Not familiar with Newmar but on our Thor, you can retime the slides by opening the slides about 10 inches then close them making sure to hold down on the switch for about 5 seconds longer after they have closed. Then open them all the way out, again holding down on the switch for 5 seconds afterward. Do this about 5 times - should be back in time.
Another issue we had a while back. The rubber on the slide actually rolled under and I couldn't get the slide to close or extend more than 6". I took the cover off on the inside and slid a small scrapper down the inside to pull the rubber back out.
Hope this helps;
US Army Retired - loving it in our Challenger 37TB.