Re Gear Time. Have A Few Questions

[daniel3507]

In the next few days I will be re gearing my truck and am wondering what kind of break in period there is with new gears. Ive heard that new gears can create lots of small metal flakes when they are new but I have not heard how long I should let them go before I replace the fluid with synthetic. Any advice would be great.

 

[Dave Bennett]

500 mile of mellow driving (no towing, no long highway at high rpm) and then change the diff fluid. That will allow the gear to "break in".

Worked for me :costumed-smiley-007

 

[Jeep]

500 mile of mellow driving (no towing, no long highway at high rpm) and then change the diff fluid. That will allow the gear to "break in".

Worked for me :costumed-smiley-007

Yup.

 

[Rexsname]

When I did mine I spent all day driving on dirt roads. I was in four wheel drive (to do both differentials) and varied my speed. Speed up to about 45 or so and then coast down to about 15. Even tho "everyone" said to make this procedure last 500 miles I could only fit 275 miles of dirt into my break-in day. I drove it gently the next day and changed to synthetic oil right after I reached 500 miles.

What kind of vehicle will you be re-gearing?

REX

 

[01tundra]

500 mile of mellow driving (no towing, no long highway at high rpm) and then change the diff fluid. That will allow the gear to "break in".

Worked for me :costumed-smiley-007

This, but first break the gears in properly -

After install is complete, drive about 30 minutes and then stop and let the diffs completely cool - then 500 miles with no towing and change the fluid. I'm personally not a fan of synthetic diff fluid, it's really thin - ask somebody like Dynatrac and they'll tell you not to use it in their diffs....they prefer the good 'ole dinosaur oil .

My front are typically broke it by hammering them on the trail since we don't really get snow here and I don't like driving in 4WD on dry roads, I have tried to break the front in by running a little on a gravel road before.....but haven't noticed any difference in performance when compared to the fronts that I never broke in......

 

[daniel3507]

Thanks for the help guys. Im re-gearing my Ford Ranger now and then after I find a new motor and trans for my Bronco I will also be doing it.

 

[Bighead]

I used this guidance when breaking in my gears (From Sonoran Steel site). Haven't had a problem in 8+ years (knock on wood ):

 

[dustboy]

Detroit (Eaton) does not recommend Syn oil in any of their diffs, AFAIK.

 

[daniel3507]

I am having second thoughts about the synthetic. What all are some of you guys running in your diffs? Its an open diff if that matters much

 

[chasespeed]

Synth here... in everything but the engine.... 3 gallons of synth 20/50 would be my fuel bill for the month.....

Why not solve that open diff while you are re-gearing... BEST time to do it...

Chase

 

[78Bronco]

Get or make up a magnetic fill plug too. It collects any ferrous metal bits in your diff oil and gives you a good indication if all is happy in there with periodic checking.

I would break them in with decent conventional oil then switch to synthetic later if you can justify the costs.

 

[daniel3507]

Believe me, I would love to lock it up but dont have the cash for that at the moment.