I was ready to reply with info on adjusting the load sensor on the slide drive controller ; until I re-read your post and saw " chain skips a tooth ".
I haven't seen any Newmar posts discussing chain driven slides so I'll wait for other members to respond and perhaps learn something today.
Have you seen the other posts about Newmar slide motor mounting bolts working loose ?
99DSDP 3884, Freightliner, XC, CAT 3126B, 300 HP /ALLISON 3060
2000 Caravan toad, Remco & Blue Ox.