Hello Everyone!
I have a 1994 Mustang GT with Automatic Transmission. This is my dream car and I love it. However, I love what I want to do with it more! That said, While I am not a paid mechanic, I have built a chopper, maintained and upgraded a Jeep and now moved to my Mustang. I decided I wanted to upgrade the rear gears from 2.73 to 3.73 earlier this year. For my birthday, I received a set of Ford Racing Gears. Following the instructions at CJPonyParts, I conducted the upgrade. In an effort to make my life easy, I had installed a Yukon Gears Crush Sleeve Eliminator... numerous times... to get the preload right. When it was 22 inch pounds, I installed the carrier and set backlash at .009 - then put it all back together, included a little of 2 quarts of Royal Purple (expensive stuff, but if you are doing it, so it right, right?).
I drove it for about 30 miles to get the initial break-in started. Toward the end of that stretch, I started to feel a weird deceleration clunk. I drove the car another 250 miles, figuring the clunk was a bad u-joint or loose control arm. this was a total of about 4 days. It got progressively worse, so I pulled it into the garage and verified that the pinion was loose and the clunk as the pinion settling down on deceleration, only to go back up on acceleration. So... I got to take it all apart again....
I finished the second rebuild today. I spent 2 days trying to get the crush sleeve eliminator to allow for any bearing preload. I couldn't get any preload at all - even with ZERO shims. I could get the pinion nut tight, with no movement, but could not get any preload. I thought the bearings may have been ruined by the modest about of driving I had done, so I replaced them and this time, installed with a crush sleeve instead of the eliminator. Crushing that thing is not easy, but I was able to get it to preload the bearings to 26 inch pounds. As the pinion preload was a little more than the last time, my backlash was a little out of line, so I got the fun of redoing the shims in the carrier. This time, backlash measurement was an average of .0875 (measured in four places). I recognize this is a little tight, but figured it would loosen up a little over time... so I put it all back together and took it for a drive...
I have put about 10 miles on it, just around town... and the deceleration clunk is there. There is not a sound with it (yet), which is how it was originally before I drove the additional miles.
I had my measurements checked by a friend to confirm the pinion preload and carrier backlash, as it thought I had done that wrong... I'm a little lost of how this pinion could be loose, after all the parts being installed to spec.
Does anyone have any idea how this could happen, or what I need to look for that would cause this problem? Any input is appreciated.
Thanks,
RufusT
I have a 1994 Mustang GT with Automatic Transmission. This is my dream car and I love it. However, I love what I want to do with it more! That said, While I am not a paid mechanic, I have built a chopper, maintained and upgraded a Jeep and now moved to my Mustang. I decided I wanted to upgrade the rear gears from 2.73 to 3.73 earlier this year. For my birthday, I received a set of Ford Racing Gears. Following the instructions at CJPonyParts, I conducted the upgrade. In an effort to make my life easy, I had installed a Yukon Gears Crush Sleeve Eliminator... numerous times... to get the preload right. When it was 22 inch pounds, I installed the carrier and set backlash at .009 - then put it all back together, included a little of 2 quarts of Royal Purple (expensive stuff, but if you are doing it, so it right, right?).
I drove it for about 30 miles to get the initial break-in started. Toward the end of that stretch, I started to feel a weird deceleration clunk. I drove the car another 250 miles, figuring the clunk was a bad u-joint or loose control arm. this was a total of about 4 days. It got progressively worse, so I pulled it into the garage and verified that the pinion was loose and the clunk as the pinion settling down on deceleration, only to go back up on acceleration. So... I got to take it all apart again....
I finished the second rebuild today. I spent 2 days trying to get the crush sleeve eliminator to allow for any bearing preload. I couldn't get any preload at all - even with ZERO shims. I could get the pinion nut tight, with no movement, but could not get any preload. I thought the bearings may have been ruined by the modest about of driving I had done, so I replaced them and this time, installed with a crush sleeve instead of the eliminator. Crushing that thing is not easy, but I was able to get it to preload the bearings to 26 inch pounds. As the pinion preload was a little more than the last time, my backlash was a little out of line, so I got the fun of redoing the shims in the carrier. This time, backlash measurement was an average of .0875 (measured in four places). I recognize this is a little tight, but figured it would loosen up a little over time... so I put it all back together and took it for a drive...
I have put about 10 miles on it, just around town... and the deceleration clunk is there. There is not a sound with it (yet), which is how it was originally before I drove the additional miles.
I had my measurements checked by a friend to confirm the pinion preload and carrier backlash, as it thought I had done that wrong... I'm a little lost of how this pinion could be loose, after all the parts being installed to spec.
Does anyone have any idea how this could happen, or what I need to look for that would cause this problem? Any input is appreciated.
Thanks,
RufusT