Crazy popping sound underneath. - The 1947 - Present Chevrolet & GMC Truck Message Board Network

barn9 · 05-30-2002, 08:07 PM

At first I thought it was a U-joint or the carrier bearing, but a couple times when just getting into the truck, I hear this loud pop. I crawled under yesterday and noticed that the driver side cab mount looks a little funky and it made me wonder if that rubber being a little collapsed could let something move enough to make that popping sound. It sounds like a metal on metal pop to me. Anyone ever had anything comparable? Or should I just start replacing U-joints and posssibly the carrier bearing. They do all have some age and miles on them, so I'm thinking of just going through and changing them anyway. But the popping is making me scratch my head as to the cause. Thanks for any insights you guys might have, LB.

*Fast68Chevy* · 05-30-2002, 09:53 PM

cab mount popping makes ore sense than anything else, why would anything else pop wen you just get in the truck

BLACK AND BLUE 67-72 · 05-30-2002, 10:27 PM

Is it 4 Wheel Drive? If so it could be the front leaf spring bolt hitting the inner fender well and popping off the edge. If 2 Wheel Drive it could be a cab mount or suspension related.

barn9 · 05-31-2002, 01:06 AM

It's 2 wheel drive, and the sound seems to be coming from area under back end of the cab. I went back and forth a few times in the street with my neighbor walking alongside, and then he drove while I listened, and (murphy's law) not a fricken peep! I have never changed or even touched a cab mount before, any tips would be appreciated! Just from the look of it, I wouldn't think it needs replacing, even though it shows age, but if that turns out to be the problem, it will be done.

**68 Stepside** · 05-31-2002, 01:16 AM

rear trans mount ok? just an idea.

Big69C20 Toy · 05-31-2002, 01:17 AM

cab mounts are easy, one of the first thing i did on my truck, even though it didnt need it. Just undo the bolts and stuff should come out. yer bolts might be fubar (hope not) cuz the kit i bought didnt come with new bolts. Anyways just get a nice wood block on yer jack and loosen all the cab mounts, lift one side up and switch out bushings, easy stuff! then follow same on other side.

OhioDan · 05-31-2002, 03:40 AM

I had a dry ball joint one time that would make a popping noise. Shot some grease to it, and the popping went away. My $.02

Tink · 05-31-2002, 07:11 AM

The cab mounts on my S10 were bad... (they looked squished) and it would make a popping sound that came from the rear of the cab.

BigJackDaddy · 05-31-2002, 08:56 AM

How do the shock bushings look?

texnician01 · 05-31-2002, 10:45 AM

it wouldn't surpise me if the cab mount rubber was soft and the pop that you hear is the theads on the bolt rubbing against the frame or the washers as the mount compresses. take a piece of sheetmetal and run the threads of a bolt across the edge of the metal. see if it makes a simmilar sound.

Nathan

barn9 · 05-31-2002, 11:02 AM

Really appreciate the help guys! Front end parts, shocks, etc. are all in excellent condition and well maintained. The cab mount is the prime suspect, but I'm going to give the U-joints a close inspection, and check tranny mount, etc. just to be sure. Where's the best place, read that best price, to get cab bushings? Thanks again everyone, it is so great to have this board for these situations.

Southpa · 05-31-2002, 01:22 PM

I had similar noises coming from underneath years ago, mostly while turning out of my driveway. It turned out to be one of the frame crossmembers needed to be tightened up. If you DO find that is the problem, take the offending bolt out and inspect it for wear, also the edges of the hole where it came from.

05-30-2002, 08:07 PM	#1
barn9 Half a bubble off! Join Date: Jun 2000 Location: Winfield, Ks, USA Posts: 5,588	Crazy popping sound underneath. At first I thought it was a U-joint or the carrier bearing, but a couple times when just getting into the truck, I hear this loud pop. I crawled under yesterday and noticed that the driver side cab mount looks a little funky and it made me wonder if that rubber being a little collapsed could let something move enough to make that popping sound. It sounds like a metal on metal pop to me. Anyone ever had anything comparable? Or should I just start replacing U-joints and posssibly the carrier bearing. They do all have some age and miles on them, so I'm thinking of just going through and changing them anyway. But the popping is making me scratch my head as to the cause. Thanks for any insights you guys might have, LB. __________________ Just call me LB. '71 Cheyenne, 402BB, hauls blondes, brunettes, or redheads.

05-30-2002, 10:27 PM	#3
BLACK AND BLUE 67-72 Firefighter Join Date: Feb 2001 Location: Yellville, Ar, USA Posts: 1,943	Is it 4 Wheel Drive? If so it could be the front leaf spring bolt hitting the inner fender well and popping off the edge. If 2 Wheel Drive it could be a cab mount or suspension related. __________________ '72 Chevy SWB 350 Auto '67 GMC LWB 350 4 speed '70 Chevy 4x4 Stepside 350 Auto Yellville, Ar. USA

05-31-2002, 01:06 AM	#4
barn9 Half a bubble off! Join Date: Jun 2000 Location: Winfield, Ks, USA Posts: 5,588	It's 2 wheel drive, and the sound seems to be coming from area under back end of the cab. I went back and forth a few times in the street with my neighbor walking alongside, and then he drove while I listened, and (murphy's law) not a fricken peep! I have never changed or even touched a cab mount before, any tips would be appreciated! Just from the look of it, I wouldn't think it needs replacing, even though it shows age, but if that turns out to be the problem, it will be done. __________________ Just call me LB. '71 Cheyenne, 402BB, hauls blondes, brunettes, or redheads.

05-31-2002, 01:16 AM	#5
68 Stepside huh? Join Date: May 2000 Location: Washington, Illinois Posts: 5,690	rear trans mount ok? just an idea. __________________ Someday when I'm lonely, Wishing you weren't so far away, Then I will remember Things we said today. RIP El Jay

05-31-2002, 01:17 AM	#6
Big69C20 Toy Livin' it up. Join Date: Nov 2001 Location: Richland, MI Posts: 2,212	cab mounts are easy, one of the first thing i did on my truck, even though it didnt need it. Just undo the bolts and stuff should come out. yer bolts might be fubar (hope not) cuz the kit i bought didnt come with new bolts. Anyways just get a nice wood block on yer jack and loosen all the cab mounts, lift one side up and switch out bushings, easy stuff! then follow same on other side. __________________ -Greg; Sold the 69 C20. It's off to a better home with more love! Now onto the 86 CUCV M1009; K5 blazer with 6.2L diesel, corp 10 bolt axles, Detroit locker in the rear, trutrac front, 3.73 gears, 35" tires.

05-30-2002, 09:53 PM	#2
Fast68Chevy Account Suspended Join Date: May 2000 Location: IL Posts: 0	cab mount popping makes ore sense than anything else, why would anything else pop wen you just get in the truck

05-31-2002, 03:40 AM	#7
OhioDan Registered User Join Date: Apr 2002 Location: New Carlisle, Ohio,USA Posts: 1,404	I had a dry ball joint one time that would make a popping noise. Shot some grease to it, and the popping went away. My $.02 __________________ LIFE AIN'T EASY WHEN YER FAT AND GREASY! GMC= Got More Class! 1970 GMC LWB, Fleetside, 350/4spd, Flowmaster "40's", 2002 GMC 16" Rallies, cowl hood,and added a bunch of options that weren't there when I started.

05-31-2002, 07:11 AM	#8
Tink Registered User Join Date: May 2002 Location: VA Posts: 1,337	The cab mounts on my S10 were bad... (they looked squished) and it would make a popping sound that came from the rear of the cab. __________________ 69 Chevy C10 88 Sierra 02 2500 Suburban And too many S10s to list!

05-31-2002, 08:56 AM	#9
BigJackDaddy Registered User Join Date: Sep 2000 Location: Falcon, CO Posts: 194	How do the shock bushings look? __________________ ColoradoMelons.com

05-31-2002, 10:45 AM	#10
texnician01 Senior Member Join Date: Mar 2002 Location: 12 Miles South of Des Moines, Iowa Posts: 359	it wouldn't surpise me if the cab mount rubber was soft and the pop that you hear is the theads on the bolt rubbing against the frame or the washers as the mount compresses. take a piece of sheetmetal and run the threads of a bolt across the edge of the metal. see if it makes a simmilar sound. Nathan __________________ 69 C-10, 340HP 327 55 chevy 4 door 150 47 Willys CJ-2A 05 Harley Night Train 06 1200 Sportster (Wife's bike) 70 Honda CL350 OIF2 & OIF7 Veteran Nathan & Tiffany

05-31-2002, 11:02 AM	#11
barn9 Half a bubble off! Join Date: Jun 2000 Location: Winfield, Ks, USA Posts: 5,588	Really appreciate the help guys! Front end parts, shocks, etc. are all in excellent condition and well maintained. The cab mount is the prime suspect, but I'm going to give the U-joints a close inspection, and check tranny mount, etc. just to be sure. Where's the best place, read that best price, to get cab bushings? Thanks again everyone, it is so great to have this board for these situations. __________________ Just call me LB. '71 Cheyenne, 402BB, hauls blondes, brunettes, or redheads.

05-31-2002, 01:22 PM	#12
Southpa Registered User Join Date: May 2000 Location: Victoria, BC, Canada Posts: 2,409	I had similar noises coming from underneath years ago, mostly while turning out of my driveway. It turned out to be one of the frame crossmembers needed to be tightened up. If you DO find that is the problem, take the offending bolt out and inspect it for wear, also the edges of the hole where it came from. __________________ 1970 GMC 1500 Custom Original 350/TH350 Victoria, BC, Canada You can wish in one hand and crap in the other. See which one gets filled first.



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