OV9

My son’s HPI Blitz appears to have done something to it’s gearbox and/or diff. The motor is just spinning with no drive. Normally, if you turn the wheels by hand, the wheels turn in opposite directions (presumably open diff) but now they’re both turning together, but they turn freely with no sign of any binding.

Any ideas what it’s likely to be? I’ve done a quick Google but can’t find anything similar happening to anyone else.

It’s particularly annoying because I only bought a new battery pack for it yesterday after him not being able to use it for a year after the last pack died (kept forgetting to order one). He’s had 20 mins with it and now it’s knackered again

Has the drive gear come loose from the motor shaft? Happened on my Optima Mid on a few occasions.

Hope so, easier than fixing a broken part. I’ll have to strip it down. Lots of tiny bits to lose.

The motor spinning with no noise other than the motor itself would point to the gear coming loose on the motor shaft.

Other grinding, clicking or roughness would usually point to a broken gear or diff.

Shouldn't take much work to get the motor off and open the gearbox for a look.

integrale_evo wrote: Fri Feb 22, 2019 6:38 pm The motor spinning with no noise other than the motor itself would point to the gear coming loose on the motor shaft.

Other grinding, clicking or roughness would usually point to a broken gear or diff.

Shouldn't take much work to get the motor off and open the gearbox for a look.

Looks like 2 x teeny tiny cap head screws to get the cover off.

Sorted. Grub screw had backed out of the gear on the motor shaft and got itself stuck behind the spur gear. All fixed. Ta. I was expecting a difficult job needing better eyesight than I have.

NotoriousREV wrote: Fri Feb 22, 2019 7:13 pm Sorted. Grub screw had backed out of the gear on the motor shaft and got itself stuck behind the spur gear. All fixed. Ta. I was expecting a difficult job needing better eyesight than I have.

Locktite it or it’ll come loose again.