I don't think it really matters that much. To be safe follow the manual whatever it says. But when I just finished rebuilding a diesel I'd stick it on the dyno for 3 hours. About the first 15 minutes about half load, mainly just checking for leaks and stuff. Then full load burning the paint off the muffler in about 2 minutes (I guess 1000 degrees exhaust temps help). I would rahter run it harder rather than lighter. I don't think they baby a D10 for 50 hours when it gets delivered to a mine.
OK just went and did a little work, after a scan to PDF, then a convert PDF to Word I have this......from my manual..
A few comments here. It says to not operate the tractor at full speed. Nothing about full load. So operate it a 2000rpm and load it as much as you want? Then "Do not run the engine faster than needed. Huh? So what if I need to. then it says not to start quickly or apply the brakes suddenly. I guess we want to break in the brakes? And my favorite...."this is not only for new tractors but ALL tractors". So it seems like a real CYA for them. Do you void the warranty if you rev it up at 49 hours? Anyway enjoy the reading. Rob BTW I agree with the warm up part. But remember warming up doesn't mean just sitting still. A slow/fast idle out to the work area is a light enough load. Plus I really hope all the enternal engine parts get oil on them in less than 5 minutes. /forums/images/graemlins/blush.gif
WARMING UP
JUMP STARTING
CAUTION
To avoid personal injury: • Be sure to set the parking brake during warm-up.
For five minutes after engine start-up, allow engine to warm up without applying any load, this is to allow oil to reach every engine part. If load should be applied to the engine without this warm-up period, trouble such as seizure, breakage or premature wear may develop.
Break in section....
OPERATING NEW TRACTOR
How a new tractor is handled and maintained determines the life of the tractor, A new tractor just off the factory production line has been, of course, tested, but the various parts are not accustomed to each other, so care should be taken to operate the tractor for the first 50 hours at a slower speed and avoid excessive work or operation until the various parts become "broken-in." The manner in which the tractor is handled during the "breaking-in." period greatly affects the life of your tractor. Therefore, to obtain the maximum performance and the longest life of the tractor, it is very important to properly break-in your tractor. In handling a new tractor, the following precautions should be observed.
| Do not Operate the Tractor at Full Speed for the First 50 Hours.
• Do not start quickly nor apply the brakes suddenly.
• In winter, operate the tractor after fully warming
up the engine.
• Do not run the engine at speeds faster than
necessary.
• On rough roads, slow down to suitable speeds. Do
not operate the tractor at fast speed.
The above precautions are not limited only to new tractors, but to all tractors. But it should be especially observed in the case of new tractors.
■ Changing Lubricating Oil for New Tractors
The lubricating oil is especially important in the case of a new tractor. The various parts are not "broken-in" and are not accustomed to each other; small metal grit may develop during the operation of the tractor; and this may wear out or damage the parts. Therefore, care should be taken to change the lubricating oil a little earlier than would ordinarily be required.
For further details of change interval hours. {See "MAINTENANCE" Section)