[whincup]

I've got brand new diff gears (4.57 from lowrange) with full rebuild kits, can anyone tell me if theres a specific run-in procedure for stuff like this? as in, avoid high speed for the first X kilometres, etc? i originally planned on driving to/from work for the first fortnight or so which is about 20km each way, half is highway though, is highway speed fine?

found very contradicting info online, some say just drive it normally, some have very detailed procedures involving specific speeds for specific distances, slowly increasing...

[jimmey]

free bump for curiosity.

[SierraDan]

The general consensus is 500km of low stress driving. I'd class that as a cruisy sub 80km/h.

I'd personally just drive on it normal for 500km and replace the oil.

It's just to wear in the machining and mesh the gears to each other. So there is some metal "dust" in the oil you should get rid of.

[christover1]

I always do 2 changes of oil after any diff job, one at 500 and next at 1500K.
Diff oil is way cheaper than diff gears.

[303zuke]

Depends on the installation.

If it was a "tip them out of the box and fit" job at home, I'd be running them in with careful driving for a few hundred Km.

If it was "Take the R&P set to a diff specialist and have them lapped and installed", then I'd jump in and drive like normal.

Either way, change the oil at 500Km.

If the gears are not lapped by a professional at installation, then when the gears do "wear in the machining, and mesh to each other", then the backlash will be out and you'll be left with a clunking diff and reduced life.

[whincup]

it was installed by the local arb store (airlockers & rebuild kit fitted at the same time), count as a professional or no? they say 2500km, not 500km for oil change. my plan was at 500 then at 1000. they also recommended 85w140 diff oil too. all sound right?

[jdk81]

I wouldn't call professional.

[whincup]

just further to this. is it a good idea to drive around in 4wd with hubs unlocked, or hubs locked 2wd just to get the front diff turning? obviously not 4wd AND hubs locked

[christover1]

I put mine in 4wd with hubs unlocked very regularly, to keep oil circulating.
Usually crawl up the driveway.
And lock hubs early when off roading, make sure oils warmed up.