Our 2013 Kia Sportage 1.7 CRDi has recently developed a problem with gear selection. This is specifically affecting the selection of first gear, whether from neutral or any other gear, and it is also difficult to get out of reverse. It will go in with a bit of force but it feels a bit 'notchy' and I'm worried about damaging the gearbox. I have tested it with the car stopped, and gear selection is smooth for all gears, so this is only a problem with the engine running. I've also checked the clutch fluid reservoir and this is well topped up to just below the max line. Any ideas before I take it to the garage?
Because you can select all other gears smoothly when the engine is running means that the clutch is operating correctly, and the other gears' synchronizers are also OK.
The problem is therefore either within the gearbox (e.g., worn 1st gear synchronizer), or somewhere in the gear-selection mechanism. The gear-selection linkage, of course, has parts both within the gearbox and outside as well, where the linkage connects to the gear shift lever in the cabin.
You may be able to see parts of the linkage. We had an early 80s VW Golf and the linkage passed through the engine compartment. Nylon bushings would wear and could be seen after lifting the hood. I don't know how the linkage on the Kia is arranged, and don't know if you can visually see anything. If you can't see anything, and are not able or interested to begin disassembling to do so, you'll have to take it to a mechanic.