I've replaced the cracked gears, and left the others, and a week later had to replace the ones that weren't cracked when they cracked later.Turns out it has the QSi DCC sound unit factory installed by P2K. SO no new speaker since they are round. have to get a round one. The split gears are replaced. did all four axles. Interesting it was just the two inside axle next to the fuel tank that split on both trucks not all four.
Ditto that here.I've replaced the cracked gears, and left the others, and a week later had to replace the ones that weren't cracked when they cracked later.