My new LS XR4155 did the regeneration thing for the first time today at 28 hours, first thing I noticed was the indicator lights on the dash lighted up, couple minutes later a bunch of whitish smoke or steam Looking stuff blowing out in front for a minute or two, the indicator lights stayed on for probably about 10-15 minutes and then everything seemed to go back to normal. This was a new experience for me but the dealer had told me a little about it when he delivered the tractor, he said he gets lots of phone calls from new owners the first time it happens. Thankfully I had also done some reading about it after what he told me. So far my new tractor has never been worked very hard at all.