To break in a new differential?

 

When I had my Auburn and 4.56's put in, the guy told me not to tow anything for about 2 weeks, other than that, it was good to go.

 

been reading up on that myself and the most i've seen is 500 mi !!!!

basically you need to put in enough time to let the gears set/lap themselves and go a few easy heat/cool cycles.

after that change fluids and then go do what you want.

 

yeah 500 miles is the safe number.

 

500. That diff cover get HOT!!! I just had my rear end done 2 months ago and I broke it in for about 300 miles before driving normally. Went to the drag strip right around 500 miles as well. I changed the fluid right before that drag strip pass and that fluid was NASTY it was black and smelled like ****. I did another fluid change a few days ago back there at 1000 miles just to be on the safe side. I reccomend doing that for anyone who has had their rear end done. 500 miles, 1000 miles then the normal 15,000 miles or something. What did you have done back there? What kind of gears as well?

 

Factory rear blew up, it was covered under warranty so they replaced it with a 3.55 posi. Good highway gears and definantly are quick too. So nice paying 108 dollars and looking under my truck and seeing a completely new rear end assembly haha.

 

So you like them so far huh?Were they anupgrade? I have them and hate it. Good highway, yes, but long grades and even hilly back roads really suck. Especially if you have something heavy in the bed. Superchips makes things a little better, but I'm still changing out to 4.10. What year is your truck? Did you have the computer flashed for the tranny or whatever?

 

Mines an 03' got the superchip too. she hauls...but then again I dont pull a trailer all the time. Most of the time I have the tonneau cover on and am just cruisin around. At most I'll carry some lumber or my dirtbike around. But for hauling stuff all the time I can see the 3.55 being a pain. I wouldn't go all out to 4.10's tho, your highway mileage is going to go down the drain. you should be well off with the 3.90

 

Mine's an 03 too. Diff didn't blow up on me yet, but I haul stuff often and really want the gears. Maybe after a few fill ups at the gas station you might be right about going 3.90. But a lot of guys here swear by there 4.56's, so I thought go conservative and get the 4.10. Oh well, we'll see. Glad to see that you only paid 108 for a new diff! Now lets see some more vids of your new diff tearing up the backroads

 

I have 4.56's and my highway mileage dropped maybe 1/2MPG @ 75mph, but around town increased by about 3MPG, and performance is unbelievable! I also had the Auburn posi installed and it is a great unit as well.. So to me it is well worth it.. Towing is a lot easier too, so if you do any heavy hauling, the gears are a must.