I have a Ford 9" 4-pinion traction-lok unit that I pulled apart today. This unit was advertised as "ready to run", but while disassembling it was found to have all bolts just above finger tight. Everything inside looks good (even the clutches) except for two things. The sheetmetal spring coverplate is broken, and the outer shell of the case has a few places where the clutch tab retainer slots are machined too close to the ring gear bolt holes and you can see daylight through these spots. Is this normal? I've heard Currie makes a billet cover plate, but haven't seen it available separately and don't know if it'll even "bolt on" without additional machine work. Does anyone know for sure or have a part number?
I haven't seen that cover available by it's self for many years. What you have right now is a time bomb. Those covers are very well known for busting and tearing up everything inside the chunk.
After further investigation (and a bit of luck) I found some on E-Bay from QuickPerformance. Could not find it on their web pages though... E-mailed them and was told it will fit a factory trac-lok with no additional machining!
I'll prolly try and set this one up myself, first timer. Is there a difference on those 4 little springs or are they all the same (tension wise)? What am I looking for as far as shimming the clutch pack? Do you know of a downloadable assembly manual?
The springs are all the same. Some people leave 2 springs out if they want it to be a little softer for street use. I don't know of any manual. I shim the clutches in the 9 inch a little looser than I do in a Eaton Posi. If you shim them tight in the 9 inch they will pop and make a lot of noise.
Come to think of it, there was a shim (I guess) as it didn't have either facing material or ears. That little sheetmetal cover was busted in half, would that have been caused by it being shimmed too tight? I'm used to (well, not really) a true locker with the click, pop, and bang when going around corners...
Alrighty, parts are on order. They did have a clutch shim kit, so I got that too. I found a great tutorial on 7173mustangs.com which I plan on using. Would appreciate it if ya'll would look them over and see if there's any bogus info that will steer me wrong:
Alrighty, carrier bearings: How far are they supposed to press on? Is there a spec or anything? The reason I ask is that there is a rather large fillet on the new billet posi case half that doesn't (seem to) allow the bearing to press flush against the case. I can hold it up to a light source and see maybe 0.030" of daylight where it won't set completely flush. The axle end of the bearing is within 0.010" of being flush. I'm afraid that once together and set up, the "forces within" while under load, will change as the bearings seat further...
I think you're right to be concerned, but BGH will clear this up for you I'm sure. In the meantime all I can offer is on the ones I've seen the bearing ID had an adequate radius to accommodate the fillet on the carrier. If I was up against this and had no one to ask I'd relieve the inner bearing race ID enough to clear unless a different bearing would clear.
I have had pinion shims w/ID too small to sit flush w/o being opened up to clear the fillet... but that's a different deal obviously.
The bearing must sit complete against the flat surface on the case. If it doesn't then you will have probblems later. Use a .001 feeler gauge to see if it is seated all the way.
I found a "tip" on Youtube concerning using an old inner race to press the carrier bearings, and bingo! :thumbup: Worked like a charm, now fully seated.
The bearing must sit complete against the flat surface on the case. If it doesn't then you will have probblems later. Use a .001 feeler gauge to see if it is seated all the way.
Checked the clutch stack-up as per the link above, things are not perfectly level, but within 0.009", and I settled on a 0.020" shim. Now soaking the clutches... Put the non-clutch half of the carrier together and managed to break one of the concave spider gear shims. I'm hoping QP will send me one. So that's on hold.
Started on the pinion and found the following. Had to hammer/pull the yoke on/off every time. Although it gets easier each time, I still need to pull it on with the nut and use a puller to get it off. My solid spacer assembly (0.443" bare and 0.017", 0.020", & 0.041" shims), even without shims, was too thick to give the right preload. I ended up turning 0.015" off the face and using the 0.017" shim to get 22 in/# preload using my old (sanded slip-fit) bearings and races. Will this change when I swap to the new bearings & races?
The end of the pinion is marked 1.028", is this measured from the end of the pinion to the carrier bearing surface? Is this a "must" or just something to start with?
Think I found a use for a few of my old Buick turbo 6 head studs, they'll make a great ring gear alignment/assembly tool.
I don't understand why you used the loose fit bearings instead of putting the new bearings on to start with. There is no need to install and remove the bearings other than shimming the spacer, and you should be using your press to remove and install the pinion for that job, including removing the yoke. Yes, the preload will change when you change the bearings.
The marked pinion depth is almost always just a good place to start. It's always been off by around .003 when I tried to use it.
Thanks. I guess being a first timer, I'm doing too much "internet research". After further consideration, I can at least install both races and the rear bearing without making things too difficult. I'll start redoing this in a few minutes...
Do you see any issues with my reasoning on the 0.020" clutch pack shim? The depth of the hub was 0.491", the feeler gauge reading averaged 0.021", which gives 0.470". Subtracting the Ford spec (?) of 0.455" leaves 0.015", which should be a bit on the tight side. BTW, the stock shim was 0.005" with the old clutches and steels.
I don't set the clutches like that. I put a shim in and assemble the differential without the springs, then stick it on an axle stub in a vice and turn it. If the resistance is too high I use a thinner shim. If it isn't enough then I use a thicker shim. When the resistance is where I want it then I put the springs in and call it good enough. You can't assemble one of these as tight as you do a Eaton Posi. If you get it too tight then it will pop and growl when turning a corner.
I don't understand why you used the loose fit bearings instead of putting the new bearings on to start with. There is no need to install and remove the bearings other than shimming the spacer, and you should be using your press to remove and install the pinion for that job, including removing the yoke. Yes, the preload will change when you change the bearings.
The marked pinion depth is almost always just a good place to start. It's always been off by around .003 when I tried to use it.
Don't know why I was stressing over not installing the new bearings, it was much easier than I thought. :sweat: BTW, my old "slip-fit" bearings worked great as a mandrel for pressing! Just 0.001" in shims makes a big difference with the solid spacer. I ended up with a 0.456" spacer and 27 in-lbs preload (0.455" was 40# and 0.457" was 0#). I originally thought my shim pack had 3 shims, but there were really 7 total, they were stuck together pretty good! Still couldn't finish the job, as the pinion seal in my kit was too large. QP is sending me the correct seal (they are great to deal with).
I've never tried that method of setting the clutches before. I know that the Ford Trac Lock is pretty touchy about the clutch preload. Just a little too tight and it's going to make noise.
I got my parts last night. This am, I added the slinger and pinion seal, did the lube, sealant, and lock-tite, rattled the pinion nut on and now have 42 in/lbs preload when it was previously at 27. So I diddled the shims (again) adding 0.001" and am now at 12 in/lbs. That's good. Set the pinion depth to 1.028" as per markings on the pinion, but it took 0.064" of shims (0.020"stock)! Got the clutch pack together but had a h$ll of a time compressing it while combining the two halves. Ended up using 5 of the old ring gear bolts with nuts & washers to compress it, but it seemed as if the OD of one half was larger than the ID of the other. Once together. it seems as if it will never come apart again. Pulled on the ring gear OK, put the carrier in the housing and set the backlash at 0.007". Tried running a pattern, but of course, the pinion was out too far. Took out 0.020" and still too far out. Took out another 0.018" and now it binds up part way through a rev. Checked the runout and the ring is 0.003" out. Then checked the carrier and it's got 0.012" wobble. The gap between the ring gear and carrier varies about 0.015".
Is this worth saving? I'm feeling I should just chunk it all and buy a locker...
So are you saying that the ring gear is not pulled all the way down on the flange? The 2 halves of the differential case are made to be a press fit, so that is not a problem. Did these 2 parts fot together completely?
IF yo decide to look into a locker take a look at the Grizley locker from Randy's Ring & Pinion. They claim to have fixed some of the problems that the Detroit Lockers had. Let me warn you in advance that they may have drilled the holes for the ring gear bolts too large. For some crazy reason they said that they drill them for 1/2 inch bolts instead of the 7/16 bolts that they should be drilled for. This caused me some problems with a Yukon Dura Grip.
The recess in the billet half was 0.200" while the factory half stands 0.260" tall. This leaves about a 0.060" gap between the ring gear and the outer edge of the billet (clutch) half with the gear pulled on all the way. I can check this with a feeler gauge and it varies some 0.015" around the perimeter. I may have warped one or both halves pulling them together with the old ring gear bolts and some nuts. It was really hard going and may take some brute force to get them apart again.
You say the case halves are a press fit, is that necessary? If I can get this thing apart, I was gonna pull the carrier bearings, chuck it in my lathe and turn the spider gear half a few thou to make the fit a bit easier. And of course, check the individual parts for runout...
I have an ex-NASCAR locker in my Maverick that I got on E-Bay for ~$250. My only complaint is the bang when making a RH turn. Left turns and the normal clacking don't bother me, but that blasted bang scares the h%ll out of every time!
Torquing the ring gear bolts should have pulled everything together, but you might have shaved off a little bit of metal when you pulled the halves together. This might have got between them and could be holding them apart. When you get ready to disassemble it put it in the press with the gear case facing down. Support it around the edge of the clutch case and stick a bar through the hole in the center through the axle gear and press against the cross shaft. That should seperate them.
Surprise! It all came apart just fine. There was a curl, but it seemed more like it was wedged in the side and not under. I took a tiny skim cut on the OD of the factory half. It's still a press fit but I can do it easily now.
Now the bad news... I gutted both halves and bolted them up empty, stuck it in the housing and put some preload on the bearings. This "new" billet half is 0.003" out of round and has 0.015" runout on the backside. The face where the gear mounts has 0.007" runout. The high spots seem to coincide, so it's prolly a poor machining job and didn't get caught in QC. Have e-mailed QP and am awaiting their response.
QP is sending me a complete empty trac-loc case in return for the bad billet hat. So, it's in a plastic tote box (on hold) for now while I tackle other things. Will post back when these parts arrive.
The new case QP sent is spot-on with < 0.001" runout and everything went together perfectly. I needed a 0.029" shim in the clutches and ended up with 0.033". My original pinion shim was 0.020". To get the called for 1.028" pinion depth I would have needed for over 0.060", so I started with 0.033". Set at 0.008" backlash and this is what I ended up with on my 1st attempt. Pix in order are drive - spot #1, drive - spot #2, coast - spot #1, coast - spot #2. Pattern seems a bit ambiguous, maybe cause the gears are new. Am I OK?
It doesn't look bad, but I don't wnat to say for sure because I can't read it very well. Use a few drops of oil on the teeth and run it through several more times so that it wipes off more of the compound and leaves a more clear pattern.
Haha, that was with oil! this time I used some WD-40 and smoothed out the compound, pix are: drive - spot #1, drive - spot #2, coast - spot #1, coast - spot #2.
Looks pretty good. It's hard to tell sometimes because I haven't seen what more shim looked like and what less shim looked like. I like to see it both ways before making a decision, but if you think this is the best that you can get then run with it.
I would love to play with the shims and see, but after lifting this thing in and out of the vice and torquing bolts, my rotator cuff is saying NOOOO! Several others I know have all said it looks OK to run, so I'm gonna leave it...
Had to tear into it anyways. ain: After a vivid memory flash, I realized I put the clutch hub thrust washer between the hub and gear instead of between the hub and case. While I was torquing the ring gear bolts, it started slipping around 45 ft-lbs. I never realized during the first assembly, it never slipped at all, even at 70 ft-lbs. Will this "slippage" get better or worse with the addition of gear lube, friction modifier, and normal heat?
So, after reassembly and not touching the pinion, I set the backlash at 0.008" again and got this pattern. I'm out of paste, so I scraped some off and mixed it with white lithium paste. This pattern looks more pronounced, but different than the first? May not be a good read with the homemade paste...
If that's an accurate pattern then it looks great. That's almost complete tooth contact. I don't think I have ever seen one with that much contact area before. May just be the grease that you used.
The clutches should be tight enough that you can torque the ring gear bolts and not ever feel anything slip. I've had to take these apart and remove shims because they locked up too much.
I thought I'd read somewhere that 45# breakaway was the factory setting. So you think I should add more shims?
What's a good trick for installing the ring gear on the case? I've had zero luck with my press (it always wants to go on crooked). I've been using 3 old Buick head studs with spacers to pull it on far enough to get the bolts started, but my shoulder really doesn't like all that pulling. You think Advance or Autozone would have the pattern compound?
You can get the gear marking compound at many GM dealers. It's hard to use a press and get the gear on straight. You have a pretty good way of doing it. I don't know why your clutches are not holding. The springs should be enough to keep you from being able to turn it. I don't set the shims the way you are doing it.
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