This is not a typical problem at all. Call the installers back. They are in warranty.

Is there some problem with the Liftmaster 3280, since both openers seem to have this noise problem? Is it a bad run in the manufacturing affecting the gearing? I just get so suspicious that there is a rev change that the manufacturer does, and then the consumer has all the hassle of getting things taken care of even though they are on warranty.

Well my last sentence in that post went haywire. What I meant to say was It will possibly help if you can be at the openers when you call and have your model numbers available.

I talked directly to Technical Support at Liftmaster, and they evidently have a problem with a run of belts that they currently do not understand completely. The belt does a half turn. They will replace the belts right now, but they want the belts making the half turn returned to them so they can examine them. There should be no squeak at all. Temporarily they suggest lubricating the gear system with lithium grease.

I know this thread is old, but I wanted to post some info. I had the same squeak, but one door was fine and other squeaked. I called the number listed above. The guy was very nice and did some over-the-phone trouble-shooting with me. He said the belt should be greased at the sprocket and the pulley ends. I was skeptical, because it seemed strange to grease a belt, but he assured me that it should've been greased upon installation. He also indicated the use of white lithium. Living in Wisconsin, I avoid white lithium, because it works more like glue than grease in the cold. I used Super Lube and the opener is now silent, like its partner!

Be wary when the installation company has you doing the troubleshooting / temp repairs. The 3280 has a lifetime warranty on the motor and belt drive. If the installer is not willing to come back out and fix it then lookup another liftmaster dealer in your area and ask them if they will fix it under warranty. Your warranty is good through any liftmaster dealer