Flying to get my '05 HD then driving 500 miles home for the break in run, in a single stretch. Will vary speeds and rpm as required. I've read in an '05 manual they recommend a 500 mile towing break-in at nothing over 50mph as well. I'll be doing the 500 mile pull back north a week after I bring the truck home pulling a 22' camp trailer and loaded truck. We usually make the trip from the driveway to camp in about 11 hours with the old 454 at 70-75mph. 50mph is going to probably require an overnight stay in the middle.. not a big deal but would rather not.

Is there a big risk of damage if I tow at 70 or so instead of the 50mph recommended? The answer is to do what I feel ok with I suppose. Any experiences out there?

Thanks. Great bunch here BTW.

NOTNSUV, you are going to think ol JJ is following you around on the DP. ):h You will get mixed reads on the DP about break-in while towing. Best to do a search on the DP to gather intel. IIRC there was a post from a guy that worked on developing the Eaton axle where he spoke about breaking in the axle/gears. :confused:

I'm not a techie type so I don't know the appropriate lingo to use. :o: Essentially what was posted was when you put a heavy load on the truck the gears are meshing together differently than when there isn't a heavy load on them. ;) For the initial towing conditions the recommendation was to limit your speed to allow the gears to break-in properly while under towing conditions.

That's about as good as I can explain it. Maybe one of the techs can add the more technical stuff. Later. JJ :)

I buy my trucks new and tow heavy right off the bat. Most of my trucks see 150,000 miles + before we trade them in. Never had any problems I could relate to improper break-in.