5150_GT

Putting my FRPP 3.73's, LCA, CMDP and Brenspeed 91 Tune on Friday. Is there a break in time recommended for the gears? I am very eager to get back to the track in Sacramento.

Ran a 13.30 with my current set up of 3.31's, UDP, Steeda CAI, canned 91 tune from SCT2, and TB spacer.

Want to see what I get now!

moosestang

500 miles is the generally accepted time frame, but my installer said 3 heat cycles and I should be good to go. I still waited 500 miles before I hammered it.

onederful100

i broke mine in for 500 miles driving at various speeds, but no hard launches, changed the gear oil after the 500 miles. some say there's no need to break in, but i like to be on the safe side.

Diabolical!

There is no need to break in rear gears. By the time you drive home from the installers, the wear pattern is set and by the time they cool down after that first drive, they are broken in. Install today, race tomorrow. No problem.

Norm Peterson

Risky, very risky.

If it's long gear life that you're after (vs being under pressure to make tomorrow night's race), break them in conservatively. The basic wear patterns may be set within a few miles, but the final microscopic-level tooth profiles are not. The gears and the lube will run somewhat hot until the tooth profiles are worn in to each other.

Drive easy and at varying speeds for about 50 miles at 50 mph and under. No hard running or Interstate driving at all. When you get done, I'll guarantee that the diff cover will be too hot to hold your hand on. Let it cool overnight, as it takes a long time for all the heat in the internal bits to dissipate. Repeat the 50/50. The diff cover should not be as hot after the second time. Still to hot to hold your hand on? Let it cool overnight and do the 50/50 drive again.

Heat is caused by a sort of "final polishing" under heavy pressure. Overheating the gears can affect the temper and lead to their shorter life (never mind not being particularly good for the lube either). As good as gears are (some, anyway), they are subject to manufacturing tolerances just like anything else. Meaning that you could get a really good set that actually does break in in less than 50 miles - or you might get a set that's not so good and takes 3 or more drives. There simply isn't any way to tell where your particular gear set falls in this 'tolerance' respect until you're actually breaking it in.

Yes, I also break my new cars in with this in mind.


Norm

ensign_lee

^^
Good advice

---
on another topic, wow, you're getting a lot of stuff done at once. That's gonna be a completely different stang when she comes back!

GidyupGo

Not what these folks say.
http://www.4x4now.com/gt0999.htm

SaddleUp

I don't plan on taking it easy on my new gears....once I get the baby's in...

MY girl is gonna be soooooo good when she's done....new gears, new wheels, new tires~!!!!

She'll be ready for a trip to Lone Star~!

Diabolical!

The gears in those pictures are a good example of what happens whe the backlash is drastically off on a set of new gears. It's always been my experience that if gears are installed right, they are good to go.