Hey Everybody,

Now that the new factory Ford 4.30 ring and pinion gears are in, any advice on the "break-in" of them?

I have read SOOOO many differing opinions on aftermarket gears, but not many touch on the factory ones. The tech who installed them (and has been doing just that for 20+ years at Ford) told me that driving easy on them for about 250 miles is all that is needed. He said that driving 20 miles down the road and pulling over for 30 minutes for 2 or 3 cycles isn't really necessary on the factory gear sets.

Basically he said:
1. Drive easy for the first 250 miles
2. Don't tow anything until after this period
3. Take a short break after the first 30 miles of towing trailer and let the gears cool. Only need to do this once.
4. Now drive it and quit worrying about them.

So, is this sound advice? Don't want to screw up the perfectly quiet gears I just got installed.

Thanks,

James

 

There is no break in and like I said before, those gears are extremely hard which is why your old ones are as good as new still. They don't wear in and they don't wear out. There are no hard or soft gears, they are all tempered and case hardened steel. OEM gears are nothing special but they probably have a smaller percentage of miscut sets. Imagine breaking in a 17 jewel watch.........it doesn't happen.

 

Thanks Brent!
One last thing though, have you ever changed out the gear oil after the first 500 to 1000 miles on a new gear set? It is what I have done on the two sets I have had... but wonder if I was just flushing expensive oil and LS additive down the drain for no reason? Of course I changed it because someone who knew more than I did about gears told me to....

James

 

I like to change the oil after my first 500 miles on new gears.

 

There is a break in period on new factory gears. It's in the owner's manual.

 

I think it's a waste of oil, the factory doesn't recommend it.

 

Thanks Mark!
I looked in my owner's manual, but did not see it. I am assuming it is at least "close" to what the dealer tech told me to do?

 

I don't see it in my manual, what page it it on? Also, he doesn't have a new rear end, just the gears and they don't break in.

 

I didn't really do anything with mine when they were installed in fact I think I even pulled my fifth wheel with them within the first 100 miles, I did change the fluid after the first couple hundred miles whether or not I needed to I am not sure I just did what the shop that installed them told me to do, And that is probably what it boils down to from a warranty stand point do what Ford told you to do and enjoy your new gears...

 

Page 3.

Stewart

 

Thanks to all for your feedback on this issue!

So, according to the manual...there is really no specific break-in procedure except to vary the speeds frequently for the first 1000 miles.

Am I going to mess anything up by towing within the first 400-500 miles??

I think I will go ahead and drain and refill as that seems to be a common denominator in all that I have read.

James

 

You wont hurt anything towing but like I said above from a warranty from Ford standpoint I would just follow the techs suggestions ...

 

This is what I will do.
Im mainly curious as to what the REAL answer is regarding gear break in.

 

I did my 4.30's myself (i'm a tech) i did mine in feb. 07 and didn't tow untill may 07. There really is no special break in procedure, other than the 500 mile interval like your tech said. My commute at the time mimicked what he told you so i just drove to and from work, 12 miles one way with speeds ranging from 35-55 mph! Just drive it normally and you'll be ok. I have 50k mi. On my ford gears now and they are just as quiet as the day i installed them.

BTW, maybe i missed it, but what was the whole outcome with your noise and vibration?

 

Thank you for your input on this. Coming straight from a Ford tech it helps a lot.

As for the outcome of all the drama? For your leisurely reading pleasure:
https://www.ford-trucks.com/forums/1...ease-help.html

You can skip to the last couple of pages and get the gist of it all.

James