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Yesterday I drove almost 3 hours to a shop to get my gears installed, and no local shops could give me a decent quote (all the local shops wanted between $1000 and $2000 for labor to install new gears..). The shop I went to has a good reputation and the guy has a lot of experience installing gears in the Ford 8.8 rear ends. Let's get to the point:
The guy let me be in the shop and observe his work, and except for a problem removing the old 3.27 pinion everything went smooth. He measured the pinion depth using a special FRPP tool and shimmed appropriately. After all was said and done the backlash was 0.007, he told me it was so close to spec (0.008-0.014) that it would be fine, and that the gears will break in giving the end result of a backlash that is within spec. The guy reused the old crush sleeve, but all other hardware was new. He said it does not matter as long as the preload set on the pinion nut is correct.
On my way home I got on the interstate and felt a vibration throughout the car during deceleration at speeds above 65mph. This only occurs above 65mph, and is worst at part-throttle deceleration. If I let all the way off the gas it still vibrates, but not as bad. I called the guy and we went back to the shop and looked at it. He had put the driveshaft back in the same spot where he marked it, I saw that myself. We ended up walking the driveshaft (rotating it 90 degrees at a time) and found a spot where the vibrations were not as bad. As it is now the vibrations occur at deceleration above 70mph, and is worse under part-throttle deceleration. There is no noticeable vibration during acceleration below 110mph, I did not try to go any faster than that yesterday. The vibrations disappear as soon as I get to speeds below 70mph or start accelerating again. There is absolutely no gear whine, and the gears meshed perfectly in the middle from what we saw using the marking compound.
The mechanic gave me a 3 year warranty on the labor and is willing to do whatever it takes to make his customer satisfied, it just sucks that the shop is almost 3 hours away, which means 1.5 tanks of gas to make the roundtrip. He thinks the driveshaft and pinion flange along with the new pinion is causing a slight imbalance, is this correct or is there something wrong with the gear install?
I love the 4.10 gears so far. I have put 250 highway miles on them, but have not gotten on them yet. As mentioned everything is as smooth as can be below 70mph now, no vibrations at all. There is absolutely no whine from the gears at any speed, only some vibrations at deceleration above 70mph.
The guy let me be in the shop and observe his work, and except for a problem removing the old 3.27 pinion everything went smooth. He measured the pinion depth using a special FRPP tool and shimmed appropriately. After all was said and done the backlash was 0.007, he told me it was so close to spec (0.008-0.014) that it would be fine, and that the gears will break in giving the end result of a backlash that is within spec. The guy reused the old crush sleeve, but all other hardware was new. He said it does not matter as long as the preload set on the pinion nut is correct.
On my way home I got on the interstate and felt a vibration throughout the car during deceleration at speeds above 65mph. This only occurs above 65mph, and is worst at part-throttle deceleration. If I let all the way off the gas it still vibrates, but not as bad. I called the guy and we went back to the shop and looked at it. He had put the driveshaft back in the same spot where he marked it, I saw that myself. We ended up walking the driveshaft (rotating it 90 degrees at a time) and found a spot where the vibrations were not as bad. As it is now the vibrations occur at deceleration above 70mph, and is worse under part-throttle deceleration. There is no noticeable vibration during acceleration below 110mph, I did not try to go any faster than that yesterday. The vibrations disappear as soon as I get to speeds below 70mph or start accelerating again. There is absolutely no gear whine, and the gears meshed perfectly in the middle from what we saw using the marking compound.
The mechanic gave me a 3 year warranty on the labor and is willing to do whatever it takes to make his customer satisfied, it just sucks that the shop is almost 3 hours away, which means 1.5 tanks of gas to make the roundtrip. He thinks the driveshaft and pinion flange along with the new pinion is causing a slight imbalance, is this correct or is there something wrong with the gear install?
I love the 4.10 gears so far. I have put 250 highway miles on them, but have not gotten on them yet. As mentioned everything is as smooth as can be below 70mph now, no vibrations at all. There is absolutely no whine from the gears at any speed, only some vibrations at deceleration above 70mph.
