Changing oil viscosity pros and cons

[XJR_Boy]

Hi all been a while since posting! I'm in need of the brains trust of bitog. I'm trying to get my son in laws Australian ranger 3.2 diesel sorted after a serious deficit in Maintenance.
It's done 280.000 kilometres and the transmission (manual) , transfer case and differentials have never been touched let alone checked the specs for the gearbox are CASTROL SYNTRANS FE 75W for gearbox and CASTROL AXLE GO-J 90
I've got a drum of 85/W/140 and with the milage on these diffs and gearbox never checked or inspected living in Qld Australia it does get around 5 Celsius in winter at night where he lives in winter would it be okay to use the 85/W/140 to save costs of buying new specced oil.they live in the country and lots of open road driving and towing horse float
If love to hear ideas and issues please if it will damage components vehicle is very neglected

 

[userfriendly]

You’re good to go with 85w140. Because of minus 40, I have to use a synthetic 75Wxx or 80Wxx. As long as it’s warmer outside than the pour point, I’m not worried about the channel point.

 

[SubieRubyRoo]

Hi all been a while since posting! I'm in need of the brains trust of bitog. I'm trying to get my son in laws Australian ranger 3.2 diesel sorted after a serious deficit in Maintenance.
It's done 280.000 kilometres and the transmission (manual) , transfer case and differentials have never been touched let alone checked the specs for the gearbox are CASTROL SYNTRANS FE 75W for gearbox and CASTROL AXLE GO-J 90
I've got a drum of 85/W/140 and with the milage on these diffs and gearbox never checked or inspected living in Qld Australia it does get around 5 Celsius in winter at night where he lives in winter would it be okay to use the 85/W/140 to save costs of buying new specced oil.they live in the country and lots of open road driving and towing horse float
If love to hear ideas and issues please if it will damage components vehicle is very neglected

Going up a step in viscosity almost never presents a concern, especially when the ambient temps are north of 100*F. If it otherwise meets the specs required you should be ok

 

[Passport1]

We have this Valvoline product here in the US. High quality and inexpensive. I've used it many times. Good results. Might work for you if Antipodians can source some.

 

[XJR_Boy]

Thanks guys!
I've got a 20 litre drum of 85w140 full synthetic trying to save the young fellow some money and just doubted myself hope you all had a great Christmas and holidays

 

[blufeb95]

Is the 85W140, GL-5 gear oil? That'd be perfectly fine in the diffs, but the original fluid specified for the transmission is a GL-4 fluid, if that transmission has bronze synchros, you don't want to run GL-5 fluid in it.

 

[aquariuscsm]

I would be careful going up oem spec viscosity in a standard transmission. Shifting action could stiffen and you may end up with gear clash.

 

[Jetronic]

Yes, the 85W-140 is excellent for the diffs and transfer case, but NOT the transmission.

 

[adams355]

Going up a step in viscosity almost never presents a concern, especially when the ambient temps are north of 100*F. If it otherwise meets the specs required you should be ok

Have you got any data on that or a linked study. I wouldn't be changing from what the service manual says to use.

 

[SubieRubyRoo]

Have you got any data on that or a linked study. I wouldn't be changing from what the service manual says to use.

That’s where the information comes from. Read your service manual, there will be a viscosity vs ambient temp chart that gives guidance like the ones below. Maybe next time…

 

[XJR_Boy]

Picture of the oil bellow of what I was going to use in gearbox,transfer case and diffs

In the gearbox seems too big a jump in viscosity I'll stick to specs for that I think

From what I've read on here and also spoken to professional gearbox builders the transfer case has Gears not chain so should be fine with the thicker oil as should the diffs

Thanks for the speedy replys

 

[blufeb95]

That's GL5 oil, it'd probably be fine in the transfer case and definitely fine in the diffs, but I don't know how that manual transmission is, if it uses either brass or bronze synchronizers, you don't want to put GL-5 gear oil it it, at best it'll degrade the shift quality because it'll make the synchro stick and at worst it'll soften the synchros and cause them to fail very quickly.