Thumping noise?!? - The 1947 - Present Chevrolet & GMC Truck Message Board Network

todds3535 · 01-03-2005, 06:26 PM

Wondering if anyone can help me out with this one...I have an '87 K5 Blazer that I bought about 8 months ago, when I first bought it I checked it out as much as I could and the 4 wheel drive seemed to work ok. I really havn't needed it until a couple weeks ago when we got dumped on with about 6-8 inches of snow. So I put it in 4 wheel and take off from a stop sign and get this loud thumping from what sounds like the right front passenger floorboard.
I first thought it was the wheel hopping, but I can't be sure.
After disengaging 4 wheel drive it went away and I brought the truck back home and checked it out, nothing seemed loose or anything. But I havn't driven it in 4 wheel since this happened.

Any help is appreciated and thanks in advance.

Todd

Mudder · 01-03-2005, 07:10 PM

If it has a lift on it the first thing I would check is the driveshaft. Could be the chain in the transfercase slipping. Does it stop making the noise after you get going? More info..... needed.

clarkjw24 · 01-03-2005, 07:13 PM

Either a bad ujoint or cv joint in you front drive shaft. If its got any lift the driveshaft prob should have been "clearance" around the cv ears for more angle. Your hearing the front drive shaft wobble or pop. Check the ujoints and the cv nuckle and that should fix you.

todds3535 · 01-03-2005, 07:31 PM

Blazer is still stock, suspension, axles etc. But I did plan on lifting it this spring. ( I don't have a garage)

It does stop after I reach about 30mph. Seems like it is just from a stop, when I accelerate in 4wd I noticed it for the first time.

I bought it for $800, and I did plan on fixing it up for a daily driver. And maybe some 4 wheelin' on the weekends. It runs and drives great and the body is not beyond repair. Just hoping it isn't too expensive...I'm laid off right now and don't have a ton of money right now.

LONGHAIR · 01-03-2005, 07:40 PM

It is most likely the front drive shaft (CV joint). It could be in the axle joints too...but usually when they get bad they go stiff. This will result in the steering wheel jerking.

todds3535 · 01-03-2005, 08:05 PM

I'll check the cv and axle joints out tomorrow. And take a look at the driveshaft. My trouble is I live in a trailer park ( or Mobile Home community to be politically correct ) and my damn land lord gets pissed everytime I lift my hood to check my oil.

Help is greatly appreciated, you guys are great.

If you pass through the S.E. Mich area look me up and I'll buy y'all a cold one.

Americanrider · 01-04-2005, 12:05 AM

Does it have the factory Auto-hubs? If so the tend to get gummed up and will sometimes slip out making a racket.

todds3535 · 01-04-2005, 12:10 AM

rider,
Yea, it has the factory auto locs. Is there a way to prevent this slipping from happening?

todds3535 · 01-04-2005, 09:06 AM

I guess to assure they don't slip again, I'll replace the auto's w\ a set of Warn manuals when I do the lift in the spring.

Thanks for the help.

Mudder · 01-04-2005, 09:07 AM

Even if the auto hubs arent your problem I would change them out with manual lockouts when you get back to work. I never trusted them.

**JIMs70GMC** · 01-04-2005, 09:10 AM

A friend of mine had a bad clunking noise in 4wd and it was because a PO had swapped the tranny/transfercase and used the original crossmember and the cv was hitting the crossmember.
You need to rotate the front driveshaft by hand w/ the front off the ground and see what kind of play you have.

todds3535 · 01-04-2005, 09:44 AM

Thanks a lot for the suggestions. Very much appreciated. I'll go over the whole thing in the spring when the weather breaks.

Just checked the weather,

We have a severe weather advisory until Thursday afternoon with snowfall reaching 6-10" and then turning to sleet and freezing rain.

**JIMs70GMC** · 01-04-2005, 10:36 AM

Ah, suck it up and go lay in the snow.

It suppose to be 71 here today.

todds3535 · 01-04-2005, 11:34 AM

I'm not complaining, lived here all my life. I don't mind just snow, it's the sleet & freezing crap I can do without.

71 huh? Lucky you.

Have a good one.

01-03-2005, 06:26 PM	#1
todds3535 Registered User Join Date: Mar 2004 Location: Michigan Posts: 142	Thumping noise?!? Wondering if anyone can help me out with this one...I have an '87 K5 Blazer that I bought about 8 months ago, when I first bought it I checked it out as much as I could and the 4 wheel drive seemed to work ok. I really havn't needed it until a couple weeks ago when we got dumped on with about 6-8 inches of snow. So I put it in 4 wheel and take off from a stop sign and get this loud thumping from what sounds like the right front passenger floorboard. I first thought it was the wheel hopping, but I can't be sure. After disengaging 4 wheel drive it went away and I brought the truck back home and checked it out, nothing seemed loose or anything. But I havn't driven it in 4 wheel since this happened. Any help is appreciated and thanks in advance. Todd

01-03-2005, 07:13 PM	#3
clarkjw24 I like cheese Join Date: Aug 2004 Location: McBee, SC Posts: 192	Either a bad ujoint or cv joint in you front drive shaft. If its got any lift the driveshaft prob should have been "clearance" around the cv ears for more angle. Your hearing the front drive shaft wobble or pop. Check the ujoints and the cv nuckle and that should fix you. __________________ Cruiser: 1972 K5, 400/TH350/NP205, D44 and 12Bolt, 35 TSLs. Trail rig: 86 K5, 350 TBI, SM465/NP205, 5.13s, 14ff locked, h1 beadlocks, 42" TSLs, 64" rears, 56" fronts, D60 locked, 35pline, drive flanges, crossover, hydro assist, OBA. Tow rig: 2002 F350 PSD CC Dually FX4, chipped, cold air intake, BFGs

01-03-2005, 07:31 PM	#4
todds3535 Registered User Join Date: Mar 2004 Location: Michigan Posts: 142	Blazer is still stock, suspension, axles etc. But I did plan on lifting it this spring. ( I don't have a garage) It does stop after I reach about 30mph. Seems like it is just from a stop, when I accelerate in 4wd I noticed it for the first time. I bought it for $800, and I did plan on fixing it up for a daily driver. And maybe some 4 wheelin' on the weekends. It runs and drives great and the body is not beyond repair. Just hoping it isn't too expensive...I'm laid off right now and don't have a ton of money right now. Attached Images

01-04-2005, 09:10 AM	#11
JIMs70GMC user # 2756 Join Date: Jun 2001 Location: Chesapeake, Virginia Posts: 4,612	A friend of mine had a bad clunking noise in 4wd and it was because a PO had swapped the tranny/transfercase and used the original crossmember and the cv was hitting the crossmember. You need to rotate the front driveshaft by hand w/ the front off the ground and see what kind of play you have. __________________ 1970 K25, 8' stepside bed 350/465/205 44 up front, 60 in the rear 4.10s rolling on 33" Dunlop MTs 1986 K5, 350/465/208 Dana 60/14 bolt from a cucv 36" Super Swampers TSL/SX 1983 K20 w/ CUCV axles, 350/700R4/208 sitting on 37" Goodyears 1986 M1031 6.2 diesel, TH400/NP205 locker in the rear and a LS in the front, all stock for now..... 1986 K30, 350/400/205 dana 60 and 14 bolt. I kept the drivetrain. Body/bad and chassis are gone. 1981 K30, 350/465/205 dana 60 and dually 14 bolt. Has a G80, and a flat bed. Going to replace the flat bed. 1985 K20, 350/400/208 10 bolt and SF 14 bolt. I wonder where I can find some 1 tons. Hmmmmm

01-04-2005, 10:36 AM	#13
JIMs70GMC user # 2756 Join Date: Jun 2001 Location: Chesapeake, Virginia Posts: 4,612	Ah, suck it up and go lay in the snow. It suppose to be 71 here today. __________________ 1970 K25, 8' stepside bed 350/465/205 44 up front, 60 in the rear 4.10s rolling on 33" Dunlop MTs 1986 K5, 350/465/208 Dana 60/14 bolt from a cucv 36" Super Swampers TSL/SX 1983 K20 w/ CUCV axles, 350/700R4/208 sitting on 37" Goodyears 1986 M1031 6.2 diesel, TH400/NP205 locker in the rear and a LS in the front, all stock for now..... 1986 K30, 350/400/205 dana 60 and 14 bolt. I kept the drivetrain. Body/bad and chassis are gone. 1981 K30, 350/465/205 dana 60 and dually 14 bolt. Has a G80, and a flat bed. Going to replace the flat bed. 1985 K20, 350/400/208 10 bolt and SF 14 bolt. I wonder where I can find some 1 tons. Hmmmmm

01-03-2005, 07:10 PM	#2
Mudder Registered User Join Date: Feb 2001 Location: East Central, MO Posts: 11,339	If it has a lift on it the first thing I would check is the driveshaft. Could be the chain in the transfercase slipping. Does it stop making the noise after you get going? More info..... needed.

01-03-2005, 07:40 PM	#5
LONGHAIR just can't cover up my redneck Join Date: May 2004 Location: Columbus OH Posts: 11,414	It is most likely the front drive shaft (CV joint). It could be in the axle joints too...but usually when they get bad they go stiff. This will result in the steering wheel jerking.

01-03-2005, 08:05 PM	#6
todds3535 Registered User Join Date: Mar 2004 Location: Michigan Posts: 142	I'll check the cv and axle joints out tomorrow. And take a look at the driveshaft. My trouble is I live in a trailer park ( or Mobile Home community to be politically correct ) and my damn land lord gets pissed everytime I lift my hood to check my oil. Help is greatly appreciated, you guys are great. If you pass through the S.E. Mich area look me up and I'll buy y'all a cold one.

01-04-2005, 12:05 AM	#7
Americanrider Registered User Join Date: Dec 2004 Location: NW, WA. Posts: 1,421	Does it have the factory Auto-hubs? If so the tend to get gummed up and will sometimes slip out making a racket.

01-04-2005, 12:10 AM	#8
todds3535 Registered User Join Date: Mar 2004 Location: Michigan Posts: 142	rider, Yea, it has the factory auto locs. Is there a way to prevent this slipping from happening?

01-04-2005, 09:06 AM	#9
todds3535 Registered User Join Date: Mar 2004 Location: Michigan Posts: 142	I guess to assure they don't slip again, I'll replace the auto's w\ a set of Warn manuals when I do the lift in the spring. Thanks for the help.

01-04-2005, 09:07 AM	#10
Mudder Registered User Join Date: Feb 2001 Location: East Central, MO Posts: 11,339	Even if the auto hubs arent your problem I would change them out with manual lockouts when you get back to work. I never trusted them.

01-04-2005, 09:44 AM	#12
todds3535 Registered User Join Date: Mar 2004 Location: Michigan Posts: 142	Thanks a lot for the suggestions. Very much appreciated. I'll go over the whole thing in the spring when the weather breaks. Just checked the weather, We have a severe weather advisory until Thursday afternoon with snowfall reaching 6-10" and then turning to sleet and freezing rain.

01-04-2005, 11:34 AM	#14
todds3535 Registered User Join Date: Mar 2004 Location: Michigan Posts: 142	I'm not complaining, lived here all my life. I don't mind just snow, it's the sleet & freezing crap I can do without. 71 huh? Lucky you. Have a good one.



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