I installed Caltrac Monoleafs last summer and love them. This weekend I noticed that they are starting to squeak way too much. I sprayed silicone in between the two where they over-lap but it didn't work. Any suggestions?

Do you have poly eye bushings? If so this may be the cause.

I do have poly eye bushing, however, when I lay under it and someone pushes the bumper up and down, it sounds like the noise is coming from the area where the leafs overlap. I sprayed silicone between the leafs but it didn't solve it.

I guess I'm confused. You refer to a mono leaf but say the leaf(s) overlap?? Monoleaf usually refers to a single spring.

Caltrac Monoleaf springs are two leaves that overlap by about 10 inches in the middle.

More then likely its the poly bushings that have worked the grease out of them.