New Gears Breain-in

[ArXane]

Im getting the truck re-geared next week. What is the general consensus of what the break-in period should be? Do I need change the oil after "X" amount of miles? If so, I dont really want to put in Royal purple for only a couple hundred miles. How long before I can tow with them?

[layson]

What does the guy say that is swapping your gears?

[ArXane]

I havent asked him yet, ive often found that I get better info from forum members then mechanics or other "professionals"

[layson]

well I am getting my gears done soon, so I figured I would ask..

[ArXane]

Originally Posted by layson

well I am getting my gears done soon, so I figured I would ask..

My response may of came across wrong, wasn't trying to be a jerk... What I meant to say is that I just havent asked the installer yet and that I wanted to check forums.

[DeuceFifty]

first 20 miles (drive home from shop) go easy, no jackrabbit starts, stay under 2k rpm and take the truck home and let the differential get "cool to the touch"
21-100 Miles- easy stay under 2k rpms, try to stay under 65 mph
101-500-easy stay under or at 2k rpms, no jackrabbit starts

At 500 miles, Change the differential oil. When you get the gears installed use whatever the base oil they shop offers. at the 500 mile oil change, get royal purple and be done with it. The oil change is necessary to remove any gunk, shavings, or impurities that are in your axle as result of the break-in process.
The reason you go easy on the acceleration is because there is alot of heat and friction being generated in you differential case. If it gets to hot from being overworked, the oil will break down and the gearset will warp or give-out.

[ArXane]

Thank you for the detailed reply. The rear end calls for Synthetic, do I still have to run synthetic in the break-in period?

[Eagle 33]

how much are you guys paying for gears? up here in New England they want $900 per axle

[DeuceFifty]

put in whatever the manual asks for. In my f150 with 9.75 rear end, it was 75w140. i'm pretty sure that the 10.25's and 10.50's ask for the same stuff. My note about the RP is that its high grade synthetic and you dont wanna drop a bunch of cash on it off the get go and watch 100 bucks worth of stinky gear oil drain out, and then dump 100 more right back in.

The ford or lucas branded gear oil will not cost nearly as much. I think 30-40 vs 100+ for RP.


Eagle: Its 250 for labor on a solid axle and about 375 for a good gearset (yukon) and bearings here. I see you have an f150 in your pic. when i had gears done in my old truck, it was almost 450 bucks for labor on the IFS because they have to remove it from the truck, unlike the solid axle where they just pop the case.

[Eagle 33]

their price was if the axles were already out of the truck. I was planning on doing a lift so they would have been out from under the truck anyway. but the gears killed my budget and i'd rather have the gears then lift it rather than lift it then do gears.