Gear Break in...umm this is new..??

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Sounds like everyone's an expert here on gear break in, because they ripped on their new gears and didn't break anything. LOL

Here's a good rundown by Amsoil on why it's a good idea to "break in" your gears.

http://www.upmpg.com/lubricationnews/differential_maintenance/

To me, it's saying that the break in period is the highest temps your axle will see. That's enough for me to not want to see what stress the gears are capable of, when I haven't even had a chance to set the wear pattern on 'em.

Every gear set I've ever bought and installed, I've broke in. /shrug

I agree that it's not a bad idea to change the diff fluid as part of maintence and it's not a bad idea to take it easy on new gears but 99 percent of the time improper install is the reason I see failures.

I have never seen anybody change the rear end fluid after the cars break in period also I have never seen a bearing or ring and pinion failure in a factory setup rear with under 30k mile on it. every failure I have come accross in a new car was due to a bad setup done durring a gear install..

8.8's even from the factory do suffer from pinion bearing failures but this is in higher mileage cars and trucks.
 
"All new gear sets require a break- period to prevent damage from overheating. After driving the first 15 or 20 miles you MUST let the differential cool for 30-40 minutes before proceeding. Drive the first 500 easy miles and then change the oil after the first 500 miles."

This is a new one, Ive had gears in all 4 stangs Ive owned and this was the first time Id seen this...


That's nothing new. It's been around for a while. I'm more surprised that you are on your 5th gear change and just finding this out.


Gears need to be heat cycled. All that does is releive internal stresses. That;s why you are supposed to drive it easy and then let it cool down. You are not "wearing" anything in together, you are heat cyling them which will physically make the gears slightly stonger since there are no more internal stresses.

I would consider that important enough to pay attention to
 
My GT i did go easy on them, but for the past 2 Cobras I have had getting 4.10's and now 4.30's in this one, I got on it sideways leaving out the door:D

Not the best way to set them in, but damn was it fun. 5 years later, no issues.
 
Damn I posted in this thread BEFORE I even had my gears...:lol:

I drove easy on them, let them cool for probaly 6-8 hours, drove easy on them again, sat for a few more hours... next morning gave it effin hell!!!
 
For a 96-98 car it is a manual speed sensor that corresponds to the gear ratio. You can look around online to find the right application for yours. I think www.50resto.com sells them.

99+ Stangs are electronic and can be adjusted with a tuner electronically.
 
Ya it seemed a bit extreme..I can understand about the changing of the gear oil, that makes since and its true...but the 15 minutes and cooling..ya NO..mayby with 4:50+

Just install a new set, drive for 30 minutes, then crawl under the car and put your hand on the differential cover. Be prepared to remove it _quickly_ as it will be hot. _very_ hot. The reduced driving up front prevents damaging the differential oil. After a hundred miles, things are seated better and the temp drops way down. You can eliminate some of this by installing with a little more backlash, but then it will be a bit noisier. circle-track drivers use 2x the backlash we would normally use...