One of these days I'm going to go tho the barber and he's going to tell me that after my haircut I'll need to break it in for the first week, lather, rinse, but don't repeat.

 

I think the break in period for gears, is so it gets a nice pattern worn in and you can listen for noises, just jumping in and romping on it is pretty dumb, I would never advise it nor would a respected mechanic, most mustang "backyard mechanics" think as long a you get ford gears you can reuse the shims and not measure anything also

I waited like 300 miles or so before I launched it or shifted really hard, you can WOT just don't slam gears or launch it really hard

 

Cool, all good info. If all goes as planned I should be getting 410s in the nearer future.

 

Um.. >>>Ford mechanic here <<<

Still think gear break in is unnecessary... I've done several gear swaps. I never "break in" them.
I've done gears on a 11 second car that right after the gear swap he put the car on a trailer and headed to the track and launched the **** out of it... guess what. That was a year ago. He has made no telling how many drag passes with no problems with the rear diff.

 

Ridiculous

 

Anyone can be a mechanic without any schooling, are you ASE certified? And what would some one gain by telling you to take it easy for a few hundred miles?

 

Ford mechanic doesn't mean good mechanic FYI, for ever good one there is probably 1,000 bad ones.

I don't know how anyone could argue against taking it easy for a few hundred miles to make sure everything's ok and let everything settle

 

Oh no... not the dreaded ASE certified question! (Withholding RAGE)
I'm Ford certified (which is a REAL certification)
And the mechanic would tell you to take it easy for a few reasons.
1) they have always used break in procedures because that's what daddy did
2) they want piece of mind knowing you wont be back that day with screwed up gears because the got the lash wrong.

 

Didn't say it was a bad thing.. I said it is unnecessary. And obviously there are a lot of "bad" Ford certified techs. You can tell by the number of fords entering the dealer with a problem and not getting it fixed.... oh wait... they all do get fixed

 

Haha I'm sure no car has come back to a ford dealer with the same problem or misdiagnose, anyways it's good to let it go thru it's heat cycle, from what I've been told when gears are first install the finish generates a lot of heat until a pattern is worn in but I could be wrong, that's just what my dad and mechanic said

Also none of my gear installs ever whined or made any noise

 

Oh yes cause all issues are super easy to figure out! That's why you bring it to us!
None of my gears have whined either and I drive the **** out of them
I better find an ASE tech to clear things up for me

 

My girl had a break in procedure.........


and its on going every night....

 

What so bad about ASE cert? ain't that the industry standard??

As a welder I'm ASME and AWS cert'ed and work in and ISO 9008 shop

 

Having my gears professionally done by a trusted mechanic. I'll let you guys know what he recommends for the sake of discussion. I'm most likely with going with texastboneking's advice though - training & experience on the specific application trumps generalized advice.

 

Because any Joe blow off the street can study a book and take a test and become ASE certified without ever touching a wrench.
Ford certifications take several tests as well as hands on with vehicles to be obtained.
Big difference between the two

 

WTF DUDE!!! ffended: lol

 

Sorry Joe!

 

Well, I am generally a person with bad luck when it comes to things that I enjoy. I opted to follow my mechanics advice and take it easy for the first bit. I was all ready to give them a real test today, but its effing snowing out!!!!

Anyways, is there a market for used 3.55's? I have a posting over at the Thunderbird SuperCoupe club of America website. Is there a market for them on this board?

 

April and snowing... thank you al gore and your global warming....

 

I just got my mustang back from the mechanic with the gears installed and he took his time and did it right. He has done a lot of rear ends and has never had one whine. He's tested it out with no whine, and I've confirmed it as well. I asked him about break in, and he said that I don't need to do anything different - the gears will settle in but it is installed so that will be within the tolerances. Also, he's ASE Master certified.