Catharsis Posted August 29, 2019 Share Posted August 29, 2019 Hey all, I've recently started hearing some kind of intermittent grinding noise from my '05 LGT, seemingly more from the rear of the car. Originally I thought it was a wheel bearing or suspension issue, because it was happening at very low speeds when barely on the gas and the car was warm. Now it seems to also be happening when the vehicle is stopped and in gear also. I've still only heard the noise when the car is warm and has been driven for a little while (5-10 min). It doesn't seem to increase or decrease particularly when on or off the gas, but typically only happens at idle speed or just above. Any ideas on what this could be are welcome, all I can really think is that it's coming from the transmission or differential. Thanks! Sent from my ONEPLUS A6003 using Tapatalk Link to comment Share on other sites More sharing options...
Max Capacity Posted August 29, 2019 Share Posted August 29, 2019 Would have to guess, you have a loose heat shield on the exhaust some where. 305,600miles 5/2012 ej257 short block, 8/2011 installed VF52 turbo, @20.8psi, 280whp, 300ftlbs. (SOLD). CHECK your oil, these cars use it. Engine Build - Click Here Link to comment Share on other sites More sharing options...
Catharsis Posted August 29, 2019 Author Share Posted August 29, 2019 Would have to guess, you have a loose heat shield on the exhaust some where.I'll check around, thanks! Sent from my ONEPLUS A6003 using Tapatalk Link to comment Share on other sites More sharing options...
Notorious Posted August 29, 2019 Share Posted August 29, 2019 Auto or Manual? Link to comment Share on other sites More sharing options...
Catharsis Posted August 30, 2019 Author Share Posted August 30, 2019 Auto or Manual?5AT, I should have specified Sent from my ONEPLUS A6003 using Tapatalk Link to comment Share on other sites More sharing options...
schwab Posted August 30, 2019 Share Posted August 30, 2019 Check the exhaust hangars too. get under the car, cold exhaust or thick gloves, and rattle the exhaust system around. Luckily it doesn't sound like drive train. Link to comment Share on other sites More sharing options...
Notorious Posted August 31, 2019 Share Posted August 31, 2019 Are the CV axles OEM? Bad reman axles can often make a similar noise at a stop or low speed in an automatic Trans since there is constant force being applied to them. Link to comment Share on other sites More sharing options...
lvkeith Posted August 31, 2019 Share Posted August 31, 2019 Struggling with this in my 5eat right now. Started with a bad cv shaft and based on the grinding frequency and amplitude(unrelated to trans temp but related to freeway speeds) I purchased a new rear differential. The logic for me was that it happened intermittently under load and always related to freeway driving but would go away after some time below 45mph. After replacing the rear wheel bearings With bonresolve I’m moving toward the tapered bearings in the rear diff (pinion/carrier) starting to show signs through noise. Good luck buddy. Sent from my iPhone using Tapatalk Link to comment Share on other sites More sharing options...
Max Capacity Posted August 31, 2019 Share Posted August 31, 2019 lvkeith, How many crap is stuck to the magnetic drain plug on the rear diff ? What does your fluid look like ? Should come out fairly clean looking. 305,600miles 5/2012 ej257 short block, 8/2011 installed VF52 turbo, @20.8psi, 280whp, 300ftlbs. (SOLD). CHECK your oil, these cars use it. Engine Build - Click Here Link to comment Share on other sites More sharing options...
lvkeith Posted August 31, 2019 Share Posted August 31, 2019 There was some muck on the magnet. Using a borescope the pattern and tooth condition looked ok. Again for me, it isn't a constant problem. The intermittent ones are a little more difficult. Link to comment Share on other sites More sharing options...
Catharsis Posted September 13, 2019 Author Share Posted September 13, 2019 Thanks to everyone for the input! Turns out my exhaust was/is rattling off the rear sway bar at certain rpms. Weird since it never used to do it audibly, and nothing else around the area really changed. Sent from my ONEPLUS A6003 using Tapatalk Link to comment Share on other sites More sharing options...
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