Having problems with your 2005 GMC Sierra ?
I have a 05 sierra z71 5.3L when i start the
\015 I have a 05 sierra z71 5.3L when i start the truck i am getting a wicked rateling or knocking noise from the bellhousing. as i start to accelerate it goes away but at idle or low rpm it is there. it has gone away for a couple days then came back(a few different times). i was told that the starter was probably not returning all the way and the flywheel is hitting it causing the noise? any input would be very helpful thanks\015
Could be a starter sticking but that would cause more of a grinding noise, my best guess is that your flex-plate(flywheel) is broken if the noise is coming from between the engine and transmission. Remove the access cover for the bell housing and take a look at the flex-plate.
If it is the same knocking sound I experience on my 2002 GMC Sierra, it knocks when it is cold and appears to fade away if you increase rpm or as the truck warms up. I reviewed a GM bulletin a few years back and believe it indicated that some engines build up carbon on top of the pistons that cause the noise but GM indicates it is not detrimental to the engine. I would have "opted out" on that particular option if I had a choice. But on a good note, I have 160,000 on mine and it's still running strong. Oh, and still knocks on start up. Maybe this helps, just an FYI
Repair Help & Product Troubleshooting for 2005 GMC Sierra
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