ok guys, i'm going with a Motive 4.10 gear and full install/rebuild kit. for the break in period i've been told to use regular (non-synthetic) 75w90 gear oil, and drive by slowly accelerating/decelerating on a 10 mile trip, then let cool off, repeat, and that's it.
My questions...
1) do i need to use the GM limited slip additive during the break in period, or only after i switch to synthetic oil after 500 miles?
2) how many miles total do i need to drive before they are broken in? a local guy here who owns a shop and has done hundreds of mustangs and many f-bodies and says after the first two short trips, it's ready to go. I've heard 150 miles and 500 miles from other sources...so which is correct?

Thanks very much guys!

 

ttt

 

Motives are damn good gears..id say take it slow a few days to a week...then let er rip

 

i hear that 500 miles is the key. after that put in redline (or whatever you want redline rules) then you can rip them!!

 

I was told not to tow for 500 miles. TOW.. why the hell would I tow... haha

 

btw svt killer, autocross at the sunset station on the 29th! i'll be there! night auto cross kicks ***

 

sweet.. can i get a linky???

 

I did the heat cycle thing and was easy on it for 500 miles and then I tried my best to break it.
They been in for about 40k now and I just took my TA girdle off cause the gasket needed changing and the gears look great, even wear, no metal shavings.

 

my shortest life.. 3 months with one of those months the car was down.... oh and not a single launch on them...

 

Im about to get mine installed, so do I use synthetic for the break in period? And is it necessary to change the fluid after 500 miless??? I was just going to put synthetic with the additive in it right off the bat and leave it there.

 

You can use synthetic without any problems. All the shops I've ever seen that do rearends use the Redline synthetic rearend fluid. Ideally you should change the fluid after the 500 miles breakin period simply to remove the metal shavings that would occur because of the breaking in. It's not 100% neccesary. I never changed mine after my breaking in period and I'm still running strong with 3.73 Strange gears.