you will get varying answers. some say drive it like you intend to so the engine wears in as to how you will use it. some say baby it for 1k+ miles. i just read something that said with todays modern metals, bearing clearances, and oils its not necessary to break in an engine. but it did recommend not do to any WOT runs for a few miles.
really, id say go for it. you bought a truck so use it as such.
Most engines these days come pre-run at the factory, so they get well into the break-in period. Even then, a lot of the manuals that I have thumbed through suggest babying it for 500 miles. You can burn up those miles with just a couple of short trips around town for a week or so and you'll be set.
Yeah, like Steve said, the 500 mile break-in is what GM typically recommends before doing anything too crazy. As it does in my users guide. In fact, here is exactly what it says on page 2-16.
New Vehicle Break-In
Notice: Your vehicle does not need an elaborate
break-in. But it will perform better in the long run if
you follow these guidelines:
• Keep your speed at 55 mph (88 km/h) or less for
the first 500 miles (805 km).
• Do not drive at any one constant speed, fast or
slow, for the first 500 miles (805 km). Do not
make full-throttle starts. Avoid downshifting to
brake, or slow, the vehicle.
• Avoid making hard stops for the first 200 miles
(322 km) or so. During this time your new brake
linings are not yet broken in. Hard stops with new
linings can mean premature wear and earlier
replacement. Follow this breaking-in guideline
every time you get new brake linings.
• Do not tow a trailer during break-in. See Towing a
Trailer on page 4-51 for the trailer towing
capabilities of your vehicle and more
Following break-in, engine speed and load can be
It's not the engine that needs break-in. As posted above, the engine is run at the factory, and the transmission is just a bunch of clutches and steals...it's broke in when it's broke. The part of concern is the Rear End. The tight ring and pinion mesh required some break in time. This tight fit generates a lot of heat. The additional heat caused by high speed/load can overwhelm it. Do yourself a favor, Drive it for 1000 Miles, nicely. Then go get you some high quality gear lube of the correct weight, and change out fluid in the diff, or diff's if it's 4 wheel drive. Gm says 100K Thats bull. Any axle manufacturer will tel you that break in fluid NEEDS TO COME OUT! If you change the fluid, and after seeing what comes out believe i was wrong. I'll pay for it. Trust me, you'll be happy you did. -Murph
iif you plan to make this your tow vehicle get the larger axle covers to allow more oil to keep all cool. i say 500-1000 miles is what i give most new major car parts before working them out alot....mike
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