Over geared or just time for the lipo to meet the maker

[Gee]

One of my max amps 2s2p 6000's got a little swollen today. I was running the evo today and put in a 30t pinion w/ a 54t spur gear for some speed runs. The temps on the esc (mm w/ ubec) and motor (1515 1y) weren't too high. The couple time I checked the highest reading I got was around 165 on the esc and 140-145 on the motor. Wasn't running it hard just out walking the dogs. So was just doing some speed runs then give it a break then a few more kind of deal. I haven't checked the volts on the two batteries yet. It seemed like the lvc was kicking in and when I went to swap out the batteries that's when I noticed one the battery was a bit swollen up. I checked the temps then and they were about 10-15 lower then the ones above. I put the batteries in a gopher hole under a real big rock with a couple of rocks over. There wasn't anything close (brush) that would catch on fire if it went off. It was close to a park so I tried to hide them a bit. Didn't want someone walking off with them for a couple of reasons. When I made it back to the house I took the car back with an ammo can and got them. I wasn't going to stick the battery pack in my fanny pack for the walk home. It was just one pack. I think it was one of the ones that has been below the cutoff before but brought back to life. The X that marked that pack is gone. It's been almost a year to date that I bought them. So they have had a lot of runs on them. I have also run that gear setup in the past for some speed runs but not hard bashing.

Any thoughts?