Econoline 100 9 inch rear slip or posi?, is it limited slip or posi? Options

[Vanner1993]

I have a 9 in rear in my van. The tag looks to say 355 for the gears. Is it limited slip, posi, or one legged? If it is a one legged rear, it's coming out.

[claykuch]

Posi is GMs name for this. The Ford used a Trac Loc limited slip. Lots of guys say they have a posi, locker, ect and they don't know what one really is. So if you are upgrading make sure you do your research first. Chances are your van does not have a limited slip. If the tag is missing, you can jack up both wheels put it in nutual and turn 1 wheel by hand. If the other tire spins in the oposite dirrection, it is an open diferential. If they go in the same direction, it might be a limited slip. Also, a worn out limited slip will seem like a open differential. Or do a burn out and see what happens..............

[Vanner1993]

Burnouts is the reason I want to know. Doing a one legged burnout is just lame in my opinion, but both back tires are worn evenly in the center. Not sure if it's from burnouts or just tire wear. I have a Dana 60 with 373's and another 9 inch I would be able to swap in. What would the tag say if is a limited slip rear?

[claykuch]

Burnouts is the reason I want to know. Doing a one legged burnout is just lame in my opinion, but both back tires are worn evenly in the center. Not sure if it's from burnouts or just tire wear. I have a Dana 60 with 373's and another 9 inch I would be able to swap in. What would the tag say if is a limited slip rear?

I think it will have a L before the ratio like L 3.50.

[Tom Snyder]

I think it will have a L before the ratio like L 3.50.

Exactly.

[Vanner1993]

I crawled under the van today to find that there is no rear tag. My guess is that when the gasket was last replaced, the tag was not put back on. I also checked the 3 other 9 inch rears in my yard, 2 of them under 1986 conversion vans which both had 350 gears, and the third which is under a late 70's ford which had no tag.

[1TuffClub]

As another note; it shouldn't be all to difficult to locate a very cheap limited slip (in this case Traction Loc) ring gear carrier in decent shape, and simply pull the 3rd member out and swap out the carrier. No changing of the pinion depth which is the harder aspect to setup on a ring & pinion.

One leggers have their place. I haven't had one in a while, but they definetly have their use. If your not drag racing, or doing spirited type roadcourse driving, or worried about wet or snowy traction, they can be tolerable (if not fun). I've seen a whole lot of different folks when building up a performance vehicle think they were making a ton of power due to the ease of spinning one wheel, only to be knocked down several notches in the local bench racing ranks by their own rig as soon as they put in a posi. From super fun go no where fast single tire incinerator all the way down the block to barely spinning two like 15' or so. Having gone through the process many years ago myself, it can be a funny thing to observe. Hey, atleast with a one legger, you can hammer it all you want around a corner, and the vehicle is much less apt to swap ends on ya. As well burnies on up to speed are a whole lot safer when one legging it, as appose to having the ass end hanging out side stepping right on that line of control, or oh shit she's comin around.

I bet you could get a freshened Trac Loc carrier for a 9 real cheap. I paid 50 bucks (like a year ago) for one custom shimmed real tight for a rare 4.10 Trac Loc 9 3/8" 3rd I have. So you know a much more common carrier for a 9 is gonna be on the cheap.

[1TuffClub]

I crawled under the van today to find that there is no rear tag. My guess is that when the gasket was last replaced, the tag was not put back on. I also checked the 3 other 9 inch rears in my yard, 2 of them under 1986 conversion vans which both had 350 gears, and the third which is under a late 70's ford which had no tag.

Really, the only way to tell without putting your eyes on the ring gear carrier and ID'ing it, is the jack the rear end up in the air test. An open diff will most commonly, when spinning one wheel, have the other one rotate the opposite way as the spider gears do their thing. On a limited slip, usually, if you turn one wheel, the other goes the same direction and if you can put a foot on it like from laying under the vehicle and turning one with your hand and feeling the opposite side with your foot, it should really feel quite locked. As if the axle was one piece locking the wheels together. If the LS is tired, often the other side will just sit still. I have seen a handful of open diffs, that if you only looked to the other side when spinning a wheel, the other side would spin the same direction, but if you put a foot on it or have friend grab it, then you can get a better feel for what your dealing with.

I'd just locate a cheapy freshened Trac Loc ring gear carrier off of ebay, and prepare to pull that pig and swap out the carriers. Casual afternoon job.

[Vanner1993]

Not that I am buying this, but would this be everything I need?
http://cgi.ebay.com/ebaymotors/9%22-Ford-T...id=220450039033

[Tom Snyder]

I also checked the 3 other 9 inch rears in my yard, 2 of them under 1986 conversion vans which both had 350 gears, and the third which is under a late 70's ford which had no tag.

Are you saying that the 1986 conversion vans did have tags? Those are 9" rears? At least the '89 E150 I have does not have a 9". I don't think the '79 does either. They do not have a removable carrier, & have a stamped sheet metal cover on the back.

The tag on the 9" can sometimes be hard to find at first. They should be on one of the carrier bolts that is on the passenger side &, I think, just a bit lower than the middle. Snugged right up tight on the case & usually covered with grease. You have to take a screwdriver & dig around in there to find it.
+1 on what Claykutch said. You might get lucky, but I have seldom seen 9" LS diffs sell for cheap. And Ford don't make 'em no more.

Your e-bay link, maybe it is, but you need to know what you are doing to change them out.

Keep in mind that ring & pinion gears are a matched set.
From here:
http://www.izook.com/tech/samurai/drivetra...andpinstall.htm
"Double check ring gear and pinion for matching numbers, be careful not to mix gears because R/P are matched sets."

Another one:
http://www.patentstorm.us/patents/7299533/description.html
"Typically, the input pinion and ring gear are processed through a lapping operation wherein the teeth are micro-finished such that the teeth of one component more exactingly match the teeth of the other component. This matched set of gearsis thereafter assembled to a differential."

And according to these guys:
http://www.4wheeloffroad.com/techarticles/...nion/index.html
"Although it is not exactly reinventing the wheel, setting up gears does take skill. We suggest taking your rig to a pro if you are the least bit unsure. An improper gear install can translate to more problems and cost you way more than the few hundred bucks you tried to save by doing it yourself."

"Each ring-and-pinion is made in a set and will be labeled with matching numbers to indicate so."

[1TuffClub]

I'm not so sure it would be. I mean, that is like to do an ultra thorough rebuild of a Trac Loc (ring gear) carrier. I don't know that if I bought a used Trac Loc carrier, if I'd be necessarily replacing all those parts. Generally, if the spider gears and springs look good, a rebuild of the posi/LS is just replacing the clutch fiber n steel plates. And possibly the cross shaft. If you bought the cheapest Trac Loc carrier you could find, then you might go ahead and throw a complete kit like that at it. That's just my initial feeling on it. I'm not on a big habit of replacing certain parts, if they don't need it. Oh, and the beveled washers are another common high wear item.

Here is an example of what I was under the impression you were needing.
9" FORD H.D. 31 Spline Trac Loc POSI

But possibly in a 28 spline setup, as I'm not sure what these mids have standard for the rear axles. Just assuming they are normally the lighter duty 28 spline jobbers. As well, for example, this one has the carrier bearings removed. That's another item, that once removed, I'm pretty sure you only want to replace with new ones at that point as I believe they are pressed on. Somebody else can probably confirm that little detail. As well, I would be confirming the carrier bearing diameter that is likely in place on your existing 3rd member. I think the standard 9 inch 3rd member cases may all accept one common sizing. However, on the more sought after Nodular cases there are a couple of different bearing sizes employed there. I have a Nodular 3.50 Trac Loc tucked away keeping the 9 3/8 pig company, and the Nodular 3rd I have I recall having what is referred to as being a big bearing case. Which is referring to the carrier bearing size. The carrier bearing issue might actually be a non issue, in that the ID of the bearings may all be the same regardless, and that size difference I've read about previously may strictly be connected with the outside diamter, which the case would be accepting.

You'll get it sorted out real quick. It's all pretty simple. I just haven't been thinking about these for a few so it's not all fresh on the top of my mind. I'd shoot a few questions you might have to some of the sellers on ebay. There are a number of very experienced businesses selling on there nowadays, and answers ahead of time are free.

[1TuffClub]

Yes, I would agree with Tom forsure on that one. Never ever mix one ring gear with the pinion from another set. They are as he said, matched. When working on used gears, it is very important to get the pinion depth setup very precisely accurate. However, if in your case, where it sounds like you only need to add a Trac Loc carrier to your existing 3rd member, that is relatively simple. I'm not saying you can handle it, as I don't know you or your abilities. But, the pinion depth is the trickier part. The great thing about Ford 9's and Mopar 8 3/4's and other drop out center section style rear ends, is that you don't have to generally mess around with carrier shims, cuss there aren't any. There are carrier adjusters, which allow you to fairly easily check the clearance and contact pattern on a given ring n pinion setup, and if it is fine to begin with, then it is fairly easy to just switch out a carrier, and reset the carrier/ring gear location, and setting the bearing preload. Just replacing a carrier, is ultra easy for any pro, again, the bigger challenge is generally in setting up the pinion gears depth, and associated relationship and tooth contact pattern with the ring gear. In a carrier change, you ain't dicken with the pinion gear.

[1TuffClub]

Here's another potentially cheap er carrier.
9" FORD H.D. 28 Spline Trac Loc POSI

I must say, I haven't paid attention to this stuff in a little while, and wow has the pricing gone through the roof on this stuff. Amazing. Another source on a carrier, once you know what you want/need, might be much cheaper source. I often have gotten the best deals online from heavy racing oriented forums, where the parts I was after were in ultra low demand. Such as a 28 spline 9" Trac Loc carrier likely would be. I'd still personally be shooting for 50 to 100 bucks, but naturally the market you have in front of you at the time that you've decided you need it, will dictate the price. Those two listings I linked, have buy it now prices that to me indicate the reserve may not be real low. Every one I've noticed so far, is like everybody thinks a basic OE Trac Loc carrier is now worth like 300 bucks. Wow.......... I need to go double check some locks lol...........and I'm glad I didn't throw away a standard 9" case I have that is missing the pinion bearing retainer.

[1TuffClub]

If changing ring gear carriers, to add a Trac Loc, or other type of traction device to your 3rd member, always make sure to confirm the carrier bearing size your case requires, and that the ring gear carrier uses are a match.

[n2ri]

most Quadravans had the limited slip on the Dana 60 rear, and they are using a "power pack" (last I checked the rebuild kit for them was same as entire thing also they require special gear lube to work right) assembly of several disc plates on each side. these take about 7 turns (wind up the clutch pack) of one wheel to lock up and send power to other wheel. my 74 does work as I felt it transfer power back and forth between the rear wheels on loose grave hills (if either wheel slips it pauses till it sends power to the other, so not the same as a Posi or locker). my 73 I can not seem to tell doing the test while on lift as it acts like open. but I had it in park so drive shaft was locked. if your going to buy something buy a locker like
Detroit's "True Track" or another geared locker without clutch pacs. not a solid locker for off road either as you will not be able to corner on the road without wheel spin or drive line damage.

I plan on putting one of this type in both front and rear differentials.

Mitch