40+MPH/Quiet 2016+ Gear Swap

Working with Rodney @Old_Houseboater on a new project. He posted a little about it a couple months back but here is an update teaser.

Increase speed of stock 2016+ GEM to 40+ MPH while maintaining reasonable range.
Reduce gearbox noise - factory gearboxes are really (really) loud.

Below are some pictures of our test mule.
This is a 2016 GEM, What @Old_Houseboater has built is a new gearbox (10:35) and half-shafts that will replace the factory gearbox. The only modification needed is to drill four new holes to bolt the gearbox down and swap out the half-shafts. The new gearbox mounting holes are slightly wider than factory. You use the factory mounting brackets on the new gearbox. This simple swap will take a factory GEM from 25MPH to almost 42MPH with stock wheels and tires.

These gears are quiet It is hard to tell in the video below but high speed is normal gear noise as expected from a classic GEM and regen is almost silent.
We still have some work to do on the half-shafts to get the length perfect but we are not far off.
I will report back exact speeds once I can get a decent day for testing.

@Old_Houseboater - anything to add?

Video of a short test run:


A big Thank You to Mike for the help in bringing this project to it’s present state. He has been putting this together and testing in a secret unheated garage in Siberia. Did you notice the little bitty motor he has on his machine? Awesome!!!


AKA Old Houseboater

It has been a long cold winter, looking to turn the corner soon !!!
I think is is going to be a great easy kit for GEM owners to really get the true potential out of their cars.

Motor, what motor?

Neat. I don’t see myself in a GEM Cube anytime soon, but that you guys were finally able to break past all the restrictions on the new ones is super cool.

That put a ■■■■ eating grin on my face just watching this!!! Holy-moly!!!
That thing is nuts!

I had no idea this was a division of GEM/Skunkworks?
I applaud all of the out-of-the-box thinking that goes on here.

I sent a catalog and drawing of how cv joints are spec-ed by dimensions. Is either shaft the correct length, so as to only need one new cv joint?
I have not yet found a place to by solid shafts only.

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I will get that information this weekend - The biggest difference I see is the gear end of the shaft on the new cv joint is about 2" shorter than the cv on the factory shaft.

Different tooth count


Gear box end has different spline. Looking for same spline as wheel end. Would appreciate a copy of catalog.



Worldparts CV Axles_Quick Specs_May-2015.xlsx (goworldparts.com)


Dave emailed it to us a few days ago, I just sent it to you again.
I plan to pull the shafts apart tonight and get measurements before the Arctic wind rolls in and it -10 out.
I will email you the data.

I think you can have the shafts made if you source the cv joints.

Dave it would be interesting to try a Mount system that uses a Early stock gems mount system and NOT have to weld the mounts on the transmission like with Rodney’s kit

Good idea. Ill send you a transmission.

I think what point here is that the mount system would need fabicated. I am speaking for Grant so (sorry Grant) but I don’t know if he has the tools required to do so. ?

The … Shafer/Dana 10.35 Transmission kit for 2016 up will be available March 1.

The QUIET alternative, with the right ratio to give 40MPH on your 2016 up GEM, without drastic range reduction.

Drill 4 holes, and your installed.



How fast do you anticipate a Gem E6 will go? What is the price?

Not suitable for E6. This package is for 2016 up.

They make E6’s in 2016+ -

I did hear I have to be careful with gear swap on my 2017 E6, supposedly it is heavier and the weight impacts the gear.