-spline side gear upgrade. Minimal cost up front, and many future benefits.

Paul

 

[DirtDonk]

I kind of wondered about the 3300 lb thing too, but didn't take it further.
If you've verified already that you've got small bearings wheelsblank, then I would also take anything that tag says with a grain of salt, as the 3rd member could have been changed out at some point and any of the guts changed as well.

Best to peek inside and see. But for sure measure your bearings/tubes/bolts to verify it's what you think it is.
Maybe the whole axle assembly was changed out at some point?

Paul

 

[Timmy390]

Also if that's the axle I have should I keep instead of a big bearing and just get the big bearing ends and weld on? Or just keep it like it is? QUOTE]

Put new ends on my 9 last summer due to damge in the bearing area. I couldn't find anyone local that would touch it. You need an allignment bar and pucks to get everything straight and a jig to mount the housing in. Looked at getting the pucks and allignement bar made and fabbing my own jig....ended up doing it redneck style.......it worked. No issues thus far.

Here's a link to the thread where it was discussed and what I ended up doing. Got a few pic of the process in my gallery too.....

http://classicbroncos.com/forums/showthread.php?t=206332&highlight=housing+ends

Tim

 

[DirtDonk]

And I have to chime in with this wheelsblank. Just in case you're not aware, the "Posi-Traction" name is a GM corporate limited-slip differential for their own axles. I think it was available for both the 10 and 12 bolt diffs, but not sure about that.

Yeah, I know. It's become totally generic now, with everyone using "posi" like Kleenex or Band-Aid, where the proper general term is actually "limited-slip" but doesn't sound as cool or roll off the tongue quite as easily. Those GM marketing guys really knew their stuff!
I just thought I'd bring it up again in case you were new to all this an not familiar with the different limited-slip diffs available. Each manufacturer had their own names for their versions. And even the catalogs get them wrong now and then. Transposing "trac" for "track" or "Lok" for "Loc" or "Lock". It's hard for anyone to keep track of, so no wonder we settled on posi.

Sorry for the lecture, but a lot of people still don't know this and I like to keep the English language from morphing too far from it's origins, without knowledge aforethought! %)

There oughta' be a list...

Paul

 

[wheelsblank27]

http://www.fordification.com/tech/rearends_ford06.htm
Here's the link, after checking again it's still says it s a factory posi trac and therefore won't have clutches? Am I correct on that one?
Oh yea I guess it's not the heavier rated (coulda swore it said that last time) so I'm gonna end up swapping out for a big bearing at some point (I guess)
The numbers on tag are WEM-B1, 4L11 8AD 699

 

[wheelsblank27]

Or should I rebuild the posi ? It's a real bear to pull apart and my expert adviser says no need to rebuild, they tend to break around the bolts and just to clean and re install... Idk

 

[DirtDonk]

...after checking again it's still says it s a factory posi trac and therefore won't have clutches? Am I correct on that one?

No. As far as I know, all the factory truck limited-slip diffs used clutches. Even those that had "lock" or "locker" in the name. Those were just marketing tools and meant nothing as far as a true locker.
So yes, you have clutches that wear a little bit every time you go around a corner. We used to consider about 60k miles of street use their lifespan before rebuild time.
Not that they'd "failed" at that point. Just that they were not near as effective as they should be.

Paul

 

[wheelsblank27]

Ok, fair nuff . How do I get that blind roll pin out donk? Drill it?

 

[DirtDonk]

Or should I rebuild the posi ? It's a real bear to pull apart and my expert adviser says no need to rebuild, they tend to break around the bolts and just to clean and re install... Idk

Your adviser may very well know a lot of stuff, but a diff that's physically broken is not the only way for them to wear out.
As I said before, clutch type limited-slips often wear out their clutches and are fully rebuildable without ever having broken a bolt. Much less a whole case.

So that broken case criteria is not how to tell if it needs work. And any case can brake around the bolts. I've only seen a couple of Ford Trac-Lok units break like that over the years.

http://www.fordracingparts.com/parts/part_details.asp?PartKeyField=7538

But I've seen many many Detroit Lockers break that way.

Paul

 

[DirtDonk]

Nothing needs to be drilled that I've ever seen.
We need pics I guess.

The whole unit pulls out of the diff, you remove the ring gear, then unscrew three or four Phillips head screws and the whole unit comes apart in two halves.

Blind pins sounds more like something from another type of axle.
A 9" just comes apart as simply as you can imagine. You read Motoman's article. Even though he showed a spool and a Detroit-type diff from Yukon, when you get it down to the point they did, you simply disassemble the Trac-Lok with hand tools and replace the clutch and disc plates.

Paul

 

[wheelsblank27]

Yea, that's not the one I got, mine only has a blind roll pin no screws , i think thats where my problem lies, I'm gonna take pics on lunch here in 20 and post... Stand by

 

[Timmy390]

Trac loc rebuild

Check out these two threads. Nice pics in the first thread of a T-loc. Just FYI, the unit is wired together because when you remove the above mentione three philips head screws, the internal springs will go flying......I didn't use wire, used a bolts/nuts to hold it together. if you buy the "special" tool some places sell, it's just a bolt/nut

http://classicbroncos.com/forums/showthread.php?t=206603&highlight=trac+loc+rebuild

http://classicbroncos.com/forums/showthread.php?t=207409&highlight=trac+loc+rebuild

Tim

 

[wheelsblank27]

Ok, so here are the pics of my diff.

I'm now 99.99% sure it's a posi and not a tracloc. Someone must have installed at a later time but judging by the smell of gear oil prolly 30 ish years ago.
Oh well I'm gonna clean it up and run it, instead of spending 500 on a trutrac.
What to the experts of cb.com think bout it?

 

[wheelsblank27]

Yup, that's what I figured.
So, I guess the mystery is solved then.Factory it had a trac-loc and someone down the line (maybe in the 70's ) changed the diff to a posi trac.
Or... Did I get special rear end as an option? Idk. But I hope changing to th 3:50 s won't turn my 289 into a turd bucket! Did I already say that , idk but I really liked the 4:11 s , even with my new c4 pushing 33" mudders and on freeway i didn't even notice and don't really speed in my 40 year old bucket.

 

[Timmy390]

33's and 3.50's is not going to make you happy. I ran 32's with 3.50's for 15 years and it was a slug. No power at speed which is to say at 60mph, you floor it and nothing happens. Hit a hill and you jsut lose speed.....I went to 4.11's and it really woke up my rig.

I would cut my loses and sell the 3.50's and buy some 4.11's (or lower). Gears are cheap, it's the labor of changing them that kills you. Get a solid spacer for that 9 and ditch the crush sleeve. makes any future repairs much simpler.

What gears are in the front? If you haven't already done so, pop the front cover and see what you have. With the Dana, there is a carrier brake. You have a D30 right? so the brake is 3.54 and down; 3.73 and up......I think.....someone will correct me if wrong.

It's best to pay a little more now and be happy then pay less and have a slug......You will just end up paying more in the long run when you get feedup and make the change.

Tim

 

[wheelsblank27]

Aghhhhh. Damn you for being right, and telling me whqt i thought was gonna happen,I'm friggin tired of this and just wanna drive my shi@!
And here I was gonna start a thread bout how nobody loves the 289 and that I love mine... Reality is about to set in real quick if I run these350 's
That means I'll need to sell my gears and buy 2 sets of 4:11 s , one for the front because the axle I'm buying has 350 s and mine were shot, NOOOOOoooo

 

[Bronconut]

Just some input since I'm not sure you are getting correct data.

That is a picture of a limited slip unit. The earlier models do not have screws to hold the two halves together. My 68 had a factory limited slip unit and it had no screws, the earlier ones were called equa-lok or something and are slightly different. The only way to tell is to pull it apart and count the number of 'tabs' on the clutches. If there are 4 tabs it is the later trac-lok (which has the screws) if it has 5 tabs then it is the earlier equa-lok (no screws). I'm not sure what the strength difference is but I do know the clutches in the equa-lok are much larger than the trac-lok clutches.

The roll pins I think you are referring to hold the spider gear shaft in. Once you get the 2 halves apart, you have access to the rear of these pins to drive them out. Unless you have gear damage though, there is no reason to remove these pins to replace the clutches.

Also, as mentioned above, the brakes and bearing size determine the 'size' of your axle.

Hopefully that makes sense.