We keep hearing about "change your ENGINE oil every 3000 miles" kind of crap.

but now Im wondering. how many miles should you "go" before you change, say Gear or the Rear Diff. oil.


I know it depends on your driving habbits or follow the manual blah blah blah.

Take me for example, I did my first Gear and Rear Diff. Oil change at around 5K miles. now I have 15K going to 16, and Im thinking about changing it.

Just want to get some ideas from all the cool guys out there like YOU!

*Edited* oh, I use RP 75w90 for both Gear and Rear Diff.

 

b/c the gear oil and rear diff. fluid are only used when the car is in motion you don't have to change it as often as engine oil. also, it's thicker than motor oil. i would change it around 60k

 

all other car change their tranny and diff @ 30k, I don't know why mazda put it @ 60k but I will be change it @ 30k as a minor service.

 

I changed at 12500 miles the tranny and the diff. oils. Mobil SHC 75-90 GL-4-GL-5 in the tranny, and Mobil SHC-LS GL-5 in the diff. I noticed there were a lot of metal parts on the magnetic oil screws, so I hardly beleive that changing these oils at 60k is OK. What forces this thought too, that the diff oil wasn't clean after 12500 miles.

 

Or..how about every 3 yr, regardless of mileage? Do it with your brake fluid drain..every 3 yr. would equal roughly 36K miles @12k/yr....not to mention, changing these fluid is relatively cheap when you factor in that they are changed every 3 yrs...

 

like Ayrton012 said. when I first change my gear/rear diff. oil, there were quite alot of tiny little metal stuff on the magnetic bolt. probably due to new parts breaking in. Now after another almost 11K miles. Im thinking about changing it again.

Its really a pain to change gear and rear diff. oil. so Im just going to bring my own oil to a shop and tell them to do it.

I baby my 8 too much !

 

I track my 8 so for my own piece of mind I change the trans and diff fluid every March which for me works out to every 25,000 miles.

 

i first did mine around 3-5k miles (Been 2 years now, so its hard to remember). I went to redline.

At 30k, I changed them again. this time royal purple.

Honestly, they both feel the exact same, both are better than the OEM fluids - easy to tell because the gear shifts are a lot smoother and silkier, but royal purple also feels good before the car has warmed up, while redline feels notchy till the transmission has warmed up.


if I was just buying new, I would recommend the first change at 5k, mostly to get rid of the shavings and other things from break-in, and every 30k from that point on. It's only like $50 worth of materials...

 

EXACTLY! Only $50!! So, do yourself a favor and change often..for me it will be every 3 yrs..for someone else that pushes the 8 harder, it might be 2 yrs..usage is up to you, but at least drain it every 3 yr to get some good stuff into our 8's..

 

Just got mine changed today.
Put some Royal Purple in.
It's quiet and shifts really nicely. (Like what was said above.)