Transmission or U-Joint? - The 1947 - Present Chevrolet & GMC Truck Message Board Network

garold99 · 12-21-2004, 04:54 PM

For most of the year I have had a noise off and on under my truck. I figured it was the U-joint next to the tranny going bad. So since I dont really drive this truck for extended period of times, I have been trying to put it off changing. Well a couple months ago I start getting some vibration when I hit between 40 and 70, so I usually stay around 40. Anyhow I figure its time to change the U-Joint before the drive shaft leaves me unexpectedly.

Well last couple weeks the noise has been more consistant, kinda like the bearing in the U-Joint tinging together. Today I drove it about 20 miles and when I got home I checked again on the noise. Now it sounds like its comming from the torque converter, or like a piece of metal sitting on my fly wheel. But it only happens when it is in gear, either D or R. This noise didnt really start till after I replaced the starter recently. Or at least it wasnt as loud or constant as now.

My question is this. What does a torque converter sound like or do if it is going bad? Or is this just a U-Joint problem and maybe the noise is transmitting through the metal to the front of the tranny?

I know sometimes the truck feels like my rear end is lower geared than it normally feels.

Thanks

67chevemall · 12-21-2004, 05:32 PM

Off the wall but,
shim or ? from the starter-Trany is going(torque converters are pretty bullet proof)
U joints front or back- carrier bearing gone- rear end is going.
??
$0.02

dons454s · 12-21-2004, 05:39 PM

is the converter shield or dust cover on wrong ???

7T2 · 12-21-2004, 06:36 PM

Any leaks? I had a mysterious noise in my Dodge that I could never track down. When I traded it in my friend (the service manager) told me that the front engine seal had come loose and was scraping against the crankshaft? (or some other moving part up there). I never did fully understand it, but it made a "jangling" sound sometimes, but not always.

mr402 · 12-21-2004, 07:06 PM

I'd get under there and start prying on those U-joints. If it was the torque converter the vibration would be more dependent on engine speed. If U-joints or rear end the vibration would vary by road speed. My personal experience with vibration has always ended with U-joint replacement.

poink 71 chev · 12-21-2004, 07:16 PM

you might also check yhe flex plate. I have seen them crack and they will rattle and sound almost like a rod knock.

garold99 · 12-21-2004, 08:28 PM

Quote:

Originally Posted by dons454s

is the converter shield or dust cover on wrong ???

ive owned this truck since 95 and its never had a fly wheel cover. if thats what your talking about. tranny was rebuilt in 99 and never had a problem with it.

garold99 · 12-21-2004, 08:31 PM

I will climb under it this weekend and change out the u-joint when the temps are supposed to be back up in the low 50's. While under there I will check for anything loose or cracked.

Thanks

kingsolver72 · 12-21-2004, 08:56 PM

U-joint is my guess.If you let a bad u-joint go too long before replacing you can do more damage.Possibly to the drive shaft.It is too cheap and easy of a fix to let it go.

lofly'a · 12-21-2004, 10:45 PM

check the flywheel for crack too...........

Longhorn Man · 12-21-2004, 11:18 PM

If it doesn't clank at an idle or low speeds, then 99% chance it is NOT in the tranny or fly wheel.
If you drip a front u-joint...or even a middle U-joint, you'r truck could do the pole volt thing, or just rip out the rear axle. Popping ANY U-joint at speed can cause the drive shaft to rip through the floor and join you in the cab.
If you blow onw in motion, and if you are lucky, all you'll need is a new driveshaft, but odds are, it'll kill something else to.

Sierra · 12-21-2004, 11:25 PM

Could be the u-joints. They are almost impossible to diagnose without a thorough road trip. They will definitely cause unwanted vibrations at certain speeds and make your driving experience a real challenge. I switched to Precision #280 U-joints a couple of years ago, and have had no more problems (so far).

garold99 · 12-22-2004, 12:26 AM

I really dont drive it much except around town. So I mainly only go about 25 or 30 mph. The speed limit around town is fairly low. Plus I rarely go over a few miles when I do go somewhere in the truck. Most of the time I just take the wifes car. Reason being my power steering bracket broke about a year ago and so the trucks not as fun to drive without power steering. Well that and no A/C.

I will be taking care of that U-Joint though before I do anymore driving, thats for sure. Dont need no drive shaft doing the scene from Alien and joining me in the cab.

12-21-2004, 04:54 PM	#1
garold99 Registered User Join Date: Nov 2004 Location: Moore, Oklahoma Posts: 129	Transmission or U-Joint? For most of the year I have had a noise off and on under my truck. I figured it was the U-joint next to the tranny going bad. So since I dont really drive this truck for extended period of times, I have been trying to put it off changing. Well a couple months ago I start getting some vibration when I hit between 40 and 70, so I usually stay around 40. Anyhow I figure its time to change the U-Joint before the drive shaft leaves me unexpectedly. Well last couple weeks the noise has been more consistant, kinda like the bearing in the U-Joint tinging together. Today I drove it about 20 miles and when I got home I checked again on the noise. Now it sounds like its comming from the torque converter, or like a piece of metal sitting on my fly wheel. But it only happens when it is in gear, either D or R. This noise didnt really start till after I replaced the starter recently. Or at least it wasnt as loud or constant as now. My question is this. What does a torque converter sound like or do if it is going bad? Or is this just a U-Joint problem and maybe the noise is transmitting through the metal to the front of the tranny? I know sometimes the truck feels like my rear end is lower geared than it normally feels. Thanks

12-21-2004, 10:45 PM	#10
lofly'a Registered User Join Date: May 2000 Location: Alexandria, LA 71301 Posts: 1,451	check the flywheel for crack too........... __________________ -02 avalanche (daily driver) -66 gto ragtop 389/400 (garage queen, hand-me-down from dad) -72 Tribute Trans Am (6.0LS/T56 6-speed) in progress -2003 YUKON (Wife's) -71 gmc swb fleet (current project, gonna shave everything, bags, stuff w/ 20's, gen III powertrain) -48 3100 SWB - 12/31/23 LONG TERM Project

12-21-2004, 05:32 PM	#2
67chevemall Registered User Join Date: Apr 2003 Location: NB Posts: 3,367	Off the wall but, shim or ? from the starter-Trany is going(torque converters are pretty bullet proof) U joints front or back- carrier bearing gone- rear end is going. ?? $0.02 __________________ 1968 Chevy C10 307 3ott fleetside 1967 Chevy C/10 V8, 3spd, fleetside lwb.Sold 1967 Chev C/10 step, 383, M21. SOLD

12-21-2004, 05:39 PM	#3
dons454s Registered User Join Date: Nov 2004 Location: Claysburg, Pa Posts: 408	is the converter shield or dust cover on wrong ???

12-21-2004, 06:36 PM	#4
7T2 Active Member Join Date: Dec 2004 Location: Marysville, OH Posts: 667	Any leaks? I had a mysterious noise in my Dodge that I could never track down. When I traded it in my friend (the service manager) told me that the front engine seal had come loose and was scraping against the crankshaft? (or some other moving part up there). I never did fully understand it, but it made a "jangling" sound sometimes, but not always.

12-21-2004, 07:06 PM	#5
mr402 Registered User Join Date: Jan 2004 Location: Elmira, Oregon Posts: 449	I'd get under there and start prying on those U-joints. If it was the torque converter the vibration would be more dependent on engine speed. If U-joints or rear end the vibration would vary by road speed. My personal experience with vibration has always ended with U-joint replacement.

12-21-2004, 07:16 PM	#6
poink 71 chev Registered User Join Date: Nov 2004 Posts: 55	you might also check yhe flex plate. I have seen them crack and they will rattle and sound almost like a rod knock.

12-21-2004, 08:31 PM	#8
garold99 Registered User Join Date: Nov 2004 Location: Moore, Oklahoma Posts: 129	I will climb under it this weekend and change out the u-joint when the temps are supposed to be back up in the low 50's. While under there I will check for anything loose or cracked. Thanks

12-21-2004, 08:56 PM	#9
kingsolver72 10/30/19 Join Date: Aug 2004 Location: ottawa kansas Posts: 5,248	U-joint is my guess.If you let a bad u-joint go too long before replacing you can do more damage.Possibly to the drive shaft.It is too cheap and easy of a fix to let it go.

12-21-2004, 11:18 PM	#11
Longhorn Man its all about the +6 inches Join Date: Jan 2001 Location: Hilliard Ohio Posts: 2,690	If it doesn't clank at an idle or low speeds, then 99% chance it is NOT in the tranny or fly wheel. If you drip a front u-joint...or even a middle U-joint, you'r truck could do the pole volt thing, or just rip out the rear axle. Popping ANY U-joint at speed can cause the drive shaft to rip through the floor and join you in the cab. If you blow onw in motion, and if you are lucky, all you'll need is a new driveshaft, but odds are, it'll kill something else to.

12-21-2004, 11:25 PM	#12
Sierra Registered User Join Date: Nov 2000 Location: Victoria, Texas Posts: 71	Could be the u-joints. They are almost impossible to diagnose without a thorough road trip. They will definitely cause unwanted vibrations at certain speeds and make your driving experience a real challenge. I switched to Precision #280 U-joints a couple of years ago, and have had no more problems (so far).

12-22-2004, 12:26 AM	#13
garold99 Registered User Join Date: Nov 2004 Location: Moore, Oklahoma Posts: 129	I really dont drive it much except around town. So I mainly only go about 25 or 30 mph. The speed limit around town is fairly low. Plus I rarely go over a few miles when I do go somewhere in the truck. Most of the time I just take the wifes car. Reason being my power steering bracket broke about a year ago and so the trucks not as fun to drive without power steering. Well that and no A/C. I will be taking care of that U-Joint though before I do anymore driving, thats for sure. Dont need no drive shaft doing the scene from Alien and joining me in the cab.



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