What Is "Break In" Period For New Gears?

[98GTBlkConv]

Hey! Just had my 3.73's installed around 100 miles ago. When I picked up the car, the mechanic told me to let it break in for 500 miles. What does that mean? Is there a certain speed or rpm's I should not exceed while they are breaking in? He told me not to stay at the same speed for extended periods, but did not tell me anything else.

 

[StangLou]

it varies by who you talk to. i personally had mine revved all to hell the day of install. i was simply told not to like tach it up to 4000 and sidestep the clutch, or powershift for about 100-200 miles. I have had 0 problems with whine or any noise from the gears. g/f just got 3.73s put in hers and it was on the dyno the same day for 3 runs for a full tune on her chip. no noise from hers either. a lot of guys on here swear by 500 miles and dont take it past like 3000 rpms. i say your good to go though

 

[98GTBlkConv]

it varies by who you talk to. i personally had mine revved all to hell the day of install. i was simply told not to like tach it up to 4000 and sidestep the clutch, or powershift for about 100-200 miles. I have had 0 problems with whine or any noise from the gears. g/f just got 3.73s put in hers and it was on the dyno the same day for 3 runs for a full tune on her chip. no noise from hers either. a lot of guys on here swear by 500 miles and dont take it past like 3000 rpms. i say your good to go though

Wow! Don't think I would have put mine on a dyno the same day (personally) based on the "tone" of the mechanic. I guess it is hard steel, so unless I thrash the heck out of it, they should be fine! Besides, she's my baby and I treat her nice! I'll continue to listen to her purr to see if I hear any weird noises! Thanks!

 

[Rio96]

Breakin period, applies to
piston rings and cylinder walls.
Rio96

 

[Modular2v]

i would go about 200 miles before i thrashed her....i just had an eaton, 31spline mosers and 4.10s put in about 70 miles ago and i cranked her up to 5k rpms last night WOW!!! oh by the way, should have gone with 4.10s lol jk

 

[Defleshed]

usually they say not to wide open throttle it (floor it) for 500 miles, generally because the gears need to "set in" through heating up and cooling down. I couldnt wait and i floored it around 450. muhuahahah

 

[Madi98GT]

My break-in period for my 4.10s was 5mins, then slammed down the go pedal. My mechanic said no worries, everything has been fine.

 

[CManT1914]

I heard this too, so I asked my mechanic. I asked, "how long do I need to keep my foot out of it for them to break in?" He replied, "uh, about 10 feet." Depends on the mechanic, but I've had no problems with mine, and I was spinning my tires as soon as I pulled out onto the street.

 

[NewStangNewbee]

lol i hope not 500 I didnt go 5 ft. lol

 

[Rocketman]

I've read on a couple gear Mfg. web pages that it is recommended to do 3 heat cylcles. Run the car at normal hwy. speeds and let it cool all the way back down to room temp. This is recommended prior to towing. I would say WOT launches and quarter mile races would qualify as well.

 

[XTONKAX]

Another vote for no break-in period. If you trust that they've installed them correctly, there should be no problem. I've had zero problems.

 

[Mustang5L5]

I was romping out of it as soon as i got out to the street. I drove the car normally. 50,000 miles later the gears are still silent. (on my 5.0)

 

[98GtRioRed]

The proper break in period is the time it takes to back down the driveway.....then give 'em hell!!!!!!!!!!

 

[BNH4.6]

Same as above get on it!!!! I left from the gear install sideways. No problems at all.

 

[5.0's 4 ever]

I would agree with the no break in period. When I was putting the 4.30s in my cobra at my dealership I asked our suspension tech about a break in period. He said there is no need and I would tend to believe him since he has over 30+ years experience, can do a set of gears in his sleep, and I have had zero problems since the install.

 

[98GTBlkConv]

So, basically, what you guys are saying is "NO BREAK IN PERIOD NECESSARY"! LOL! It's been tough not breaking them loose just to see how much more she has! I have put over 150 miles on it so far without any weird noises or problems, and have had it in DC traffic once. So, it has plenty of time to heat and cool. So, it must be time to burn some rubber!

 

[03-s281]

My tuner said dont worry about it.
I DO have a gear whine. But I really didnt get on it for a couple days.
The gear whine is not as bad when I step on the gas, it when I'm just cruising.
It seems to have some kind of lag in it.

 

[Joel's98GT]

I've always been tought to wait 3 heat cycles.

 

[CottonBurnerz]

The guy who installed my gear (he own a 1000+ hp and 5 sec. stang) took my car for a ride after the install and gunned the car right away. I asked him about the 3 cycles and break in period thing. He said it's jut a myth and that people do it just to feel more secured or whatever. Just sharing my experiences..