Gear break in time?

[LVMarauder]

I was talking to my friend in the Silver State Mustang Club who just put 4.30's in his car. He says theres a 300-400 mile break in time and that he cant race right away cuz it will "scar" the gears and there will be a bad whine, however at this point I hear nothing while riding in his car. He generally knows what he is talking about so is this true?

[Petrograde]

hmmm,... makes sense to me. Gears will create a wear pattern after some use. IF your bangin' gears hard from the start your wear pattern might look like a chain saw.

Tom

[Kelly]

I was talking to my friend in the Silver State Mustang Club who just put 4.30's in his car. He says theres a 300-400 mile break in time and that he cant race right away cuz it will "scar" the gears and there will be a bad whine, however at this point I hear nothing while riding in his car. He generally knows what he is talking about so is this true?


Yes, new gear sets are to be broken in by driving for 10-20 miles at normal highway speed and then let to cool for about 1-2 hours and then repeat this step 2-3 times and then no heavy footed driving for 200-300 miles.

[HwyCruiser]

Here's a "do it yourself" (I didn't) set of gear installation instructions from Richmond that talks about break-in period near the end:

http://www.richmondgear.com/01instructions.html

I went with DR's Stage 1 Ford Racing 4.10 ring & pinion set, so I'm not pushing Richmond at all. My installer went through the 10 mi street drive, 30 min cooldown, three times procedure. I did it again just to make myself happy and then went about my business.

The 200-300 mi breaking is said to be needed before towing. No reason not to be extra cautious though.

-JD

[CRUZTAKER]

What Kelly said, and vary the speeds over atleast 200 miles to break in. Drive some in reverse as wll.

[Mattsmerc]

could you put the car on the jacks to get these miles or do you need the load from actual road miles?

[Kelly]

could you put the car on the jacks to get these miles or do you need the load from actual road miles?

Letting the car run on jacks is never a good idea :rasta: and the load from the car is needed.

[Agent M79]

I've been told yes and no by people that should know better than I.

My presumption is that new Ford 4.10's, 4.30's, 4.56's etc. is that the gears you got with the car are not "broke in" either. Dunno about you, but I got my car with 8 or 9 miles on it.

The manual said:


BREAKING-IN YOUR VEHICLE


Your vehicle does not need an extensive break-in. Try not to drive

continuously at the same speed for the first 1,600 km (1,000 miles) of

new vehicle operation. Vary your speed to allow parts to adjust themselves to other parts.


Drive your new vehicle at least 800 km (500 miles) before towing a trailer.


Presuming further, I can't image that Ford would advise you to do something that could lead to premature failure which they in turn would need to pay for as a warranty repair. Yeesh, enough Ford stuff breaks without them giving bad advice to contribute to it.

[BillyGman]

that's probably because the MM comes stock w/3.55's and when you go w/lower gears (meaning numericaly higher) such as 4.10's, 4.30's, or 4.56's the pinion bearings can heat up easier during the first few miles due to the higher turning speed of the smaller pinion gears of these ratios than the stock ratio pinion turns.

But this is a topic that's bean debated about soooo much on here before, and frankly I don't think it's even worth spending too much time arguing about. The bottom line is, if you're concerned about this, then simply take it through a short break-in period. After all, it can't hurt. But to each his own.

[Agent M79]

The bottom line is, if you're concerned about this, then simply take it through a short break-in period. After all, it can't hurt.
This'll work.

[MitchB]

The following is a quote from Bill Woboken in response to a similar question a while back on another board. Bill is a friend of Jerry and did work for Ford as a driveline engineer.

Mitch

______________________________ ____________________

Today's Lesson: Self-Control.


BillW

There IS a break-in period for rear axles, or a new gear set.

Drive at varying moderate speeds (<60 mph) at moderate loads (NO WOT!!)for about 500 miles.

Change the fluid. If it looks like black metallic paint, you will understand why I suggest this.

If you do not follow this procedure, (aside from a crappy pattern emerging from brinelling/sfc checking on the tooth profile, and run high highway speeds and do hard shifts (big, short duration torque reversals) with either manual or automatics set up per Jerry's thesis,) a phenomena called "bump scoring" can occur. This is actually a breakthrough of the hardened surface to the soft, chewy center of the tooth, the part that provides strength but not wear resistance.

I have actually tested under extreme conditions (120F ambients, 80 mph cruise for 40 miles on a "green" axle) a Mustang Cobra 3.27 axle which actually got the axle lube to the smoke point (>400F)and very close to flashover. Now, subtract the appropriate amount from the 120F ambient to a typical summer day and you'll still find that the axle lube overtemps.

This overtemp condition results in a breakdown of the lube layer and can do great damage to the tooth finish and even close up allowances for expansion vs normal tooth mesh....GRRRRIIINNNNNNNNNDDDD! !!

Hope this helps.

BillW

"Honey, what's whining in the back of the car?"

"I TOLD you not to invite your mother!!"

"She's NOT in the car!"

"Oh, it's the axle...uh, um, sorry dear."

[hitchhiker]

I was talking to my friend in the Silver State Mustang Club who just put 4.30's in his car. He says theres a 300-400 mile break in time and that he cant race right away cuz it will "scar" the gears and there will be a bad whine, however at this point I hear nothing while riding in his car. He generally knows what he is talking about so is this true?
Is this also true for any newly delivered MM?

Thanks,

David