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drmhagarty
Samba Member
Joined: September 28, 2016
Posts: 9
Location: Coralville Iowa
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 Posted: Mon Aug 13, 2018 8:12 pm Post subject: Unusual sound from final drive |
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Hello, first post, been browsing since I bought my bus about 1.5 years ago. I have a 73 adventurewagen with original 1700 dual solex carbs and automatic transmission. Engine and trans were rebuilt right after I bought it. Been running great and shifting great for last 3500 miles. However I have a new noise. It is a whining sound that corresponds to rpm, rpm increase equals more whining. It happens in park, neutral, and drive. At first I thought it was something caught in the fan. Blew that out with compressed air nothing came out. Checked for bad alt bearing by removing the belt, still no change in sound. I traced the sound with a long flat screwdriver held up to my ear to the transaxle area. Sounds like a dry noise, not wet or muffled. ATF looks good. No leaks at all. I don’t see anything binding or rubbing on the torque converter. Haven’t checked the gear oil level yet, need to get a new tool to get the filler cap off. It runs and drives and shifts great, just the whining sound has me baffled. Anybody have advice before dig any deeper? I’ll try and link the video of the noise.
https://youtu.be/F25ElzfZt3Q |
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Wildthings
Samba Member
Joined: March 13, 2005
Posts: 50352
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| Posted: Mon Aug 13, 2018 10:11 pm Post subject: Re: Unusual sound from final drive |
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| Don't have any really good idea of what it might be. Have you checked to see if your starter drive is pulling back in and not staying engaged with the ring gear? |
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drmhagarty
Samba Member
Joined: September 28, 2016
Posts: 9
Location: Coralville Iowa
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| Posted: Tue Aug 14, 2018 7:21 am Post subject: Re: Unusual sound from final drive |
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| Wildthings wrote: |
| Don't have any really good idea of what it might be. Have you checked to see if your starter drive is pulling back in and not staying engaged with the ring gear? |
That had crossed my mind, I was trying to think of a way to pull the starter and then start the bus to rule that out. Being an Automatic it kind of rules out bump starting. I suppose I could pull it and look for excess wear and bench test it. I assume though if it was running with the starter still engaged it would burn it up quick, but then again maybe not, i have driven with the noise in town only for about 10 miles. The sound does resemble a gear motor overspinning. |
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aeromech
Samba Member
Joined: January 24, 2006
Posts: 16971
Location: San Diego, California
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| Posted: Tue Aug 14, 2018 9:59 am Post subject: Re: Unusual sound from final drive |
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Contact this guy, wasted youth
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sjbartnik
Samba Member
Joined: September 01, 2011
Posts: 5998
Location: Brooklyn
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| Posted: Tue Aug 14, 2018 10:44 am Post subject: Re: Unusual sound from final drive |
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Does it correspond to engine rpm or wheel rpm?
I'm assuming engine rpm since it occurs even when the vehicle is stationary. That would not implicate final drive but would implicate something that is rotating with engine running.
ATF pump inside the trans maybe?
A video would be dope.
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drmhagarty
Samba Member
Joined: September 28, 2016
Posts: 9
Location: Coralville Iowa
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| Posted: Tue Aug 14, 2018 3:21 pm Post subject: Re: Unusual sound from final drive |
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| sjbartnik wrote: |
Does it correspond to engine rpm or wheel rpm?
I'm assuming engine rpm since it occurs even when the vehicle is stationary. That would not implicate final drive but would implicate something that is rotating with engine running.
ATF pump inside the trans maybe?
A video would be dope. |
The sound is linked to engine RPM not wheel RPM. I linked a youtube video of the sound at the bottom of the original post. I thought possibly ATF pump, but its shifting fine. I assume if the pump is bad the shifting would be erratic. |
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Spike0180
Samba Member
Joined: June 06, 2015
Posts: 2269
Location: Detroit, Michigan
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| Posted: Thu Aug 16, 2018 5:19 am Post subject: Re: Unusual sound from final drive |
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| drmhagarty wrote: |
| sjbartnik wrote: |
Does it correspond to engine rpm or wheel rpm?
I'm assuming engine rpm since it occurs even when the vehicle is stationary. That would not implicate final drive but would implicate something that is rotating with engine running.
ATF pump inside the trans maybe?
A video would be dope. |
The sound is linked to engine RPM not wheel RPM. I linked a youtube video of the sound at the bottom of the original post. I thought possibly ATF pump, but its shifting fine. I assume if the pump is bad the shifting would be erratic. |
I don't think I would assume that since it is shifting fine that the pump isn't about to die and hence making noice. Being hydraulic it could leak (and wine) for some time while still being able to maintain pressure in the system.
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sjbartnik
Samba Member
Joined: September 01, 2011
Posts: 5998
Location: Brooklyn
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| Posted: Thu Aug 16, 2018 10:05 am Post subject: Re: Unusual sound from final drive |
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After hearing it I think I'm gonna stand by my hunch of ATF pump. I don't know the layout of the auto trans so I don't know where in the case the ATF pump lives.
The sound does remind me of other dying hydraulic pumps I've heard before (i.e. power steering pumps).
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2000 Kawasaki W650 |
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drmhagarty
Samba Member
Joined: September 28, 2016
Posts: 9
Location: Coralville Iowa
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| Posted: Thu Aug 16, 2018 9:58 pm Post subject: Re: Unusual sound from final drive |
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| sjbartnik wrote: |
After hearing it I think I'm gonna stand by my hunch of ATF pump. I don't know the layout of the auto trans so I don't know where in the case the ATF pump lives.
The sound does remind me of other dying hydraulic pumps I've heard before (i.e. power steering pumps). |
My first thought was that it sounded like a power steering/hydraulic pump starting to fail, which I guess isn’t much different from an ATF pump. The pump is in the far front of the case which seems to be the origin of the noise. My plan is to look for another 003 trans to rebuild and swap or use for parts and to rebuild the one I have. Now if I could find another 003 trans somewhere. |
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Wildthings
Samba Member
Joined: March 13, 2005
Posts: 50352
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| Posted: Thu Aug 16, 2018 10:33 pm Post subject: Re: Unusual sound from final drive |
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| drmhagarty wrote: |
| sjbartnik wrote: |
After hearing it I think I'm gonna stand by my hunch of ATF pump. I don't know the layout of the auto trans so I don't know where in the case the ATF pump lives.
The sound does remind me of other dying hydraulic pumps I've heard before (i.e. power steering pumps). |
My first thought was that it sounded like a power steering/hydraulic pump starting to fail, which I guess isn’t much different from an ATF pump. The pump is in the far front of the case which seems to be the origin of the noise. My plan is to look for another 003 trans to rebuild and swap or use for parts and to rebuild the one I have. Now if I could find another 003 trans somewhere. |
A stuck spool/valve will load the pump and cause a screaming sound. |
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