I have a question for you mustang or ford veterans,but first some history. I purchased a 95GT about 4 months ago and started a wish list. Two weekends ago I decided to change the rear gears. So I ordered the gears and shim kit from awell known supplier of Mustang parts and wanted Ford Racing parts as I thoughtthey were standard ford parts. Firstproblem was the shim kit. Ford uses fullthickness shims and I received an assortment of thin shims. I noticed that the carrier bearing caps donot cover the shims. This is notgood. So I went to a ford dealer to seeif I could get the original ford shims. Theydo not stock them and they sent me to an independent shop where they get themfrom that does install gears and said they had them. So I called and they said yes they havethem. So I ride down with my fordworkshop manual to get the shims I needed. When I got there the owner hands me a shim kit like I have. I said no I want the ford one piece shims;the ones with the paint strips and full thickness. He kind of laughed at me and said no one hasthose. Ford gets $16.00 a piece and aset is $400.00. Then he says my shims are not like the ones hehad. His were different. One of the thick shims for each side has ashoulder on the inside diameter so when you sandwich the thin shims with theother thick shim the shoulder keeps all the shims in place and the bearing cap coversthe inside shim with the shoulder to secure all of the shims. The carrier shim kit and the pinion shim kitwas $45.00 so I purchased them.
Now I need to preference this with I have never donea ford rear but many corvette rears. Theirshims are much thicker and are covered by the cap. I do not want to start a Ford Chevy war butjust telling you my experience. I doknow what I am doing. This will becomeclear as I continue.
I start with the pinion shim that came off theoriginal pinion (.029) and preload the pinion shim bearings with an in-lbtorque wrench by the book. Put in thecarrier and set the preload to zero with a backlash of between 8-12 thousands,painted the ring gear about 8 teeth and turn the pinion while putting a drag onthe ring gear to get a pattern. Patternis on the heel for the driver side and on the toe on the coast side. Book saysto increase the pinion shim. This willmove the driver side toward the toe and the coast side to the heel. The idea with the pinion shim is to get thepatterns opposite each other and with a light load they both should be on thetoe side of center.
To make this short I went to .032 got a little bitbetter, went to .0345 got a little better, went to .036 no different. Went to .038 looked like it got worse. Went to .044 got worse went to.052 and waseven worse. Next day started over and went back to the .029. Put a little preload on the carrier bearingsand was more exact on the backlash; kept it between 11-13 thousands. Went to .032 again got better went to .0345and this is where it was the best but not really correct. Drive still on the heel and coast on the toeside of center. Said I cannot keep doingthis again and left it with the .0345 and put everything back together. Car runs well and no noise.
Here is the problem – besides not getting the idealpattern the pattern on each tooth was different. I went all around the ring gear in differentplaces. The pattern was not consistent. I never had this problem with the corvettegears. This leads me to believe the gears were the problem. The person who sold me the shim kit asked mewhere I got the gears and I said ford racing. He told me that the ford racing parts are NOT the same as standard ford OEMparts. The gears that they will not usein production cars are packaged and sold as ford racing parts. I do not know if this is true or notbut!!! More info – when I bought the corvettegears they were direct from a chevy dealer at the parts counter. ( I had an inwith chevy at the time). This was in the1970’s and I paid about $160.00 for the gears at a discount. It is hard for me to believe that I can getthe same quality now for $155.00 from ford racing as this is what I paid forthe ford gears. The proof is in thepattern!
The question is “are ford racing parts seconds orare ford parts just not machined as precise as I am used to”. If I do another gear change I am going to goto a dealer and buy standard OEM gears. I will probably have to pay I’m guessing 400-500 dollars. Also the backlash on the corvette gears was.005-.008 and I have a 1968 Pontiac shop manual and the backlash is .005-009. Why is ford .008-.015 with .012-.015 preferred? Is it because they gears are not manufacturedto close tolerances?
So what’s the skinny with ford racing parts??
Thanks
Now I need to preference this with I have never donea ford rear but many corvette rears. Theirshims are much thicker and are covered by the cap. I do not want to start a Ford Chevy war butjust telling you my experience. I doknow what I am doing. This will becomeclear as I continue.
I start with the pinion shim that came off theoriginal pinion (.029) and preload the pinion shim bearings with an in-lbtorque wrench by the book. Put in thecarrier and set the preload to zero with a backlash of between 8-12 thousands,painted the ring gear about 8 teeth and turn the pinion while putting a drag onthe ring gear to get a pattern. Patternis on the heel for the driver side and on the toe on the coast side. Book saysto increase the pinion shim. This willmove the driver side toward the toe and the coast side to the heel. The idea with the pinion shim is to get thepatterns opposite each other and with a light load they both should be on thetoe side of center.
To make this short I went to .032 got a little bitbetter, went to .0345 got a little better, went to .036 no different. Went to .038 looked like it got worse. Went to .044 got worse went to.052 and waseven worse. Next day started over and went back to the .029. Put a little preload on the carrier bearingsand was more exact on the backlash; kept it between 11-13 thousands. Went to .032 again got better went to .0345and this is where it was the best but not really correct. Drive still on the heel and coast on the toeside of center. Said I cannot keep doingthis again and left it with the .0345 and put everything back together. Car runs well and no noise.
Here is the problem – besides not getting the idealpattern the pattern on each tooth was different. I went all around the ring gear in differentplaces. The pattern was not consistent. I never had this problem with the corvettegears. This leads me to believe the gears were the problem. The person who sold me the shim kit asked mewhere I got the gears and I said ford racing. He told me that the ford racing parts are NOT the same as standard ford OEMparts. The gears that they will not usein production cars are packaged and sold as ford racing parts. I do not know if this is true or notbut!!! More info – when I bought the corvettegears they were direct from a chevy dealer at the parts counter. ( I had an inwith chevy at the time). This was in the1970’s and I paid about $160.00 for the gears at a discount. It is hard for me to believe that I can getthe same quality now for $155.00 from ford racing as this is what I paid forthe ford gears. The proof is in thepattern!
The question is “are ford racing parts seconds orare ford parts just not machined as precise as I am used to”. If I do another gear change I am going to goto a dealer and buy standard OEM gears. I will probably have to pay I’m guessing 400-500 dollars. Also the backlash on the corvette gears was.005-.008 and I have a 1968 Pontiac shop manual and the backlash is .005-009. Why is ford .008-.015 with .012-.015 preferred? Is it because they gears are not manufacturedto close tolerances?
So what’s the skinny with ford racing parts??
Thanks
