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  1. #1

    Default Any ideas on what this high-pitched whine is?

    After putting my car back together, I have a high-pitched whine whenever I take my foot off the gas. It is even more pronounced on the highway. I don't recall having this noice before, but I will paraphrase the upgrades/likely culprits:

    Engine/transmission/clutch all unchanged since I stored it.

    -I added a completely rebuilt with new components 8.8 rear end, so obviously couldn't mark and return the drive shaft to it's previous holes.
    I also don't currently have the "dog bone" installed.
    -Tires are the same ones that have been on since I put it in storage 20 years ago.
    -I added all new bearings in each wheel and new brakes

    Here's a link to video of the sound. You can see it comes in the moment, I take my foot off the gas: https://youtu.be/C_rDFZRTA_o

    Appreciate any input!

  2. #2
    FEP Power Member Broncojunkie's Avatar
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    Usually that is an issue with the pinion bearing. Who rebuilt the 8.8? If it was done locally, maybe they could check it?
    79 Pace Car - 331, t5
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  3. #3
    Moderator wraithracing's Avatar
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    Sounds like your pinion bearing preload may not be correct. As mentioned above if possible have the person who rebuilt the 8.8 take a look at it. Good Luck!
    ​Trey

    "I Don't build it hoping for your approval! I built it because it meets mine!"

    "I've spent most of my money on Mustangs, racing, and women... the rest I just wasted."

    Mustangs Past: Too many to remember!
    Current Mustangs:
    1969 Mach 1
    1979 Pace Car now 5.0/5 speed
    1982 GT Stalled RestoModification
    1984 SVO Still Waiting Restoration
    1986 GT Under going Wide Body Conversion Currently

    Current Capris:
    1981 Capri Roller
    1981 Capri Black Magic Roller Basket Case
    1982 Capri RS 5.0/4spd T-top Full Restoration Stalled in TX
    1984 Capri RS T-top Roller
    1983-84 Gloy Racing Trans Am/IMSA Body Parts

  4. #4

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    Quote Originally Posted by Broncojunkie View Post
    Usually that is an issue with the pinion bearing. Who rebuilt the 8.8? If it was done locally, maybe they could check it?
    Hmm, it was done by a transmission shop more than a year ago, but these are likely the first 30 miles since install. I feel like I always grief when that amount of time passes despite not using the parts.

  5. #5

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    And thanks for the replies!

  6. #6

    Default

    Quote Originally Posted by wraithracing View Post
    Sounds like your pinion bearing preload may not be correct. As mentioned above if possible have the person who rebuilt the 8.8 take a look at it. Good Luck!
    Do you know if that is a big deal to adjust after it's already been sealed up?

    I know they're going to push back since they did the work over a year ago despite it only just being driven.

  7. #7
    Moderator wraithracing's Avatar
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    It depends on what is going on. If the pinion nut is essentially not tight, then yes that can be tightened without having to remove anything other than the driveshaft. That assumes that your pinion depth is correct in regards to shims and/or crush sleeve.

    The first thing to do is get under the car and see if you can move the pinion with your hand. Pinion should rotate and have just a small amount of backlash, but should not move up and down or in/out of the rear housing. If it does that needs to be addressed ASAP. If the pinion is tight with no signs of excess movement, then there is a chance the pinion depth or backlash is not set correctly. That could be causing whine on the coast side of the gears. The other issue could also be a possible bad bearing in the rear end, but if properly rebuilt that is unlikely.

    I personally would call the shop and inform them of the situation. Hopefully they can take a look and see that the rear end has little to no mileage on it and will address any issues that might be at fault with their installation. Good luck!
    ​Trey

    "I Don't build it hoping for your approval! I built it because it meets mine!"

    "I've spent most of my money on Mustangs, racing, and women... the rest I just wasted."

    Mustangs Past: Too many to remember!
    Current Mustangs:
    1969 Mach 1
    1979 Pace Car now 5.0/5 speed
    1982 GT Stalled RestoModification
    1984 SVO Still Waiting Restoration
    1986 GT Under going Wide Body Conversion Currently

    Current Capris:
    1981 Capri Roller
    1981 Capri Black Magic Roller Basket Case
    1982 Capri RS 5.0/4spd T-top Full Restoration Stalled in TX
    1984 Capri RS T-top Roller
    1983-84 Gloy Racing Trans Am/IMSA Body Parts

  8. #8

    Default

    Quote Originally Posted by wraithracing View Post
    It depends on what is going on. If the pinion nut is essentially not tight, then yes that can be tightened without having to remove anything other than the driveshaft. That assumes that your pinion depth is correct in regards to shims and/or crush sleeve.

    The first thing to do is get under the car and see if you can move the pinion with your hand. Pinion should rotate and have just a small amount of backlash, but should not move up and down or in/out of the rear housing. If it does that needs to be addressed ASAP. If the pinion is tight with no signs of excess movement, then there is a chance the pinion depth or backlash is not set correctly. That could be causing whine on the coast side of the gears. The other issue could also be a possible bad bearing in the rear end, but if properly rebuilt that is unlikely.

    I personally would call the shop and inform them of the situation. Hopefully they can take a look and see that the rear end has little to no mileage on it and will address any issues that might be at fault with their installation. Good luck!
    Hey, thanks again for the advice. I've got an appointment Monday to have the transmission shop try to correct.

    One thing that just occurred to me as I was making another post on attaching the rear end weight (dog bone) is could that be the problem? I kept it off after reading other posts where people thought it often wasn't necessary.

  9. #9
    Moderator wraithracing's Avatar
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    I doubt the dog bone weight being removed would cause your issue. The dogbone was installed for NVH reasons by Ford. If that concerns you or you want to address those issues, then reinstall it. Most performance oriented individuals would prefer to remove it and save the weight. Good Luck!
    ​Trey

    "I Don't build it hoping for your approval! I built it because it meets mine!"

    "I've spent most of my money on Mustangs, racing, and women... the rest I just wasted."

    Mustangs Past: Too many to remember!
    Current Mustangs:
    1969 Mach 1
    1979 Pace Car now 5.0/5 speed
    1982 GT Stalled RestoModification
    1984 SVO Still Waiting Restoration
    1986 GT Under going Wide Body Conversion Currently

    Current Capris:
    1981 Capri Roller
    1981 Capri Black Magic Roller Basket Case
    1982 Capri RS 5.0/4spd T-top Full Restoration Stalled in TX
    1984 Capri RS T-top Roller
    1983-84 Gloy Racing Trans Am/IMSA Body Parts

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