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Why break in new gears?

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Old May 18, 2008 | 09:35 AM
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Default Why break in new gears?

When cars are purchased new, we often see guys at the track. Also, guys without daily drivers aren't driving 500 miles to break in new gears. I went 77000 miles on my 3.42's from the factory without ever changing the fluid and still had no issues and no whine when I changed them. (And my car doesn't crank without at least one WOT during the drive) So, why do gears need to be broken in?
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Old May 18, 2008 | 12:29 PM
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Because you have two surfaces that wear against each other. When parts are new, those surfaces don't match up perfectly. The break-in procedures are there to allow for the surfaces to establish a perfect match and a controlled wear pattern--providing a long service life for the parts. If you skip the break-in, there is a chance you can overheat and damage the contact surfaces.
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Old May 18, 2008 | 01:43 PM
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The break in period is not determined by miles but instead by heat cycles. All you need to do is go through 2 heat cycles consisting of drivinmg the car for about 15 minutes and then letting everything cool off completely.
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Old May 18, 2008 | 07:43 PM
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Originally Posted by Bad Blu Formula
The break in period is not determined by miles but instead by heat cycles. All you need to do is go through 2 heat cycles consisting of drivinmg the car for about 15 minutes and then letting everything cool off completely.
I'm on heat cycle number 6 and I'm going to drive mon- fri 35 miles to work cool for 8 hours then back. By Sat., I'm romping on it.
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Old May 18, 2008 | 09:46 PM
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absolutly no damn reason, their gears, drop the clutch at 5,000rpm that will break um in
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Old May 18, 2008 | 09:59 PM
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Originally Posted by alamantia
absolutly no damn reason, their gears, drop the clutch at 5,000rpm that will break um in
That's my method...been working for years.
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Old May 18, 2008 | 10:01 PM
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so's mine
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Old May 19, 2008 | 08:28 AM
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well if im told to break mine in i'll assure you im gonna break those ******* in! Just dropped some cheddar off on a brand new 12 bolt from moser fully assembled... not gonna risk tearing it up after spending that kind of cash! if you are told to break them in i say why not be patient and break the ******* in!
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Old May 19, 2008 | 08:39 AM
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Manufacturers recommend a 500 mile break in for new cars.
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Old May 19, 2008 | 09:47 AM
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Originally Posted by CW00BlackTA
Because you have two surfaces that wear against each other. When parts are new, those surfaces don't match up perfectly. The break-in procedures are there to allow for the surfaces to establish a perfect match and a controlled wear pattern--providing a long service life for the parts. If you skip the break-in, there is a chance you can overheat and damage the contact surfaces.
That's great...I wasn't aware you had to break in new gears...I had mine done about 3 months ago and I have been rallying the hell out of them since
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Old May 19, 2008 | 10:57 AM
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You dont. Anyone ever buy a new car that was rear wheel drive? Is the rear quiet? How many heat cycles did you drive it when you picked it up from the dealer? I assure the factory doesnt heat cycle their cars. Whine is caused by improper set up. You should be more concerned with new bearings than a contact pattern. No matter how you drive the car, hypoid gears will establish a pattern on their own. Gears are heat treated to about 1600 degrees F before they leave the plant. There is nothing that a few 200-300 degree heat cycles will do to help. Doing the heat cycle thing certinly will not hurt your car but it wont help it either. So if you want to go believeing it helps, go ahead. Drive it for 1000 miles and chaing the oil to flush out any debres caused by the bearings and your good.
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Old May 19, 2008 | 12:14 PM
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Originally Posted by alamantia
You dont. Anyone ever buy a new car that was rear wheel drive? Is the rear quiet? How many heat cycles did you drive it when you picked it up from the dealer? I assure the factory doesnt heat cycle their cars. Whine is caused by improper set up. You should be more concerned with new bearings than a contact pattern. No matter how you drive the car, hypoid gears will establish a pattern on their own. Gears are heat treated to about 1600 degrees F before they leave the plant. There is nothing that a few 200-300 degree heat cycles will do to help. Doing the heat cycle thing certinly will not hurt your car but it wont help it either. So if you want to go believeing it helps, go ahead. Drive it for 1000 miles and chaing the oil to flush out any debres caused by the bearings and your good.
I was gonna say...feel a little better now about the miles I have put on since.
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Old May 19, 2008 | 12:43 PM
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I got new 3:73's..very little whine..I have just been driving it normal..Got almost 500 miles on them..After it hit 1,000 changing the lube and done..
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Old May 19, 2008 | 01:06 PM
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Break in...? Who the hell has patience for break in.

If mine break... I'll put new ones in.
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Old May 19, 2008 | 01:10 PM
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Never broke mine in 5 years ago..373's..just fine..GM Gears..Experts installed them.[Shop called 'Rear Ends Only']
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Old May 19, 2008 | 01:21 PM
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Originally Posted by Nautilus
Break in...? Who the hell has patience for break in.

If mine break... I'll put new ones in.
ROFL...So true
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Old May 19, 2008 | 01:27 PM
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i usually do a couple heat cycles on mine. they start out nice and quite, but once you hit the track with slicks a few times..... there is no hope, lol. let the noise begin!
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Old May 19, 2008 | 01:29 PM
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Break in is extremely important to enusre you do not overheat the gears and burn them up. When you buy a new car the dealer recommends a break in on the motor right? In reality you are breaking in the entire drivetrain. The first 100 miles is the most important for "Heat Cycles". Drive 15-20 minutes increments then cool for 15 minutes. Once 100 miles approaches distance wise is no problem. No track time until 500 miles and the fluid is changed.

Jeff
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Old May 19, 2008 | 01:31 PM
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Originally Posted by Jawsgear
Break in is extremely important to enusre you do not overheat the gears and burn them up. When you buy a new car the dealer recommends a break in on the motor right? In reality you are breaking in the entire drivetrain. The first 100 miles is the most important for "Heat Cycles". Drive 15-20 minutes increments then cool for 15 minutes. Once 100 miles approaches distance wise is no problem. No track time until 500 miles and the fluid is changed.

Jeff
YA--should have stated I took it easy and changed fluid after 400 miles or so...
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Old May 19, 2008 | 01:32 PM
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How come new cars don't require that? or do they?
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