2011 Chevrolet Traverse LS 3.6L V6 AWD 200000km
I recently noticed a new unusual thud sound when shifting from Park to Drive or Park to Reverse. No other sound or other issues observed. The sound is intermittent. The sound is louder when the car has sat for 5 to 10 min or longer. The sound is softer when the car is warm. Car shifts gears okay when driving. Car drives okay.
A month ago I drained and filled my transmission with the correct fluid. Yesterday I drained a quart of the ATF wih new ATF.
The last time transmission was serviced was at 90000km-95000km.
Today I just changed my power steering fluid.
I found melted (?) or damaged red wiring attached to a box next to the fuse box. It's not the battery. See pictures. When I changed my power steering fluid, I didn't put the engine cover back on.
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Does the motor jolt when you shift?
Check the motor mounts and drivetrain visually.
It could be an internal fault (usually accompanied by a delayed shift from N to R) but usually it’s just the transmission torque mount
speaking of driveline maintenance, make sure the driveshafts are lubed and in good working order: u-joints, slip-yokes, pinions, etc.
are you parked on an incline when you hear it?
Negative. Flat level surface.
well it's not the youngest transmission.
Have you been servicing the driveline? (differentials, transfer case, etc.)
Recently, transfer case fluid was changed. Differential fluids were inspected and I was told they looked cleaned. They were also regularly changed by previous owner, maybe every around 40000 to 80000 km not sure exactly.
maybe there is some binding on driveshaft joints, or loose suspension parts, loose transmission/motor mounts ...
How can I rule out my transmission? I have a scan tool that can read live data, hoping that will help?
scan tool is unlikely to help unfortunately. This will require eyeballs and dirty hands.
No jerk when I shifted. For some reason it hasn't at all jerked and made a thud sound for a day and a half. When draining and filling my ATF, I tried to be careful but could dirt or other foreign material in the transmission caused the intermittent thud? Thanks.
No unless you saw some big chunks come out when you drained it.
But air pockets might. Did you move the shift lever through all the positions after refilling, pausing a few seconds at each one?
No big chunks when I drained. There was fine metallic powder on drain plug but I heard that was normal (?). I did move the shift lever to all positions pausing a few seconds at each one. I did that 4 / 5 times
A little bit is normal. It comes from the clutch friction discs.
If there's so much that the fluid glitters then tranny is done.
It wasn't much to my estimation. Maybe a teaspoon or two. Anyways the symptom (thud and jerk) has not reappeared so I guess I'm good?
fingers crossed
🤞