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Differential Flanges - Any Experts?

JohnVallo

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Removing the outer pinion bearing race (from the front) would be nearly impossible with the pinion shaft still there. It's hard enough to punch it out from the rear. And it would take longer than diving in the deep end of the pool.
To replace the crush sleeve, you will need to remove rear cover and take out the diff.
I think a lot of guys chance using the old crush sleeve. It definitely is a risk.
For more info:
Inside the "Super 8.8" Rear End | 2015+ S550 Mustang Forum (GT, EcoBoost, GT350, GT500, Bullitt, Mach 1) - Mustang6G.com
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Brian O

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Thanks John. That seemed like the only conclusion, but I hoped for a "trick" that I was not seeing.

Thanks again.
Brian
 

Brian O

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Removing the outer pinion bearing race (from the front) would be nearly impossible with the pinion shaft still there. It's hard enough to punch it out from the rear. And it would take longer than diving in the deep end of the pool.
To replace the crush sleeve, you will need to remove rear cover and take out the diff.
I think a lot of guys chance using the old crush sleeve. It definitely is a risk.
For more info:
Inside the "Super 8.8" Rear End | 2015+ S550 Mustang Forum (GT, EcoBoost, GT350, GT500, Bullitt, Mach 1) - Mustang6G.com
Thanks for that link. I do not have time right now to read the whole thing. That seems to hold all the info I had been looking for.... I just never found it.

Realy appreciate that

Brian
 

Crackerjack17

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This all seemed easy enough to me. I purchased a used 2018 differential (pumpkin) with the gearing I desired, and was simply going to swap to a new pinion/driveshaft yoke to fit my 2017 driveshaft (I would then have two complete differentials with different gearing available). All the parts are present and ready for the swap. I checked the turning preload on it before removing the yoke. Removed it, removed the bearing, ... all looks good. Except the crush sleeve is below the race. I can not figure how to remove the race (and get too/install new crush sleeve) without a full Differential teardown. No puller I have will fit between the old crush sleeve and race to get a hold of it.
I have searched for a tool small enough to get at this race to remove it (with pinion shaft still in place), .... and no luck.

Several people on this site have talked about just swapping it, but how the heck to you change the crush sleeve without diving completely into the deep end of the pool? I am considering finding a shaft shim and placing it on top of the old crush sleeve and then reassemble and simply further crush the old crush sleeve (I mean a real thin shim).

Has anyone done this? How have you handled this? Any input/advice will be appreciated.

Thanks ...Brian
I recently rebuilt my diff(3:73 torsen) and swapped in 3:31 gears. I changed all the races, bearings and seals. I don't know how you change the crush sleeve without disassembling the entire diff. And it was a lot of work. You have to squeeze the case to get the diff out. AND... when I went to set the preload on the flange I could not for the life of me get the new "crush" sleeve to crush! I even used an impact wrench which obviously isn't advised and it wouldn't budge. So, I simply put the old crush sleeve back in and tightened the nut, checked the torque and it came out to spec. Been in my car for over 1k miles and working perfect. quiet and no noise. I'm driving on the street hitting 14-15 psi every time I drive it!

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Brian O

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Thanks

I took some time. Read everything I could find. The link John provided was quite a wealth of information (as usual).
I ordered some shims to install above the old crush sleeve. They arrived too big to do the job. I also had a concern (adding a shim) the gear fluid would be hampered from flowing to/through the front bearing.
In the end, I did what you did. I reassembled it. I had good data (rotation torque prior to disassembly). It was unnerving at first, with shaft vertical .... it would not turn smoothly for a long time as I tightened the nut. I kept wondering if I missed something. But as I lifted on the shaft, it turned smoothly. That of course, all went away as I drew the shaft tighter (and UP in my case).
Took a while, kept checking rotation. I got the rotation torque exactly as it was prior +/- 0.

I will not install it for a while. The car is presently wearing a 3.73. The new one is a 3.55. Looking forward to trying it out, but I will leave it be for an upcoming autocross. Besides, it is just to pretty to bolt under a car right now.

Brian

Thanks for the info.

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kapiteinlangzaam

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Finally completed my swap today.

EB 3.31 diff into my 3.73 GTPP1 MT82

Used the famous companion flange, worked perfectly.

So happy with the 3.31s, suits boosted applications so much better.

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s550gtbase

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Finally completed my swap today.

EB 3.31 diff into my 3.73 GTPP1 MT82

Used the famous companion flange, worked perfectly.

So happy with the 3.31s, suits boosted applications so much better.

PXL_20230612_083132937_copy_1024x1023.jpg


PXL_20230612_083126311~2_copy_1024x1308.jpg


PXL_20230612_075240881_copy_1024x1360.jpg
Can you tell me what is the " Used the famous companion flange, worked perfectly. "? What part is this?

Thanks
 

kapiteinlangzaam

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Spikertg

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Also, PSA: GT350 diffs also have a different, and smaller flange (looks like the same as the 18 manual one you posted here) that I am not able to bolt up my 2015 manual driveshaft too. Bolt circle and flange ID are smaller. This came as a real surprise bummer today for me.
This is all very interesting I am in here trying to learn what I need to put a 3.15 dif in my 18gt cause I’m at 800whp and I have a 3160 swap out of a gt350 and I want more spread and the Ability to hit 200 in 5th so no overdrive. What I find interesting is I have my stock 3.55 manual dif and all I needed to bolt up the 3160 was a stock gt350 driveshaft? But y’all did say the 18+ and gt350 had 110mm and 93mm spacing so does make since
 

Spacexguy

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Good day all. I have a question for the group. I'm seeing a lot of results for FR3Z flanges, but I have one that has FR3W stamped on it and dont see anything online for it and its applications? I got this diff in a package deal with a mt82 and decided to rebuild it. Any insight from the flange experts here would be more than appreciated. I've attached a picture of it. Many thanks!!

Screenshot_20250428_170950_Photos~2.jpg


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JohnVallo

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Good day all. I have a question for the group. I'm seeing a lot of results for FR3Z flanges, but I have one that has FR3W stamped on it and dont see anything online for it and its applications? I got this diff in a package deal with a mt82 and decided to rebuild it. Any insight from the flange experts here would be more than appreciated. I've attached a picture of it. Many thanks!!

Screenshot_20250428_170950_Photos~2.jpg


Screenshot_20250425_221153_Photos.jpg
A lot of times the stamping number will be Very Similar to the actual part number.
Proper identification will be from:
Year, Model
or Measuring Inside Diameter at the flange's mating surface, (110mm, or 113mm)
Basically only 3 flanges were used for the 2015-Up Mustangs & Shelbys

2015-2017 MT82 Manuals Only 113mm
2015-2017 Automatics, and All Shelby GT350's 110mm
2018-Up (All, These all were the improved small Automatic (110mm version)
 
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Spacexguy

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A lot of times the stamping number will be Very Similar to the actual part number.
Proper identification will be from:
Year, Model
or Measuring Inside Diameter at the flange's mating surface, (110mm, or 113mm)
Basically only 3 flanges were used for the 2015-Up Mustangs & Shelbys

2015-2017 MT82 Manuals Only 113mm
2015-2017 Automatics, and All Shelby GT350's 110mm
2018-Up (All, These all were the improved small Automatic (110mm version)
Ah! So rule of thumb is always measure the inside diameter, rather than go by part number. Thankyou!!
 

Spacexguy

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A lot of times the stamping number will be Very Similar to the actual part number.
Proper identification will be from:
Year, Model
or Measuring Inside Diameter at the flange's mating surface, (110mm, or 113mm)
Basically only 3 flanges were used for the 2015-Up Mustangs & Shelbys

2015-2017 MT82 Manuals Only 113mm
2015-2017 Automatics, and All Shelby GT350's 110mm
2018-Up (All, These all were the improved small Automatic (110mm version)
Just measured, definitely 113 mm.
 

mohadnuj111

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Does driveshaft bolts size matter? I am having an issue right now is that i bought a new dynotech one pice driveshaft and they sent me the 15-17 version and my car is 2018.

After contacting them they sent me an +18 pinion flange to replace it. My question is will the bolts included with the driveshaft fit?

also, does the trans flange on 15-17 is same as +18?

thanks
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