Cargo rack problems

[Canonman]

Our Cougar is equipped with the Lippert Cargo/Bike Rack P/N 126890. They call it a "Sliding Bike Rack". I wanted to cut this pretty much worthless thing off and have a standard 2" receiver welded on in it's place, mostly to carry our two bikes. DW wanted to keep the rack so I put together a rig so we could attach our Thule bike rack to the cargo carrier. It worked well on our trip to Grand Canyon so I guess we'll keep the carrier. Here's the problem. The rack is super hard to slide in and out. Always was, even before the mod. It's a wiggle jiggle huff and puff dance that I'm hoping someone out there has found a solution to.
Any ideas would be most appreciated!
Thanks