more trouble...front end - The 1947 - Present Chevrolet & GMC Truck Message Board Network

89blacksub · 03-17-2005, 05:40 PM

well it seems as though the front end is acting up now. me and a buddie were sitting in the truck at work and he wanted to see if the 4x4 would actually engage. so i put the tranny in nuetral and he shifted the lever to 4 hi and then i pulled forward a few feet then back to where i was. then we took it out of 4 hi and i reversed it for about 20 feet to make sure that the auto hubs ulocked. later i left work and started heading home. around 30 MPH the right side of the truck started making a sound almost like that made by a kid with a card in his bike spokes. it would stay that way till i stopped. and everytime i stopped there would be a thump-thump and i could feel the struck thumping. i figured maybe the hubs didnt come all the way unlocked but after revearsing for what had to be close to 200 total yards...the same situation. and the thumping when i stop only happens if i go past 30 and the noise starts up again. i dont know what to do...let me know what you think.

redz 1970 K5 · 03-17-2005, 06:02 PM

Judging by the sound, your problem shouldn't be too hard to diagnose. The louder and more severe the sound, typically the easier the diagnosis.

I have had similar sounds when one of the brake caliper bolts came off and the caliper was flopping around (many years ago), but that may or may not be right.

Maybe your u-joint has had it and the axle shaft is hitting the diff housing or spindle? There is also a needle spindle bearing that may have broken, and that would cause the shaft to contact the spindle and thump around.

Are you sure that the linkage to the tcase is setup properly, and that it truly was out of 4hi? Maybe it was still in 4hi and didn't disengage correctly.

Even if the hub was still engaged I am assuming it's an open diff, and it should still not make a thumping sound even if it is engaged- it should still rotate smoothly and quietly at 30mph. Sounds like something else.

Is there any vibration, or just a thump?

Just thinking out loud here...

89blacksub · 03-17-2005, 06:10 PM

its just a thump. also i forgot to add that the sound goes away after the thump even if i havent come to a "complete" stop yet.

89blacksub · 03-17-2005, 10:10 PM

as long as i am careful can i still drive it, or is that a really bad idea?? and could someone tell me how to take the hubs off, i am going to try and clean them and put them back on until i can get some manuals

03-17-2005, 05:40 PM	#1
89blacksub army slave Join Date: Feb 2005 Location: FT Hood, Texas Posts: 89	more trouble...front end well it seems as though the front end is acting up now. me and a buddie were sitting in the truck at work and he wanted to see if the 4x4 would actually engage. so i put the tranny in nuetral and he shifted the lever to 4 hi and then i pulled forward a few feet then back to where i was. then we took it out of 4 hi and i reversed it for about 20 feet to make sure that the auto hubs ulocked. later i left work and started heading home. around 30 MPH the right side of the truck started making a sound almost like that made by a kid with a card in his bike spokes. it would stay that way till i stopped. and everytime i stopped there would be a thump-thump and i could feel the struck thumping. i figured maybe the hubs didnt come all the way unlocked but after revearsing for what had to be close to 200 total yards...the same situation. and the thumping when i stop only happens if i go past 30 and the noise starts up again. i dont know what to do...let me know what you think. __________________ 1989 suburban 1500 4X4 silverado all stock...for now. plans; 6 inch susp lift 36" tires on 15" rims new all black paint custom bumbers misc engine mods until it goes, then drop in 454 nerf step bars billet grill ...

03-17-2005, 06:02 PM	#2
redz 1970 K5 OBS guy Join Date: Jun 2004 Location: SoCal Posts: 1,060	Judging by the sound, your problem shouldn't be too hard to diagnose. The louder and more severe the sound, typically the easier the diagnosis. I have had similar sounds when one of the brake caliper bolts came off and the caliper was flopping around (many years ago), but that may or may not be right. Maybe your u-joint has had it and the axle shaft is hitting the diff housing or spindle? There is also a needle spindle bearing that may have broken, and that would cause the shaft to contact the spindle and thump around. Are you sure that the linkage to the tcase is setup properly, and that it truly was out of 4hi? Maybe it was still in 4hi and didn't disengage correctly. Even if the hub was still engaged I am assuming it's an open diff, and it should still not make a thumping sound even if it is engaged- it should still rotate smoothly and quietly at 30mph. Sounds like something else. Is there any vibration, or just a thump? Just thinking out loud here... __________________ 88 Suburban Goodies- Alpine, Auto Meter, BDS, Bilstein, B&M, BFG, Borgeson, Bushwhacker, Cowl hood, Flowmaster, Genuine Gear, Holley, Infinity, JVC, K&N, MB Wheels, MSD, Pioneer, Skyjacker, Sony, Thorley, Walker + more Last edited by redz 1970 K5; 03-17-2005 at 06:06 PM.

03-17-2005, 06:10 PM	#3
89blacksub army slave Join Date: Feb 2005 Location: FT Hood, Texas Posts: 89	its just a thump. also i forgot to add that the sound goes away after the thump even if i havent come to a "complete" stop yet. __________________ 1989 suburban 1500 4X4 silverado all stock...for now. plans; 6 inch susp lift 36" tires on 15" rims new all black paint custom bumbers misc engine mods until it goes, then drop in 454 nerf step bars billet grill ...

03-17-2005, 10:10 PM	#4
89blacksub army slave Join Date: Feb 2005 Location: FT Hood, Texas Posts: 89	as long as i am careful can i still drive it, or is that a really bad idea?? and could someone tell me how to take the hubs off, i am going to try and clean them and put them back on until i can get some manuals __________________ 1989 suburban 1500 4X4 silverado all stock...for now. plans; 6 inch susp lift 36" tires on 15" rims new all black paint custom bumbers misc engine mods until it goes, then drop in 454 nerf step bars billet grill ...

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