Pinion Nut Torque With Solid Spacer

[SteveWK]

Bad Company: Thanks for that information. I think it will be very helpful. I read in one of the pdfs (snoppy49) that you're suppose to add 0.006 to each side of the carrier bearings after setting it all up. I didn't know that was to be part of a single solid spacer. Gears push against each other in different directions depending on the angle of the interface, and if one of those gears is floating enough, e.g. not enough bearing preload, I can see how that would be a problem.

I really appreciate all the input.

 

[Snoopy49]

Notice that the factory uses Maximum Strength Retaining Compound Loctite® 638™ between the ring gear and carrier?
Checkout step 17 on page 12.

https://www.svtperformance.com/foru...1/?temp_hash=6c40fba15b31a919856346e648e896e9

 

[SteveWK]

I doubt my installer did that - LOL

 

[SteveWK]

So what is that to prevent? Any slop between the ring gear and the carrier?

 

[Snoopy49]

My guess is that Ford determined the bolts needed some additional help when it came to clamping down on the rotational slippage between the ring gear and the carrier under the torque developed by this engine. Less chance of the ring gear bolts coming loose and shearing.
And it may dampen noise.

 

[SteveWK]

Snoopy49, danke, always

 

[Bad Company]

@Bad Company great information.

I wonder which is more important. The one piece cast shim Vs a stack of shims or the additional thickness the one piece cast shim provides. Like after a speed shop sets bearing pre-load per Ford Racing instructions they then take the pinion gear out and add another 0.003" shim, would this yield similar results as using a one piece cast shim.

I'm talking about the bearings for the center section, not the pinion bearings. First you set the pinion depth using shims, once this is done then you set the pinion bearing pre-load using the crush spacer.

The side carrier bearings pre-load can only be set by using the over dimensional one piece shims. The other thing that I remember in the service manual is once you install the oversized shims you still have to turn the complete assembly to measure the additional torque required to turn the complete assembly. Once you have that measurement you must subtract the amount of torque that it took to turn the pinion on its own to arrive at the amount of pre-load you now have on the carrier bearings.

This is a long drawn out process to rebuild one of these rears correctly. Throw in a set of bearings that are treated with MicroBlue Racings anti-friction treatment and things get complicated very quickly due to the fact the stock bearing pre-load requirements in the factory service manual are wrong with this bearing treatment

 

[Bad Company]

Bad Company: Thanks for that information. I think it will be very helpful. I read in one of the pdfs (snoppy49) that you're suppose to add 0.006 to each side of the carrier bearings after setting it all up. I didn't know that was to be part of a single solid spacer. Gears push against each other in different directions depending on the angle of the interface, and if one of those gears is floating enough, e.g. not enough bearing preload, I can see how that would be a problem.

I really appreciate all the input.

I didn't look at the PDF and was trying to remember. If Snoopy's link to the PDF states 0.006" then that is what is required as long as you don't use old bearings or anti-friction treated bearings.

Yes without the carrier bearings having pre-load the center section with the ring gear is always going to push away from the pinion gear. This changes the contact pattern between the pinion and ring gear and induces gear whine immediately

 

[Bad Company]

My understanding of the retaining compound is it fills all surface irregularities between the differential and ring gear matting surfaces for a much higher contact area between the two surfaces. This would support the ring gear from trying to move or flex as power is applied to it from the pinion gear. It also would marry the two parts to make them one to keep both pieces from deflecting as much under load if they were only bolted together.

 

[Bad Company]

Another problem I found is the shim kits from Ford Racing have a ridge on them on the edges. This comes from being punched out of a piece of shim stock. The reason I caught it was the fact I measured each shim individually to add up what I needed to set pinion depth, but after I would stack the shims together the measurement of the stack was higher than what the individual shims added up to mathematically. Each shim had roughly a 0.001 to 0.002 ridge on them. I took fine sand paper and sanded this off by laying the sand paper of a piece of glass for a flat surface and gently sanding the lip/ridge off without changing the overall thickness of the shims.

If your installer doesn't catch this I believe this will cause a whine after a few miles of driving or a hard launch as this ridge on the shims is flattened out by the torque of the engine and the bearing pre-load, pinion depth and gear backlash change from the original installation measurements. Ford Racing is purchasing the shims they sell in the kits from Ratech, as I found Ratech stamped into one of the shims.

 

[SteveWK]

Thanks for the additional info Bad Company. The 3.73s I have in the car probably have 500 miles on them. I'd really like to find out what the problem is with my current setup before moving on to 4.10s. Pulling the diff cover and removing the carrier bearing shim stacks and replacing them with 0.006 over solid shims sounds relatively easy. If fixing my problem requires a complete rebuild, I'll just put the 4.10s in then.

What Ford specific tools did you buy to install your gears? I've seen pictures of the pinion depth tool, but don't know if that tool works only with OEM gears or if it works with both OEM and Ford Performance gears.

Steve

 

[Cman01]

Notice that the factory uses Maximum Strength Retaining Compound Loctite® 638™ between the ring gear and carrier?
Checkout step 17 on page 12.

https://www.svtperformance.com/forums/attachments/differential-case-and-ring-gear-—-traction-lok-pdf.1488441/?temp_hash=6c40fba15b31a919856346e648e896e9

I think it would be proper to use that Loctite compound if you were reusing your ring gear bolts to bolt down your new ring gear.

With my gear install I purchased the M-4210A kit and it comes with new ring gear bolts that has locking compound already on the threads + the new pinion nut also has locking compound.

I will spend the next few days looking over this procedure on my cd manual and take notes down, when I head over to the gear place for my install I will share the info on the cd with my installer. I'm waiting for it while they do the install and I plan to be near the car so I can keep an eye on the install process.

 

[Snoopy49]

Cman01,
Ford used the Loctite compound between the ring gear and carrier.

Apply a one-eighth inch bead of maximum strength retaining compound on the rear face of the ring gear in the pattern shown.

 

[Cman01]

Oh ok I get it that's where you use the locking compound I thought it was just on the threads of the bolt.

I will add this step to my notes for the installer.

 

[Bad Company]

Thanks for the additional info Bad Company. The 3.73s I have in the car probably have 500 miles on them. I'd really like to find out what the problem is with my current setup before moving on to 4.10s. Pulling the diff cover and removing the carrier bearing shim stacks and replacing them with 0.006 over solid shims sounds relatively easy. If fixing my problem requires a complete rebuild, I'll just put the 4.10s in then.

What Ford specific tools did you buy to install your gears? I've seen pictures of the pinion depth tool, but don't know if that tool works only with OEM gears or if it works with both OEM and Ford Performance gears.

Steve

You've driven the car enough miles with the 3.73 gears that you'll never get them to be quiet. The reason for this is you've already put a wear pattern in the surfaces of the ring and pinion gear. To change the pre-load and backlask with the correct shims is to change the position of the two gears in relationship to each other. This means the wear pattern you've already established wont be in the exact same position of the gears. It will be noisy no matter what you do from this time forward.

As for the tools required I found a used Ford Rotunda ring and pinion install tool kit on Ebay for the 7.5" and 9" rear axle assemblies. This kit has quite a few of the same tools required for the 8.8, the few it didn't have I was able to buy individually to have the complete tools required to build the 8.8. Ford has discontinued making these tool kits or selling the parts individually. OTC was making these tool kits for Ford and selling them under the Ford Rotunda name. OTC sells the tools individually, unfortunately this is an expensive way to purchase these tools now if you are looking to buy them new.

Here is a link to a Ford Racing Installation Instruction PDF for the 8.8 gears. On page 8 there is a complete list of the tools required to set the pinion depth correctly. I Googled these tool part numbers to find the tools for sale used. I was lucky to find an old complete Ford Rotunda tool kit for the 7.5" and 9" rears on Ebay with most of these tools. Looking at it I doubt it had been used more than a few times. The few tools it was missing to do the 8.8 I was able to purchase on Ebay or new from OTC to be able to do my 8.8 rear.

https://performanceparts.ford.com/download/instructionsheets/FordInstShtM-4209-8.pdf

The Ford Racing gear sets and the factory gear sets are made in the same factory to the same specifications and tolerances. This means the installation of both gear sets is exactly the same and follows the exact same installation instructions for setting pinion depth, ring gear backlash and bearing pre-loads.

Now any aftermarket gear set sold by any other company is NOT made in the same manner, which means the factory installation tools won't work for setting pinion depth correctly. To do this with a Richmond or Motive gear set you have to set the pinion depth the hard way. This means you'll be mocking it up a number of times with different pinion shims to establish the correct pattern on the gears.

Looking around the internet I found this company that is selling the tools for setting pinion depth of Ford or Ford Racing gear sets. One is an aftermarket set and the other I believe is the OTC kit

8.8-Inch Ford Ring and Pinion Installation Set Alt ST-S911

205-8.8 8.8-Inch Ring and Pinion Installation Set

Don't ask me about the quality of the Stallion tool kit, which is significantly cheaper than the OTC kit, which is the same tools Ford sold under the Rotunda tool name.

 

[Snoopy49]

To bad a Dana 60 wouldn't fit. I have all the setup tools for that rearend.

 

[SteveWK]

Bad Company thank you for the additional information. I have lots of home work ahead before I tackle this problem. It might be a month or two before it is all resolved. Another forum member and I will be removing the entire rear end and performing surgery on it . I will document this extensively on the forum with pictures to the nth degree and hopefully it will help someone else in the future.

 

[Mojo88]

.....I will document this extensively on the forum with pictures to the nth degree and hopefully it will help someone else in the future.

Yeah man, thanks! This info will be a big help. Much appreciated!

 

[RedVenom48]

When I had the factory 3.73 gears replaced under warranty for whining, the second I did a burnout and launched at the strip they whined loud and hard. This was with the factory UCA, mount and diff bushing. BMR LCAs with their hybrid rubber/poly bushing.

When I replaced my gears myself, I opted to go for the Ford Racing 4.10 set. I pressed off the ring gear and found NO 638 between it and the carrier. Ford tech didnt use it. I made sure to use the 638 as specified in the Ford Racing instructions during reassembly. Its made a difference. I added the Moser (ARP 2000) carrier cap stud kit and a Ford Racing G2 diff girdle cover during reassembly so it reinforced the diff too. I also redid my suspension with a Rod end BMR upper, BMR poly solid diff bushing, and BMR rod end lowers and relo brackets. Its a whole lot of solid in my suspension compared to when I was running the 3.73s.

3 aggressive burnouts and quarter mile passes on the setup and only a slight whine at 70 mph. Not audible any other speed or load. It may get louder the more burnouts and passes I make but compared to 3 passes with the 3.73s, its a night and day difference.

These 8.8s will just be noisy. That simple. 3 link rear end has more to do with the noise transfer, but I think there is something in the harmonics of the 3.73 cut that makes them whine the most.

 

[Snoopy49]

These 8.8s will just be noisy. That simple. 3 link rear end has more to do with the noise transfer, but I think there is something in the harmonics of the 3.73 cut that makes them whine the most.

I wonder if this is the reason Ford added the dampener weights to the end of the axle housing?