The dryer squakes very bad. I took it apart but can't find which wheel is causing the problem

Grease all bearings with white lithium grease and you should be able to fix it. Sometimes you have to replace the support rollers, which are very cheap, to get rid of the noise. Make sure to check belt tensioner as it will get worn and make noise. You can get some oil and spray each roller until noise goes away. Then after finding bad roller or belt tensioner take dryer apart and replace or grease the part. I do not know if your model has a center drum bearing, but it has to have lithium grease every year when it's cleaned.