BR slide moves OK but every 4-5 inches, it.......

[robertsondan]

2014 KEYSTONE 34' MONTANA HIGH COUNTRY 318RE

The BR slide moves in and out ok (for now) but every 4-5 inches of travel, it hiccups and seems to stall for a split second and the keeps going. Each time it stalls, you can hear the motor (?) change speed. My other two slides (kitchen and dining area) operate perfectly. From outside the coach I looked at the nylon rollers that support the BR slide thinking there might be a flat spot on one of them, but they all look perfectly fine.

Any suggestions to diagnosis this issue?

Thanks
Dan