While there are plenty of people out there without the slightest interest in electric vehicles, we find it hard not to be at least slightly enticed by the forthcoming Mercedes EQG, an all-electric G-Class.

The G-Class is beloved for its classic boxy shape, as well as its serious off-road credentials. These aspects combined with an all-electric powertrain should make the upcoming EQG one of the most desirable SUVs in the market. As it turns out though, Mercedes-Benz still has some work to do before the EQG is ready for the road.

Popular YouTuber Carspotter Joroen recently had the opportunity to capture a rare glimpse of a camouflage EQG test mule being put through its paces on the Nurburgring. While it was initially shown lapping the circuit without a worry in the world, it later experienced some kind of terminal mechanical issue when it pulled off the track. The loud knocking sound seems like it could be something related to the differential and/or the transmission.

Read: Mercedes EQG To Feature Updated Interior, New Center Stack

Whatever the case may be, the issue forced the EQG to retire from its test regime and wait for assistance.

While many key details remain under wraps, what we do know with certainty is that it will come equipped with not two, not three but four electric motors, one for each wheel. It is unclear how much power it will have but it will probably easily out-muscle the current G 63. It will also be able to perform tank-style ‘G-Turns.’

This particular prototype was spotted with a full-size spare wheel and tire mounted to the tailgate behind a cover, just like the combustion-powered G-Class. However, a different prototype spied testing just a few days ago ditched this spare wheel in favor of a small, square box with rounded edges that apparently houses the charging cable. It’s possible that Mercedes-Benz will offer customers the choice between a tailgate-mounted spare or this charging box.