I just bought a second hand commuter bike with Sram G8 hub gearing. The seller told me something is wrong with the shifting but he wouldn’t bother trying to fix it. So I just thought I’ll give it a shot. Problem is, that it does not shift into the three highest (lightest) gears (gear 1-3). From 4-8 it shift perfectly well, when I go beyond 4 to 3 the gear gets really low (more resistance than in gear

Any idea what the problem could be? I figured that the shifting seems vice versa than on a normal groupset (I’m normally on road bikes) which means you shift into the lower gear with cable pull.
Thanks in advance for you help!
Kind regards!