Most likely on the gear shift under the handle on the righthand side.
Head was redrilled
Our 1.6L Nubira had a timing gear fail. The mechanic at the time continued to turn the engine over in the attempt to start it which bent all 16 valves in the head. The repair cost was over $1700.00 & that was back in 2006. You might be better to go & pull a head from another Nubira from a reputable wreckers.
How do you remove the gear shift knob on a 2000 Daewoo Lanos?
Unscrew it from the shaft
your shift lever bushings are bad, easy fix.
Check the hydraulic fluid reservoir for the clutch master, it may be low/empty. Filling it may get you by for awhile but you probably have a leak in the system and it should be fixed.
The speed sensor is located on the top of a manual transmission gearbox, it would fit into the top of the gearbox and kept in place by a single bolt. It will have a detachable plug that will have 2 or 3 wires that plugs into the speed sensor in the gear box.
Probably worn out shifter bushings
piston 4 is the nearest to transmition gear
replace bushings on shift rod at both ends under shifter and at the transmission easy project i recommend polyurethane bushings available at most parts stores remove old measure holes carefully then have the parts guy find bushings to fit usually alot cheaper than a kit