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Discussion Starter #1
Ok, kinda need help here fast so here's the deal. Rebuilding a trac loc and putting 3.73's in. The question I have is this. The shim that goes on the pinion gear shaft, between the gear and the bearing...how do you know which to put in. The ford manual doens't say, although it says measure it and then that's all. Right now, we're thinking to put 0.023" of shims in, as this is what the old 3.27 pinion gear has. It would be good to know what to put in, as it wouldn't be much fun pressing the bearing on and off trying to find the right shims. And we've only got 2 crush spacers as well. Thanks for any input.

Joe
 

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I usually start with the shim that was on the gears. If the gears are new it makes it more difficult to figure out. Thats is when it is nice to have a dummy bearing to measure with so you only have to press the bearing together once.
Alan
 

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Discussion Starter #3
Thanks Alan, I was kind of figuring it would make it a bit more confusing to find the correct shim. I suppose I could press the old bearing off the pinion gear and open it up a little so we don't have to press it on and off, that might make it easier.

Joe
 

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Yes use a good used bearing(not the one you are going to install). Hone it out until it slides on. That material is very hard so it is difficult to machine. Grinding stones work well,but don't last long unless you cool them. Sandpaper is worthless. A friend of mine did one with a few brake hones and a drill.
Thank god for carbide.
Alan
 

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hmmmm, putting a new pinion in without checking pinion depth? Sounds like a set of gears that is going to be short lived. Let me guess, you don't have a backlash gauge also, do you?

The only thing I can tell you is to measure the thickness of the pinion gear, and add the amount of factory shim, then measure the new pinion, do some math, and figure out your shim thickness from that. That'll get you in the right ballpark at least, that's how I normally start, but I use a pinion depth gauge, which you really need to set up a set of gears correctly.

Setting up gears isn't a simple, bolt in procedure that you can do in your garage with a Craftsman tool set.
 

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Discussion Starter #6
We've got all the tools, we were just unsure about how to get it close the first time without having to press the bearing on and off a bunch of times. Neither of us has done a rear end before...kind of need a place to start, as does anyone. Now that I know what is going on (somewhat) I think we'll be ok. I'm not planning on dropping the rear end in for awhile yet, so we've got plenty of time to get everything right. Thanks

Joe
 

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Rich95XR7 said:
The only thing I can tell you is to measure the thickness of the pinion gear, and add the amount of factory shim, then measure the new pinion, do some math, and figure out your shim thickness from that. That'll get you in the right ballpark at least, that's how I normally start, but I use a pinion depth gauge, which you really need to set up a set of gears correctly.

Setting up gears isn't a simple, bolt in procedure that you can do in your garage with a Craftsman tool set.
This is how I set my pinion depth. Luckily, FMS gears are machined very precisely, which makes the job much easier. I was able to reuse the shim from the old pinion on the new one. Aftermarket gears are like a box of chocolates...

Adjusting the backlash really isnt too difficult, just time consuming. Without a set of depth guages I wouldnt attempt swapping gears by myself. Too much risk of making a mistake. That said, I have about 16k on my 3.73's with no issues at all.
 

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whitecoug said:
Ok, kinda need help here fast so here's the deal. Rebuilding a trac loc and putting 3.73's in. The question I have is this. The shim that goes on the pinion gear shaft, between the gear and the bearing...how do you know which to put in. The ford manual doens't say, although it says measure it and then that's all. Right now, we're thinking to put 0.023" of shims in, as this is what the old 3.27 pinion gear has. It would be good to know what to put in, as it wouldn't be much fun pressing the bearing on and off trying to find the right shims. And we've only got 2 crush spacers as well. Thanks for any input.

Joe
Are the gears motorsport or ford? If they are look to see if there is a +.00x or -.00x on the old or new pinion. If there is not one then it will be ok to use the old shim (this is assuming the numbers didnt wear come off on the old pinon.) I do recoment getting someone with a set of bearing depth gauges to do this for you.

Josh
 

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Discussion Starter #9
Thanks for all the replies guys. We ended up needing quite a bit of shim to get the new pinon even close (they were both Ford gears, btw). Another friend stopped by and they finished it for me (the other does his own rears). So now I'm just waiting for the weather to get a little warmer to drop the rear end in...or should I say lift it in...and we'll see how she works.

Joe
 

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Discussion Starter #11
Good find Alan...wish I would have had that last week, but it may come in handy for the next one.

Joe
 

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Re-started Thread I know.....

OK...

Here's the scenario...

I'm not replacing gears, I'm keeping the 2.73's that are in the SC 8.8 rear. All I'm doing is rebuilding the pumpkin.

Here's the problem...

I managed to get all bearings replaced, re-used the factory shims in ALL locations. When I am trying to set the pinion depth, I get SO MUCH end play in the pinion shaft that I don't think I'm doing it right.

My question is this, How do I get the pinion nut set to the right tightness to measure the bearing torque so I can determine if the factory shim is the right one to use with these new bearings? I've not done this before, but I DO have all of the dial indicators to measure backlash so I'm not worried about that. I'm just worried about the pinion depth.

Please Help.
 

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joshbea6 said:
OK...

Here's the scenario...

I'm not replacing gears, I'm keeping the 2.73's that are in the SC 8.8 rear. All I'm doing is rebuilding the pumpkin.

Here's the problem...

I managed to get all bearings replaced, re-used the factory shims in ALL locations. When I am trying to set the pinion depth, I get SO MUCH end play in the pinion shaft that I don't think I'm doing it right.

My question is this, How do I get the pinion nut set to the right tightness to measure the bearing torque so I can determine if the factory shim is the right one to use with these new bearings? I've not done this before, but I DO have all of the dial indicators to measure backlash so I'm not worried about that. I'm just worried about the pinion depth.

Please Help.
Sounds like the sleeve isn't crushed all the way to me get an inch lb torque wrench and crush the sleeve without the carrier installed until you get about 16-20 inch lbs of resistance. The sleeves are hard to crush eat your spinach first.
Alan
 

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We even tried using the original crush sleeve, and still get either NO ability to rotate the pinion, or WAY TOO MUCH pinion play.

Based on what I have read, I thought you weren't supposed to use the crush sleeve when setting the pinion depth?
 

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joshbea6 said:
We even tried using the original crush sleeve, and still get either NO ability to rotate the pinion, or WAY TOO MUCH pinion play.

Based on what I have read, I thought you weren't supposed to use the crush sleeve when setting the pinion depth?
You have to use the crush sleeve when setting preload...pinion depth is not set by the sleeve it is set by the shim which should be measured using a pinion depth gauge.
Alan
 

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Alan's right...pinion bearing preload and the pinion depth shim are completely unrelated. The wrong shim will ruin your pinion depth, not your bearing setup. You're getting endplay because, as Alan stated, you haven't crushed the sleeve yet. You can't turn it with the old crush sleeve installed because it's already crushed, and you're tightening the bearing to the race, resulting in excessive preload and your inability to turn the pinion. Figure out your pinion depth shim first, snugging the pinion nut without a crush sleeve in place. Once you figure out what shim you need to set your pinion depth, install the crush sleeve and set bearing preload. Again, realize the two things, pinion depth and pinion preload, are completely unrelated.

Mike
 

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My pinion depth was easy. Ford gear was marked .0299 which means .030 shim. The factory gears were like new so I got a baseline reading of pinion depth from the factory pinion gear to the housing flange. [The actual depth on aftermarket gears is from the center of the carrier bearing to the pinion face] Installed the new .030 shim, checked the depth against my baseline and acheived perfection. I hammered the crush sleeve with an impact then snuk up on the final preload setting with a breaker bar. You have to really know your impact because once it starts crushing it goes easy. I had an extra crush sleeve or I probably wouldn't have used the air wrench :) Backlash was real loose with the original carrier shims- .014...thought about swapping them to get a 'lil tighter but still within spec so what the heck :rolleyes:

You can get a hd pinion shim kit from frpp that goes under the race vs under the bearing. Waste of $$ , though I would have bought one if they had it in stock.

BTW I used a smaller diameter STEEL driveshaft from an old Marquis with the tbird transmission yoke and had it balanced...no driveshaft vibes but it hasn't been over 100 mph. The driveshaft was thick walled and came from a car that wasn't ever forklifted.
 
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