just wondering how much heat will build on a new rearend install driven at highway speeds or 30mins+

after drives like that it seems to be hot coffee cup hot. like the cup from tims is too hot to hold on to.

shorter drives it has been hot tub hot, right after a autocross runs it gets about that hot.

it basically has less then 100km on it. will it start running cooler? or was the pinion preload too much?

there is no gear whine and the backlash was .010

it was a 4.10 install in a 05 mustang gt..i tell ya... worth paying someone else to do, never again.

 

As long as it was broken in and you have no issues don't worry. For gear break in you should drive about 20 minutes and then let it cool for about 20-30 minutes, and do that 3 times. But in operation they get hot, moving parts make heat. The longer and harder you drive, the hotter the rear end is going to get. On cold mornings after I've been driving for a while and I go through a puddle, water that splashes on the diff turns to a big old steam cloud

 

that is normal, not only are you getting heat from the rear end itself, you get heat from the exhaust and engine blowing onto it as well. as long as you aren't experiencing whine or problems I would say you are fine.

 

i dunno... the stock rearend got like kiddie pool warm in a side by side distance/speed drive.. (buddy has a '05 as well)