I’m looking for technical help or recommendations on: Gearbox Oil
Morning Everyone…
After trawling through various forums & videos (Richard Fanders one is great) I’m left with more questions than answers on what Gearbox oil is best for everyday driving.
From what I read and watch, genuine oil is best for slick changes, and for track use/hard driving Millers Oil?
This leaves me a dilemma.
Genuine oil hard to get, Mazda garages near me have terrible reviews on their service depts.
Car is a daily for the other half, but I drive it hard at weekends.
Considering above I’m absolutely baffled on what to put in the thing, the car gets driven all week in all weather, so I don’t want a box oil that gives terrible shifts for the first 20 min (apparently millers is like that when cold)
I hear redline MTF is good but again, I see mixed opinion, some say only crunchy shifts for first mile, others say first 20 min it’s terrible.
Based on this what oil do I go for in a daily driver, considering it’s an every day car in cold & warm weather…
Hello millers
Given your name you could try Millers Oils??
Better still get in touch with Paul at Roddisons Motorsport Sheffield S9 1US 0114244 5300, Paul has vast knowledge & will give sound advice.
Cheers
Keith
Thank you, yeah I saw the 75/90 millers is what appears to give cold shift problems, I see BlueAgave says about the millers 75/80 (never realised this was an option) so I think im gonna give that a go and report back in a few weeks once sorted, doing a roadtrip not long after so can do a “long term” report lol.
YOu might have saw that that R. Flanders video discussed that he thought the often recommended Millers in 75w-90 grade was awful until warmed up.
If you don’t go with the Mazda stuff, remember that the OEM oil is 75w-80 (Mazda themselves told me and Flanders), if considering something else. SO as mentioned above, if you’re going to go Millers, 75w-80.
Personally I liked the shift for the first 5 years. I got it changed in a dealer with the Mazda stuff (I saw the drum). Hence it shifts as good as before (better in fact!).
Look forward to your results.
Thank you for the response, yeah that’s good to know, I’ve got the millers 75/80 on order for the box and the genuine Mazda stuff for the dif, hopefully keeps the shift nice and silky!
It’ll be good to know as a direct comparison to the OEM oil, which I presume is in your car (maybe it hasn’t been changed yet)
Despite the OEM grade being 75W-80, I’m not sure of anyone on the forum who’s gone that route, as most go to 75w-90. If you read around the forum, you’ll see that even some dealers haven’t put the Mazda oil in there either(!!) when users had their gearbox oil changed. So if your Miller’s 75W-80 EE turns out great, It’ll be a great alternative to know about, keeping to the OEM grade.
Hope it turns out as good, or even better.
I just can’t see why the manual recommends 75/90 if it completely ruins the shift feel (and the OEM is 75/80), surely it can’t be good for the box to struggle like that, on our race bikes we run good oil that gives a smooth shift, and change often, usually every 5 hours race time.
I can see for track use you’d go a lot thicker as it’ll run at extreme temps.
I’m hoping this works out nicely as I’ve got some big roadtrips planned and I would quite happily change the box oil every year.
I’m fairly sure its OEM oil in it, however I’m not entirely sure whether its the from factory or it was changed, as the Mazda service log shows it on there but it’s missing in the details section, so I can only assume it hasn’t been done but the car had a fantastic main dealer service history before I bought it 2.5 years ago, and I’ve done oil changes every 4k since…
I use 75w/140 as recommended by Walter Motorsports due to the variable build quality of the gearbox. My Recaro has the V1 and I’m trying to make the gearbox last as long as possible. Gear changing is when cold is no worse than when I used 75w/90, when hot is silky smooth.
That’s really interesting to note, I do have plans to start tracking mine once we get the other half a daily as she won’t drive my van, but I’ve been very worried about the box exploding as mines a V1 too, I heard rodders upgrades them though, I wonder what that costs!
I know. I had a back and forth with Mazda a couple of years ago, questioning, at first, the 75w-80 grade, when like you say, its says 75w-90 as an alternative in the manual (but says nothing of 75w-80 in the manual). I thought they got the 80 bit wrong. But no, they said the Mazda juice is an 80, and gave a part number for the 20L drum (K020-W0-042R).
R.Flanders talks of similar in his video.
Very odd, not sure why they don’t just change it, however not the first time you see weird things from the Manufacturers.
Weirdest/funniest one to me is the Yz250s in the MX world, takes 750ml of gear oil, but an error means the check bolt is in the wrong place, and shows you “full” at 450ml, they never fixed this error because it would require redesigning/re-tooling and its been like it for 20 years
Sorry to jump on this thread as an NC owner but it’s really interesting and I was just wondering does anyone know if this theory of using 75W-80 instead of 75W-90 would work for helping cold shifts on an NC too?
