8.8 Gear Swap "need Help"

Cobraj93

Member
May 3, 2016
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Hi All! I am performing a gear swap in my 93 GT. I am replacing a 3.73 with a 4.10. (Both Ford Racing gearsets). Also replacing diff with Detroit Truetrac and 31 spline Moser axles. All bearings, races, and seals replaced. My question is with the gear wear pattern I am getting. It seems to be wiping the marking compound off of the complete tooth rather than a small section like I think it should have. I'm not sure if it's my pinion depth is set wrong and causing it. I have 22 in/lbs of drag on pinion. I used the same shim that I removed from the old pinion since they were both Ford Racing. It was a .025" shim. I have between .008" and .010" of backlash on the ring gear. Anybody have any ideas? I have attached some pictures.

20160503_185107.jpg


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That's a good question, I'm getting ready to put my rear together with all new pieces too.

That is a wide pattern, I would think pinion depth would be the problem.

Let me get our resident genius to chime in, if he doesn't know, he'll know where to get the answer.

@jrichker , help.
 
After much research I found out there are 2 machining processes used in machining ring and pinion gears. The 2 processes are "face milled" and "face hobbed". All new Ford 8.8-inch original equipment and Ford Racing gears are face hobbed. This is where I was messing up. Face hobbed gear sets have a different set up procedure when making adjustments. All the searches I found on Google showed only the adjustments for face milled gears. Check out this link. It is extremely informative.
http://diyford.com/ford-axle-ring-pinion-assembly-guide/
 
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After much research I found out there are 2 machining processes used in machining ring and pinion gears. The 2 processes are "face milled" and "face hobbed". All new Ford 8.8-inch original equipment and Ford Racing gears are face hobbed. This is where I was messing up. Face hobbed gear sets have a different set up procedure when making adjustments. All the searches I found on Google showed only the adjustments for face milled gears. Check out this link. It is extremely informative.
http://diyford.com/ford-axle-ring-pinion-assembly-guide/
I've learned a new thing! Thanks brother.