Lipperts warrenty on the legs is "ONE" year their frame is longer. The legs are made by Venture Mfg. Co., 3636 Dayton Park Dr., Dayton, OH 45414, Tel: 937-233-8792. The slipping noise could be the gears stripping or the slip clutch in the reduction gears. As stated you can inspect the gears at the top of the landing legs by lifting the flat cover. There will be a lot of grease there and you want to replace it if removed. Remove the grease and feel the edge of the two ninety degree gears. If they are pitted as in my pictures then you need to replace them with the kit.
I took pictures of the repair and damage.
I hope this helps.
Let us know what you fined.
Cheers,