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#1 |
Registered User
![]() Join Date: Apr 2014
Location: detroit mi
Posts: 208
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whining noise when accelerating - from where?
I have finally got my truck drivable after a year and a half of fixing a ton of stuff. Now im chasing down a whining noise when accelerating from 20 to 60 mph. The noise seems to get louder the faster I go. It goes away when I let off the gas. I havent gone over 60 yet, still in shakedown mode.
Background info is the truck is a 71 LWB 2wd 350/350 with 3.73 open diff. It has had a serpentine setup from a 90 chevy with new alternator, fan, fan clutch and waterpump. The drivetrain has new flexplate, rebuilt th350 with new converter, re-balanced drive shaft with new carrier bearing and new u-joints, the rear axle fluid changed. Rear gears were a bit rusty from sitting for so long, looks like a few teeth are lightly pitted but no chips or bigger damage. any ideas? |
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#2 |
20' Daredevil (Ret)
![]() Join Date: May 2003
Location: Jefferson State
Posts: 13,628
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Re: whining noise when accelerating - from where?
Just a guess.... being speed-related (20 to 60 mph) and only when accelerating, it may be the differential.
__________________
- Mike - 1972 K20 LWB 350/350/205 RIP El Jay |
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#3 |
Registered User
Join Date: May 2017
Location: Parker, CO
Posts: 130
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Re: whining noise when accelerating - from where?
More than a few years ago I had a similar issue on an inboard boat engine. Turned out to be a vacuum leak between the intake and head. Tightened down on the bolts and it got better but had to replace the intake gasket to make it go away.
I was only 14 and learned how to properly install an intake from that experience... |
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#4 |
Registered User
Join Date: Aug 2016
Location: Lake Forest, CA
Posts: 2,177
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Re: whining noise when accelerating - from where?
I 2nd that.
__________________
"Work hard, use your vacation days." 1970 C15 GMC Long Bed 1986 C20 Scottsdale 1983 K2500 Sierra Classic Suburban 6.2 Instagram: C10sofOC |
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#5 |
Registered User
Join Date: Oct 2005
Location: Overland Park, Ks.
Posts: 5,216
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Re: whining noise when accelerating - from where?
My vote is for the rear end. Check for any looseness in the pinion brgs. If that's OK pull the cover back off & check for any side to side motion in the carrier. If that's OK check the tooth contact pattern in the ring & pinion.
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#6 |
Senior Member
![]() Join Date: Jan 2001
Location: Orem, Utah
Posts: 7,908
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Re: whining noise when accelerating - from where?
My first thought was the pinion bearing. Most likely culprit, in my opinion.
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#7 |
Registered User
Join Date: Feb 2017
Location: reno nv
Posts: 64
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Re: whining noise when accelerating - from where?
Its the Rear Diff.
mine does the same thing, whines louder as I go faster, take foot off gas, sound goes away....my 72 C20 with 4.11 rear gear, piņion is worn. trucked lugged a heavy 10 ft Alaskan camper in back its whole life, just had the motor worked on.. new cam and lifters installed this week and motor sounds smooth. still have the rear diff noise. won't hurt anything if not being used to work hard towing or hauling (camper is removed now)...I'll let mine whine for another year until I can afford to have a 700r tranny installed and will have the worn 4.11 pulled and install a 3.73 at that time. |
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#8 |
Registered User
Join Date: Oct 2016
Location: Dallas Texas
Posts: 3,090
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Re: whining noise when accelerating - from where?
Sounds like gear whine.
-klb
__________________
67 C10 fleet fuel injected '70 402, 700r4, 3.73 posi 07 335 sport turbo 6sp 94 Trans Am GT LT1 6sp posi -- sold after 22yrs 99 540 sport V8 6sp -- sold 73 240z L24 4sp -- given to friend 68 C10 step 350/350 3.73 open -- sold |
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#9 |
Registered User
Join Date: Apr 2012
Location: Ocala,Fl
Posts: 733
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Re: whining noise when accelerating - from where?
Did you replace the pinion seal when you were into the differential?
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#10 | |
Registered User
![]() Join Date: Apr 2014
Location: detroit mi
Posts: 208
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Re: whining noise when accelerating - from where?
Quote:
Its quite loud around 45, guess ill get on the radio install. |
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#11 |
Go Pack Go!
Join Date: Nov 2005
Location: Green Bay
Posts: 2,669
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Re: whining noise when accelerating - from where?
I had the same thing. In my case it was the wife bearing. Bought her some chocolates and flowers and the whining went away for a while,
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