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Ask GM Tech (Cam) Your Own Question
GM Tech (Cam)
GM Tech (Cam), Pontiac Technician
Category: Pontiac
Satisfied Customers: 2375
Experience:  GM Grand Master Technician 2007. 14 years experience.
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Clunk clunk one night. next day taking off and it felt like

Customer Question

clunk clunk one night. next day taking off and it felt like someone hit the brakes hard twice. coasted down the road in neutral put it back in gear and no issue. this stared one day after the trans was rebuilt
JA: How many miles are on the car? Are these the orignial brakes?
Customer: 75k, no, not a brake issue
JA: What is the model/year of your Pontiac?
Customer: 2009 g6 gxp 3.6 v6
JA: Are you fixing your G6 yourself? What have you tried so far?
Customer: no. someone looked at catalytic converter plugged but it was not plugged
JA: Anything else you want the mechanic to know before I connect you?
Customer: no
Submitted: 4 months ago.
Category: Pontiac
Expert:  Chad Farhat replied 4 months ago.

Hi, I'm Chad. Welcome to JustAnswer. I'm reviewing your question and I will be posting your reply ASAP.

Expert:  Chad Farhat replied 4 months ago.

hey how are you

1- this is hard since i can not hear it

but if the cv axle shaft Nut got loose and they had to pull the axles to do the trasnmission rebuild that could be causing the clunk and will be more eveident on the stoping more since it will move and causing the cliunk .

2- have you had it lifted on ca rlift and inpect the under carraiage ,situation like this you need a visual inspection,but based on what you mentioned that is a big possibility and i seen it happened if the axle shaft nut was not torqued to specs,but testing will be needed

3- any suspension part coul do that ,lower & upper ball joint ,links ,etc

4- the transmission itself that was rebuild needs also inpected if it happened after ,in case related

Please let me know

Thank You

Chad Farhat

ASE Certified Technician

Customer: replied 4 months ago.
the trans guy looked at it and said it is an motor or running issue nothing wrong with the trans rebuild. he thought the converter was plugged he removed the converter and tried to restart and still had running problems. wouldn't start, rough idle. when i had the car after the trans rebuild. the nest day when starting to take off a heard a load clunk sounded like i ran over a large boulder. went 1 mile home no other issues. the next day drove 10 mile to work right before getting to work I started to take off and it felt like someone pressed the bakes to a stop, put in nuetral, took off again with same result. turned on to side road an coasted to the bottom of a hill. stopped put back into gear and it drove ok 1 mile to work. drove 10 miles to park car for towing to trans shop. Trans guy took over from there
Expert:  Chad Farhat replied 4 months ago.

With a proper GM scanner he can retrieve pending or history fault codes ?

is there any warning light on dash ,check engine light on , abs light ,tcs light etc?

it could be engine related but we need more evidence

from what you describing ,if really the brakes locked up then it could be an ABS issue .

there is no know issue from what you describing , did you have that problem prior to the trans rebuild or it happened as soon as you got it back ,if it did

big chance it has something to do with he repairs could be not the trans but of he missed a ground wire loose and causing this intermittent issue

Please let me know if you need anything else

Thank You

Chad Farhat

ASE Certified Technician