Need help diagnosing problem - The 1947 - Present Chevrolet & GMC Truck Message Board Network

Madbomber88 · 08-31-2004, 06:20 PM

I have a problem with my rear end... Nice intro huh?

Only when I am starting from a stop, with the wheel turned anything but straight, in other words, this only happens when I am pulling onto a road.
Something in the rear is binding or whatever, and it clunks for the first few seconds of the acceleration, but it is pretty hefty because it feels like it is kicking the whole rear of the truck from side to side until it frees up. This doesn't happen if I am starting from a stop and going straight.
It's a 71 K5 CST, no lift, SM465, 350 stock

Any ideas?

bouncytruck · 08-31-2004, 07:13 PM

Do you have a posi rear? Have you checked the fluid level in the differential?

Madbomber88 · 08-31-2004, 09:47 PM

I have no idea if it is a posi. Is there a way to check without pulling the cover? I do need to check the fluid though. Could it be that simple and also be the reason for the noise??

Aarons'72Blaz · 08-31-2004, 11:21 PM

if it is a possi you might need a possi additive. if it isn't your spider gears could be striped or broken. best bet is pull the cover and have a look. the longer you drive it the worst it will get.

bouncytruck · 09-01-2004, 11:43 AM

I would pull the cover and take a look. Sounds like it could use a fluid change anyway. It might just be low on fluid or be gummed up. How long have you owned the rig?

I think there is a way to tell buy either the codes on the glove box or the tag on the diff cover if it is a posi (factory anyway).

Aarons'72Blaz - welcome to the board. Take a minute to fill out your profile so we all know where you are

I think

Big J · 09-01-2004, 04:00 PM

Is it a clunky noise or a more precise ratcheting noise? It almost sounds like you might have a lockrite in the rear diff. Its a posi unit that fits inside the rear diff and replaces the spider gears. Your probably going to have to pull the cover. It never hurts to change the fluid anyway. You can pick up the gear oil and additive (if you have a factory posi) at any parts place. Advanced auto is the cheapest around here.

Madbomber88 · 09-01-2004, 07:19 PM

I haven't pulled the cover yet but I do now know that it came from the factory with a Posi unit. Does that help any? I would say the noise is most similar to a binding noise, kind of hard to explain, It appears to be coming from the left side more than the passenger side but that may just be because that's where I sit...

LUV2XCLR8 · 09-01-2004, 07:52 PM

LOOKS LIKE UR GONNA HAVE TO PULL THE COVER

08-31-2004, 06:20 PM	#1
Madbomber88 Active Member Join Date: Mar 2004 Location: Virginia Posts: 169	Need help diagnosing problem I have a problem with my rear end... Nice intro huh? Only when I am starting from a stop, with the wheel turned anything but straight, in other words, this only happens when I am pulling onto a road. Something in the rear is binding or whatever, and it clunks for the first few seconds of the acceleration, but it is pretty hefty because it feels like it is kicking the whole rear of the truck from side to side until it frees up. This doesn't happen if I am starting from a stop and going straight. It's a 71 K5 CST, no lift, SM465, 350 stock Any ideas? __________________ 71 Blazer CST 72 K20 Capt USAF

08-31-2004, 07:13 PM	#2
bouncytruck SKINNY TIRES RULE! Join Date: Sep 2001 Location: Bothell, WA Posts: 11,049	Do you have a posi rear? Have you checked the fluid level in the differential? __________________ bouncytruck 1972 K5 The Hauler 1994 K1500 Suburban The Daily2010 Kia Soul Wife's Ride2014 Fiat 500L

08-31-2004, 09:47 PM	#3
Madbomber88 Active Member Join Date: Mar 2004 Location: Virginia Posts: 169	I have no idea if it is a posi. Is there a way to check without pulling the cover? I do need to check the fluid though. Could it be that simple and also be the reason for the noise?? __________________ 71 Blazer CST 72 K20 Capt USAF

09-01-2004, 11:43 AM	#5
bouncytruck SKINNY TIRES RULE! Join Date: Sep 2001 Location: Bothell, WA Posts: 11,049	I would pull the cover and take a look. Sounds like it could use a fluid change anyway. It might just be low on fluid or be gummed up. How long have you owned the rig? I think there is a way to tell buy either the codes on the glove box or the tag on the diff cover if it is a posi (factory anyway). Aarons'72Blaz - welcome to the board. Take a minute to fill out your profile so we all know where you are I think __________________ bouncytruck 1972 K5 The Hauler 1994 K1500 Suburban The Daily2010 Kia Soul Wife's Ride2014 Fiat 500L

09-01-2004, 04:00 PM	#6
Big J Its lookin' like a Blazer! Join Date: Aug 2003 Location: Gods Country, KY Posts: 1,773	Is it a clunky noise or a more precise ratcheting noise? It almost sounds like you might have a lockrite in the rear diff. Its a posi unit that fits inside the rear diff and replaces the spider gears. Your probably going to have to pull the cover. It never hurts to change the fluid anyway. You can pick up the gear oil and additive (if you have a factory posi) at any parts place. Advanced auto is the cheapest around here. __________________ BAZINGA! My Build

08-31-2004, 11:21 PM	#4
Aarons'72Blaz Registered User Join Date: Aug 2004 Location: Brea, CA. Posts: 5	if it is a possi you might need a possi additive. if it isn't your spider gears could be striped or broken. best bet is pull the cover and have a look. the longer you drive it the worst it will get.

09-01-2004, 07:19 PM	#7
Madbomber88 Active Member Join Date: Mar 2004 Location: Virginia Posts: 169	I haven't pulled the cover yet but I do now know that it came from the factory with a Posi unit. Does that help any? I would say the noise is most similar to a binding noise, kind of hard to explain, It appears to be coming from the left side more than the passenger side but that may just be because that's where I sit... __________________ 71 Blazer CST 72 K20 Capt USAF

09-01-2004, 07:52 PM	#8
LUV2XCLR8 The LuvShack Garage Join Date: Jan 2004 Location: Maple Grove, TN (West Side) Posts: 30,475	LOOKS LIKE UR GONNA HAVE TO PULL THE COVER __________________ Owner/Op: "TN Classic Transport Carriers" The Toy: "Square Vette" 72 Hybrid Blazer Toy Barn: "LuvShack" 40 x 60 x 20 Shop Big Piggy: "Goliath" 07 Kodiak C4500 Lil Piggy:"Maddy" 88 Silverado 3500 Hauler: "Feathers" 14 Aluma 8218T



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