I don't think I did take mine out on the road for the first 50 hours anyway. And boy does she fly. My brother has an HST, slightly smaller tractor anyway, but at least 25% slower than my L3400.
I had a L3400 GREAT tractor and it sounded the same as you described in 4th gear. Now have a L4400 and it sounded not quite as loud for the first 250 or so hours but now it has 305 hrs on it and its now not near as loud I wouldnt worry about it.
