Transmission Squealing - The 1947 - Present Chevrolet & GMC Truck Message Board Network

crawdad · 10-26-2007, 06:40 PM

Took the 85 out on another test run today to check out the power steering. When I got home and had it idling, I heard, what I thought was a fan belt squealing. I opened the hood and it was quiet under the hood. I stuck my head under the truck and it sounded like it was coming from the transmission, more on the passenger side than the drivers side. The tranny pulls real good and seems to work well in all gears (although the shift points are REAL close together). Sound does not go away as I shift it through the gears, nor does it go away when I rev it up, although it does seem to get quieter. When I shut the engine off, the noise seemed to just bleed off, almost like a vacuum leak loosing air or something. I really don't think anything is wrong with the tranny itself, but is there anything on the tranny that could cause a squealing like this?

Would appreciate your ideas/suggestions. Thanks.

**old Rusty C10** · 10-26-2007, 06:45 PM

check the modulator valve on it and the vacuum that attaches to it hopefully its like a pinhole or something there

chev74 · 10-26-2007, 06:55 PM

sounds like something vacuum to me. possibly a cracked line that is sucking air and making it whistle.
always a good idea to just replace any vacuum lines that look leery of cracking. cheap way to solve easy problems before spending a lot of money on something unnecessary- plus is aids in the 'process of elimination factor'

78chev · 10-26-2007, 11:31 PM

Get a big ol' cigar and do a smoke test.

crawdad · 10-29-2007, 05:23 PM

I climbed back under the truck today to see if I could see anything out of the ordinary. I really need to get it up on a car rack to do any good however. The vacuum line to the modulator seems to be ok and is hooked up properly. I tried to pinpoint the location of the squeal a little more closely, and as far as I could tell (I'm about deaf

, it seems to be coming more from the front of the tranny rather than the back, almost right up there next to the torque converter. When I shut if off, however, I'm still hearing that sound that sounds much like a vacuum bleed-off, for lack of a better term. Like I said earlier, the tranny pulls and shifts out very good, although the shift points are a little quick, so I hope it ain't getting ready to bite the dust on me. Is there anything "inside" of the transmission that could be making a squeal like that?

**old Rusty C10** · 10-29-2007, 05:32 PM

could there be a small hole in the metal part of the vacuum line?

10-26-2007, 06:40 PM	#1
crawdad Senior Member Join Date: Sep 2004 Location: Georgia Posts: 614	Transmission Squealing Took the 85 out on another test run today to check out the power steering. When I got home and had it idling, I heard, what I thought was a fan belt squealing. I opened the hood and it was quiet under the hood. I stuck my head under the truck and it sounded like it was coming from the transmission, more on the passenger side than the drivers side. The tranny pulls real good and seems to work well in all gears (although the shift points are REAL close together). Sound does not go away as I shift it through the gears, nor does it go away when I rev it up, although it does seem to get quieter. When I shut the engine off, the noise seemed to just bleed off, almost like a vacuum leak loosing air or something. I really don't think anything is wrong with the tranny itself, but is there anything on the tranny that could cause a squealing like this? Would appreciate your ideas/suggestions. Thanks. __________________ 2012 Silverado LT 1500, 5.3, 6 speed auto '86 SWB C-10 Silverado

10-26-2007, 06:45 PM	#2
old Rusty C10 Robert Olson Transport Join Date: Oct 2002 Location: recent transplant to NC USA Posts: 20,310	Re: Transmission Squealing check the modulator valve on it and the vacuum that attaches to it hopefully its like a pinhole or something there __________________ Bob 1951 International running on a squarebody chassis "If a man's worth is judged by the people he associates himself with, then i am the richest man in the world knowing some of the fine people of this board" http://67-72chevytrucks.com/vboard/a...t.php?f=25&a=9 (you can review the site rules here!) PM Me for your vehicle/parts hauling needs in the North East US or see my Facebook page Robert Olson Transport Live each day to the fullest.. you never know when fate is going to pull the rug out from under you... I hate cancer!!

10-26-2007, 06:55 PM	#3
chev74 Addicted to Chevy Join Date: Dec 2004 Location: Tyler, Tx Posts: 857	Re: Transmission Squealing sounds like something vacuum to me. possibly a cracked line that is sucking air and making it whistle. always a good idea to just replace any vacuum lines that look leery of cracking. cheap way to solve easy problems before spending a lot of money on something unnecessary- plus is aids in the 'process of elimination factor' Last edited by chev74; 10-26-2007 at 06:56 PM.

10-26-2007, 11:31 PM	#4
78chev Registered User Join Date: Feb 2007 Location: redondo beach california Posts: 84	Re: Transmission Squealing Get a big ol' cigar and do a smoke test.

10-29-2007, 05:23 PM	#5
crawdad Senior Member Join Date: Sep 2004 Location: Georgia Posts: 614	Re: Transmission Squealing I climbed back under the truck today to see if I could see anything out of the ordinary. I really need to get it up on a car rack to do any good however. The vacuum line to the modulator seems to be ok and is hooked up properly. I tried to pinpoint the location of the squeal a little more closely, and as far as I could tell (I'm about deaf , it seems to be coming more from the front of the tranny rather than the back, almost right up there next to the torque converter. When I shut if off, however, I'm still hearing that sound that sounds much like a vacuum bleed-off, for lack of a better term. Like I said earlier, the tranny pulls and shifts out very good, although the shift points are a little quick, so I hope it ain't getting ready to bite the dust on me. Is there anything "inside" of the transmission that could be making a squeal like that? __________________ 2012 Silverado LT 1500, 5.3, 6 speed auto '86 SWB C-10 Silverado

10-29-2007, 05:32 PM	#6
old Rusty C10 Robert Olson Transport Join Date: Oct 2002 Location: recent transplant to NC USA Posts: 20,310	Re: Transmission Squealing could there be a small hole in the metal part of the vacuum line? __________________ Bob 1951 International running on a squarebody chassis "If a man's worth is judged by the people he associates himself with, then i am the richest man in the world knowing some of the fine people of this board" http://67-72chevytrucks.com/vboard/a...t.php?f=25&a=9 (you can review the site rules here!) PM Me for your vehicle/parts hauling needs in the North East US or see my Facebook page Robert Olson Transport Live each day to the fullest.. you never know when fate is going to pull the rug out from under you... I hate cancer!!



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