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Inside the "Super 8.8" Rear End

boB

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Good question. Why locktite and not a teflon pipe sealant or tape?
My guess (and that is all it is) is that with the vibration at the diff we may want something that seals and hardens to prevent the plugs from coming out. I used teflon tape and if I do it again I will use new plugs or non-teflon pipe sealant.
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JohnVallo

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I noticed on the Pinion there is a number written by hand right in the middle where the crush sleeve sits. In my case it says 06. Could it be a hint for the pinion depth? Maybe + or - 0.06?

The other thing is when i set the pinion preload i had a good amount of break away torque. It was very hard to turn by hand and it went above the scale of the beam style torque wrench. Once it was moving, i was about 25 lb-in. What i read, this should be okay with new bearings. Is it normal that the break away torque is so much higher than the rotational torque? Maybe i haven't oiled the sealing enough?

And the last question, what about the Diff bushing inserts? Do you put them back in?
I experienced the same 40-65 mph whine when taping the Gas to hold the speed.
It immediately disappears when stepping on the Gas or completely letting off the gas.
Is this because of the bushing inserts or is this a setup thing? Can you get rid of the whine and have them installed?

thank you
Alex
Alex,
I was told that Ford & Ford Performance does not mark their Pinion gears in regard to pinion depth or shims. On OEM Ford Pinions Gears I have not seen them marked.
Some aftermarket R&P manufactures do mark the pinion, but it is usually on the face of the pinion head.
Here is a YUKON aftermarket 4.88 pinion.
IMG_0174-a.jpg


Regarding the Pinion preload question:
Yes your preload is somewhat high. With New bearings, I like the running preload torque to be between 12-20 in lbs. With re-used bearings, around 10-15 in lbs.
Also remember that if you are recording pinion torque with the differential in place, the differential bearings also have a preload, so you are actually measuring Both preloads.
The breakaway torque will usually always be more, but after breakaway, not really hard to turn by hand, (only mild resistance)
Being the preload is on the tight side, I would do an extended break-in, not driving the car fast for at least a couple hundred miles.

Regarding the Bushing Inserts:
If you are referring to the Poly stiffening inserts,
They will definitely magnify Noise/Whine from the Ring & Pinion.
If you take the inserts out and still have noticeable whine, then that is probably a setup issue.
 
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bankyf

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Alex,
I was told that Ford & Ford Performance does not mark their Pinion gears in regard to pinion depth or shims.
Some aftermarket R&P manufactures do mark the pinion, but it is usually on the face of the pinion head.
Here is a YUKON aftermarket 4.88 pinion.
IMG_0174-a.jpg


Regarding the Pinion preload question:
Yes your preload is quite high. With New bearings, I like the running preload torque to be between 12-18 in lbs. With re-used bearings, around 10 in lbs.
The breakaway torque can be more, but not really hard to turn by hand, (only mild resistance)
Being the preload is on the tight side, I would do an extended break-in, not driving the car fast for at least a couple hundred miles.

Regarding the Bushing Inserts:
If you are referring to the Poly stiffening inserts,
They will definitely magnify Noise/Whine from the Ring & Pinion.
If you take the inserts out and still have noticeable whine, then that is probably a setup issue.

Pinion depth shim size requirement is a function of the housing and how it was machined and is not determined by the ring and pinion. This is why you won't typically see pinion shim sizes stamped on Ford gears. In almost every case you can reuse the original shim unless you have an unknown housing. Ford has a tool set to determine the pinion shim size, but the entire setup runs close to $1000 for each model of differential. I recently built a Super 8.8 from all new parts and had to upgrade my set for the super 8.8 specific parts

As for preload, the OEM specs on these super 8.8s is quite a bit higher than most of us are use to with older Ford diffs. Ford calls for 22-34 lb-in, with the higher end being more appropriate for new bearings.
 

hot rod

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Hey, thank you for your answer.
Sorry it took me a while to respond.

So no worries about the handwritten numbers on Ford Performance Pinions, okay.
Is that pattern on the pinion bearing normal? It has just a few miles on it.

IMG_6219.jpeg


So, I'm not an expert on setting up Ring and Pinions. I swapped from FP 3:55 to 3:73 gears.
The Original Pinion shim was 0.33" i played a bit with different shims and endet up with 0.31".
No noise, but the OE bushings are good in masking any noise.

Here are some pictures, what do you guys think?

IMG_6217.jpeg

IMG_6216.jpeg

IMG_6214.jpeg

IMG_6213.jpeg

IMG_3179.jpeg

IMG_3178.jpeg
 
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JohnVallo

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Hey, thank you for your answer.
Sorry it took me a while to respond.

So no worries about the handwritten numbers on Ford Performance Pinions, okay.
Is that pattern on the pinion bearing normal? It has just a few miles on it.

IMG_6219.jpeg


So, I'm not an expert on setting up Ring and Pinions. I swapped from FP 3:55 to 3:73 gears.
The Original Pinion shim was 0.33" i played a bit with different shims and endet up with 0.31".
No noise, but the OE bushings are good in masking any noise.

Here are some pictures, what do you guys think?

IMG_6217.jpeg

IMG_6216.jpeg

IMG_6214.jpeg

IMG_6213.jpeg

IMG_3179.jpeg

IMG_3178.jpeg
Looks like pretty heavy wear on that pinion bearing, What does the Cup/Race look like ?

Interesting color on the gear marking compound, What is That ? , but pattern looks OK
 

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hot rod

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The Cup looks the same.
So maybe next time a bit less preload.

IMG_6351.jpeg


Gear marking compound is „Diamant - red“ it is a German manufacturer.

IMG_6352.jpeg
 

Whitedevil95

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Such great info here! I just recently picked up a Iron 3.55 gear pumpkin from a 2019 GT Auto. Looking to swap in to my Centri 2017 GT with a 3.15 gear set.
 

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Hey @JohnVallo,

I'm putting together an aluminum 8.8. I need to retorque the bearing end cap bolts. The only number I can find is 77 ft lb, but I think that might be the iron housing. So I figured you're the one to ask.

What's the bearing end cap torque in an aluminum Super 8.8?
 

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I found the 71 FT/LBs in my manual bit it did not specify for iron or aluminum so was not 100% sure.

BD
 

TeeLew

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