Spin cycle will only spin at slow speed sometimes

Replace the motor your centrifical switch in the motor is bad

check under lip of washer or around outside of tub. A garment may be in the void between tub and basket. It won't always slow down spin cycle as it may roll around when spin cycle is on but occasionally it will ball up and jam between the basket and tub thus decreasing the spin speed. Socks are a common problem and if you are sometimes whiffing a foul water smell that is the article of wet clothing that has remained wet for some time.

does it pump out all the water when it spins the first time? when they spin slow sometimes the pump is not pumping out all the water causing it to spin slow.

is the drain pump ok .ie if the water does not get out in the proper time the mach will think it is still full and will not speed up

It's possible that the tub didn't drain properly in the allotted time and the remaining water is slowing your drum from coming to maximum extraction speed.

If you timer switch "skips" the spin cycle (passes through it faster than normal) then it is probably your timer switch.

Or it could be your transmission. The transmission is a two speed unit and the wash cycle is the slow speed and the spin cycle is the fast speed. So if the problem is only the spin cycle then it could be transmission problems. BUT since the transmission is normally a sealed unit on the newer machines you will have to replace the entire transmission instead of just the high speed gear.

The transmission in this machine is worn and is not shifting correctly. Understand that after the aggitate cycle, this machine should go into drain cycle without spinning and it should drain for about 1 minute. Then it should kick into spin cycle after it has emptied all the water. What is happening is it is (like skipping) the drain cycle and going directly into spin with water still in it,,, so the spin is slow as it is trying to empty and spin at the same time,,, thus the clothes do not spin out correctly,,, when you reset the spin, you actually spin all the water out the second time around.

we can eliminate the motor and the switch since that part is working. sound like your timer might be faulty, timer make everything work in persistence cycles, if its goes bad sometime it tend to jump/skip cycles.

(I know this is an old question, but its probably a common question for new owners - including me a couple of weeks ago...)

Power the unit back on, press the spin speed button and it will select the "drain and spin" cycle. Pressing the spin speed button again will select different spin speeds as well as just "drain".

Something you might try instead of medium spin speed is to turn on "SpinSense". To turn this on (and off), press and hold the "Stain Cycle" button for 3 seconds while any wash program is in process.

What SpinSense does is measure the imbalance by doing a very slow spin before cranking the spin speed up (and measuring how constant the very low spin speed is). If the balance is out too much, it will stop, let the clothes drop, and then try another slow spin. It will try this over and over many times until the balance is decent. Then it will let it rip. It makes a huge difference, but it can spend a lot of time getting a good balance some times.

SpinSense also seems to be able to detect if the machine is shaking terribly, shut the spin down and try again.

Our LG 2688 is on our 1st floor (wooden floor). Without SpinSense, the vibration was terrible and with it, it is tolerable.

For some reason we typically get less vibration with "Extra High" spin speed compared to "High" so that is another option you might try.

yes it could be normal if the balance control senses that the load is uneven however the same problem could be caused by a blocked filter or blocked sump hose.