Helical cut hub gears?

I have an 86 m998. I have been looking at swapping to the helical cut hub gears when im rebuilding hubs. Has anyone done the swap to the helical cut gears? Is the only change the input and output gears themselves or would it require more like ctis spindles or something more?

I'd be interested in finding this out, too, but I don't want to take the time to flip between part manuals to spot all the P/N differences. Anybody here actually done it?

You don’t want the helical cut gears IMO, they are not as strong as the straight cut, only advantage is they are quieter.
the cost of the gears bears no fruit in the end...

Did AM General use these and if so what s/n is the change?

Retiredwarhorses said:

You don’t want the helical cut gears IMO, they are not as strong as the straight cut, only advantage is they are quieter.
the cost of the gears bears no fruit in the end...

Click to expand...

Helical cut gears have more mesh area and therefore are typically stronger. At least thats what i understand

H1 alpha models had them in 2006.

What maximum speed are each type of gear designed for?

The helicals are stronger and quieter at speed, but they also introduce a side load. I don't know what all they were used in, the only one I heard of was the H1 Alpha, so if that's the case you'd be looking at a limited production part made specifically for the civilian side of things. If they were used in other models than the Alpha they might not be so bad to find, but, as with most things, if it isn't broke then don't fix it.

I found a thread over at the Hummer forums, one guy said he was involved with the racing side of things, the spur gears did just fine at 110+ mph off road.
Also found several reports that the reason for the helical gears had to do with noise and the rocking motion after you brake to a stop, due to the inboard brakes and clearance in the gears. Unless a slight reduction in noise and a little bit reduction in rocking after braking to a stop are the end goals, it's probably just not worth it.
https://www.hummerforums.com/forum/hummer-h1-16/h1-geared-hubs-29066/

I just got a private message correcting me, it appears the REV HMMWVs above serial 300000 got the helical gears, so will be a little more common.

That being said, I don't know how much of those parts have hit the civilian/surplus market, so still going to be very rare compared to the standard gears we're all used to.

To get back on topic, yours is an 86, so unless it's already been changed out you're likely to have either the 7.7 or 10k drive shafts, the helical cut gears use the 12k driveshafts, so they would need changed over as well.

For either type of gear cut, the maximum speed is 767 MPH at sea level... THEN wait for the boom BOOM !!

Just messing with Ya TOBASH, CAMO