Ford 9 inch 28 spline ring and pinion -
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Unread 11-18-2006, 09:14 PM   #1
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Ford 9 inch 28 spline ring and pinion

I have a problem in locating a Ford 9 inch 28 spline gearset. Here is the problem, 1970 I built a FED. using Ford OEM rear and a 1963 chrysler 727 tranny. A coupler was made using a Ford yoke and a governor support, machining them so a steel sleeve went over each and welded. last year I finally busted the rear and case. Got all new parts and a motive 4.56 ring and pinion. That's when my problems started. Never checked the pinion splines and made 10 runs and wiped out the rear pump. Took me 6 months and even made a new coupler. When that dial indicated .015 runout when on the pinion, I thought that the new gears was the problem. Sure enough it was. So the company took the gears back. I found out all new splines are straight cut, have a tolerance on the major diameter of spline of 1.203 to 1.208 and are cut .003 deeper on the root giving a spline backlash of .004 inches. The OEM ford is 1.210 inches, a helix cut spline, wider teeth and involute cut and no backlash. I thought Richmond was American made. Yes, but they machine the same as overseas market and in fact Stewart Hamilton of Richmond said all, gears made today are machined this way. The problem is when the coupler goes on the splines it slides on where the OEM splines it's a palm press fit then the nut is tightened and it is then an interference fit. Also the coupler will not even shake off, but the new splines the coupler starts sliding off when at a 45 degree angle. So I am SOL unless I can find a real OEM gearset for the slingshot. I would settle for a used one if it was 4.11 or higher up to a 4.56 and pushing it a 4.86. Would any of you know of any places that might have such a gear set?
Please get back to me asap as I am still searching and some NOS dealers still can't find what I need. A lot of their gears they have , believe it or not, have 29 splines and are Ford OEM parts like Ford part number c7tz 4209-c. I listened as the man counted the splines, twice, over the phone that he was counting right. Most are trucks and the parts are made for military that are still new but could be in india at an army wharehouse. Please if you can help me let me know.

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Unread 11-18-2006, 10:12 PM   #2
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