So yesterday without much warning the Infiniti-branded 48-month battery went south. Weak crank upon re-start after first morning drive of about 5 miles to an appointment. Midday went to run an errand and it would not start, with rapid clicking and flashing of dash lights showing weak battery. The battery was 23 months old; battery warranty was 100% replacement up to 24 months

I have Infiniti Elite warranty, so I called and had it towed to dealer. Turns out the battery was bad and starting to leak acid. So it cost me nothing to get the battery replaced and I got a free car wash and vac to boot. All in 2.5 hours from start of problem to pickup.

So here's the odd thing. I was working my way up to post about a troubling sound the transmission was making. 2006 AWD sedanX. When slowing to a stop, as the transmission was downshifting, you could hear a pretty pronounced "growl" or "moan" in a low-pitched frequency as you rolled to a stop...say from about 25 mph down. The pitch would change in synchronization with the slowing speed of the car, getting lower pitched as slowed, then when the downshift came, pitch back up and then going down as you slowed further.

Lo and behold, at the first stop sign after picking up the car, the sound was completely gone. And has stayed gone since.

I seem to recall reading a couple of threads where there was mention that having a weak battery can make all sorts of weird things happen with the car that you wouldn't think to diagnose as a battery problem. Is this one of those instances? I'll also say that the idle seems to be smoother. Is some of this due to a ECU reset brought about by the battery being disconnected during the replacement process?

Just wondering....