Hi Len, and welcome to the greatest RV forum on the internet!
I had '99 Chieftain for 5 years and my nephew now owns it. I had the 34Y model with the kitchen slide too. I did make adjustment to it but that was many years ago & I don't remember any details.
Does the slide fit square on the outside against the wall of the coach?
If yes, then you want to raise the whole slide at that end that's rubbing the floor.
If no, and it's tight at the top but out a tad at the bottom, then you want to raise just the inside end of the slide arm. That's probably the access point your looking for. With the slide out, you should be able to see it from underneath the coach. If not, you should find an access plate that you can unscrew to see the adjustments. This is where my memory is fuzzy. You may find the access plate inside the opposing storage compartment.
There is definitely an access panel to make the adjustment(s). They use that butyl rubber seal on these access panels and it sticks like crazy. So once the screws are out, just pry with a screwdriver and slowly pull the sticky stuff apart.
Good luck & welcome to iRV2,
Bill (Dune'r) & Helen
Last of the Chieftains, 2004 39T, W22, Banks Headers, Koni's, Safe-T-Plus, SMI brake
2013 Lincoln MKZ Hybrid towed 4-down