Break in Period w/4.10s

helty

some Ukrainian's enjoying a handjob via my credit
Mar 30, 2005
1,461
1
39
Baltimore, MD
Having FRPP's installed Saturday morning, and Saturday night some of us are going to the track. It would be my first time and I really want to run, just dont know if I should with the gears being new. Is there a recommended break in period? If so is it a # of miles or time? Cause I have no problem putting a hundred miles or so on it in one day. Would you recommend sitting the night out or running with the new gears? OR is the whole break-in period just a myth? :shrug: Thanks.
 
  • Sponsors (?)


I've had 2 different answers from 2 reputable installers. First one said 500 miles to brake them in, second said until the end of the driveway then punch it. So i don't know...i've done it both ways. As long as the install is done right i guess you don't need a brake in period.
 
actually i got mine with 22k on the odometer, but i know what you're saying. i think i can manage to put some miles on them while taking it easy, and make sure every thing's ok with them before getting on it. i think*
 
I would drive it about 8 miles to wear the paint off the gears and make sure all of your bearings are all lubed. Drive it side to side somewhat to splash the oil everywhere. then nail it as much as you want. But you CAN get on its as soon as you take it off of the jack stands if you want to. The above is what i did and have had 0 problems.
 
at school, ive been taught 500 miles just to be safe. i gave mine 500 miles and i have zero problems now. im not really sure what kind of metal the gears are made of, and if theyre forged or not, but i would def take it easy on them for AT LEAST 200 miles. def do the cycling of heat/cool at least 3 times. new metal tends to expand and contract more than metal thats been broken and hardened in already. the same principle should be applied to a new car. pu$$yfoot it for the first 500 miles, then let 'er rip. my personal stang i give longer just b/c im very anal. if it were my personal stang, i wouldnt race it that night. i'd give it a week and go next saturday. this is also what i would suggest to my customers, but its up to you.
 
Probably depends on if you can afford to have it fixed if you break it.

Personally, I would think if the gears were installed properly, there shouldn't be a break in period. Any wear to the gears is probably normal, and I wouldn't think spinning faster or slower would affect this, but that's why I don't work at a differential shop.

Gear wise, I got mine for free, and they are being installed for free, so if something breaks, aw shucks.. I'll bring it right back and have them fix it, for free.
 
im getting the FRPP 4.10s for $100 and install for $50 by a Ford mechanic. He's done it countless times on his own drag-car, so he knows what he's doing. He'll also stand by his work, as long as its something I dont F up by driving like an ass. I dont plan on launching by revving and dropping the clutch or anything, just feathering the clutch. I'll probably drive the wheels off it all day and try to rack up a hundred miles or so. If all goes well maybe* I'll hit the track. Thanks for the replies.
 
helty said:
He'll also stand by his work, as long as its something I dont F up by driving like an ass. I dont plan on launching by revving and dropping the clutch or anything, just feathering the clutch.
no worries, ive NEVER heard of anyone breaking a ring or pinion gear. the metal has been hardened like a mother. your diff will go out/slip before you break a gear.....like mine is:(