Ford 9.75 Carnage and Help needed.

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Jun 11, 2013 | 01:38 PM

peppermrj

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From: Southwestern Pa.

Ford 9.75 Carnage and Help needed.

1998 Ford F150 XLT Scab 4X4
5.4L engine Prairie Tan
9.75 Limited Slip with 3.55 Gear set

Short story, I need a way to calculate the pinion depth.
I am installing a replacement OEM 3.55 Gear set without any checking distance markings.

The original shims were destroyed when the inner pinion bearing failed. The bearing itself was unrecognizable except for the outer race. Normally I would simply hone the inner pinion bearing's inner race until the bearing could be slip fit on the pinion shaft and go from there. See Pics.
I fear that if I have to install and remove the inner pinion bearing several times to accommodate shim addition/deletion that it would be ruined.

Any advice would be greatly appreciated.

Jun 11, 2013 | 02:01 PM

peppermrj

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From: Southwestern Pa.

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Jun 11, 2013 | 02:05 PM

peppermrj

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Was not even sure what this was upon disassembly. The only thing I could not find was the Pinion's innner bearings inner race!

Jun 11, 2013 | 02:15 PM

peppermrj

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From: Southwestern Pa.

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Jun 11, 2013 | 02:22 PM

peppermrj

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From: Southwestern Pa.

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Jun 11, 2013 | 02:25 PM

peppermrj

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Jun 12, 2013 | 11:47 AM

70f100longbed

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From: Raleigh USA

HOLY DIFF CARNAGE BATMAN!!! That thing must have cried and moaned for a LONG time! There are several special tools needed to select the proper pinion shim and assemble the diff. I would not hone the bearing so it slides on the pinion or else it will spin on the pinion when its put together and damage the new gears. The bearing needs to be pressed on. My advice is get it towed to the dealer or someone that has built a lot of ford diffs for the best results.

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Jun 13, 2013 | 02:43 AM

peppermrj

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From: Southwestern Pa.

Wish it would have. 1 long fast trip down the Pennsylvania turnpike, when I hit the toll booth it certainly was.

I normally will hone the inside race of the Pinion head bearing to a slip fit only for setup of the new Pinion's depth. It would then be replaced by the new bearing and race along with the tail bearing, carrier bearings, wheel bearings, and seals.

However not this time. Pinion depth gauges are rather expensive and complicated even for most pros.

Ratech make a very accurate and affordable Pinion Setting Tool at around $30.00 but not for the 9.75.

Randy's ring and pinion Sells Set up bearings that are prehoned, nonreturnable and also a bit pricey.

Looks like I will end up buying another bearing and honing it for the setup. My math and machinist skills are not what they used to be. Just cant seem to work out the measurements inot something useable. My hard drive is too dependent on the one in the laptop. L O L

Thanks for your thoughts.