Aisin AR5

Aisin's five-speed manual for General Motors — in the Hummer H3, the Pontiac Solstice and the Saturn Sky.

It is not the AX-15 and it is not derived from the A340, both of which this catalogue briefly claimed. The AX-15 is Aisin's Jeep gearbox and the A340 family are automatics; the AR5 shares a manufacturer with them and nothing else. The confusion is easy to make because Aisin's naming gives no clue which is which.

It is a light-duty gearbox in vehicles that ask a lot of it. The H3 in particular is heavy and geared low, and the failure is the fifth-gear synchro and the shift fork — a grind into fifth alone, or fifth refusing to stay engaged under load. A gearbox that jumps out of one specific gear is a fork or a worn hub, not general wear, and that is repairable without touching the rest.

Shift quality complaints are usually the linkage. The lever bushings and the shifter's own base wear, producing a change that is long and imprecise and reads as a worn gearbox.