old and rusty

...and appreciate the input Tug, I'll try popping in one my lipo's and see if it helps

Update on the granite 4x4...upon pulling the gearbox back out found a small pebble behind one end of the assembly throwing out of alignment slightly, didn't think it was enough to cause binding in the drive train, but after going back to the 14t, and putting it back in the truck noticed that it did seem to turn a bit easier....that wasn't the problem. Still had the slowing down, then speeding up. When checking the motor temp. it was only slightly more than luke warm to the touch, and capacitors not warm at all (is that normal?) It's been suggested by some that the problem is the cheap TSKY ESC, and that you get what you pay for.

had recently installed a steel spur gear/ slipper clutch on a Arrma granite 4x4. it came stock with a 14 tooth 48 pitch pinion for the brushed motor. (prior to this, it had been upgraded to a BL 3100kv motor, and a TSKY 120amp Hobbywing clone ESC and never had any problems) In the process of replacing the spur gear, one of the wires for the two caps was knocked off of the ESC and was soldered back on. the spur gear replacement came with 3 pinions of 17, 19, and 21 teeth. Since they had come as a set, thought it would be best to use one of those (the 17t). After buttoning it all back up, and taking it for a test run it still accelerated, well and had decent top end, when suddenly (while still holding full throttle) it cut to about 1/4 speed, which it would do for approx. 20 seconds, then resume normal throttle. Forgot to mention he's running a 6 cell NiMH 3800 battery (if that makes any difference). My question is does it sound like i've just overgeared it, or that I could have problems with the capacitors? Will put the 14t back in to see if it helps, but if it's the caps, don't want to make things worse by running it. Any input would be greatly appreciated...thanks (sorry about the wordiness of the question0