Here's a bit of a weird one...
This is for a 2003 FWD automatic with about 209k miles on it.
Lately I've been hearing a slight whine from the engine/transmission when I put my car into drive or reverse soon after a cold start. When accelerating, a sort of chugging/chain can also be heard. The behavior stops as the car gets to operating temperature.
I suspect that it has to do with the transmission because ethe behavior only occurs while in drive. I would imagine piston knock would occur when accelerating on park or neutral.
I recently did a ATF and filter change at 207k miles, and extracted ~1.2 gallons (near 5L) of the old fluid after dropping the pan. I refilled with the same amount using the recommended ATF. However, I recently found out that this certain transmission only needs about 3L of fluid.
The last owner (a relative) said he had the ATF changed at 160k miles or so. I also check the fluid levels at operating temp, and they seem fine, but somewhat thick.
Is it possible that I have too much AT fluid?