20 -50 oil in a MOD gearbox

[Stagdad]

I have heard tales that engine oil can be used in a manual gearbox with good results,better changes and no damage done apparently.

Any thoughts /experiences of such goings on as i have my box empty of oil at the moment.


Cheers Steve

[jleyton]

I've used Millers TRX semi synthetic 75/90 in O/D gearbox and diff and found it to be excellent - better gear change and quieter diff.

MD of Millers has got a Stag and uses it which must say something.

Cheers

Julian

[kgnich]

I have heard tales that engine oil can be used in a manual gearbox with good results,better changes and no damage done apparently.

Any thoughts /experiences of such goings on as i have my box empty of oil at the moment.


Cheers Steve

I have run my MOD with Millers 20/50 for about 10 years now and had no problems at all. (25k miles). It was recommended to me as a way of getting a smoother gear change without causing any damage. So far it seems to have worked really well.
Just my experience for you..... I know others will recommend original spec gearbox oil.

Graham

[Mike W]

I have been using 30wt ND for a number of years in my tr6pi manual with j-type od. works great, easier shifts when cold..seems to wear as good as with hypoy gear oil. several o/d rebuilders recommned it. Definately get non-detergent as i understand normal motor oils with detergents tend to foam in a manual transmission.

[marshman]

Personally I try to use the oil grades originally specified by the manufacturer. Having said that I know Mini's (the proper ones) have a gearbox that shares the engine oil (20W50), my Landy 110 LT77 box runs on ATF while the transfer box is EP80, My old Standard 8 had EP80 and my dads Peerless and my old Standard Vanguard (both with overdrive fitted) run on straight 30 (SAE30) oil. So in conclusion I think gearboxes are not that fussy! Kryten usually has the real answer as to what is "safe" to use and what is not.

Roger

[Stagdad]

Thanks guys ,may be i'll try some VR1 as i have some.

Cheers Steve

[NickA]

I thought there was a specific specification for engine oil that is used in combined engine/gearbox units as in the mini? If the gearbox shift are notchy wouldn't a lighter gearbox oil be a solution? Do engine oils have a life i.e are they designed to be changed at an interval where as gearbox oils are fill for life[1]. Long way of saying I don't know so I'll stick with what Mr Triumph specified


[1] not that I do this, I've just swapped all the oils on my X3 even though BMW says filled for life

[Stagdad]

Dont know about engine oil having a life Nick ,I thought it was the combustion process that degrades it.
Cheers Steve

[GDPR]

The 20/50 will be fine - as long as it is a good one, change at 24000 intervals or sooner if you are inclined.

EP was specified originally specced for the gearbox as was the only oil that would cope with helical cut gears - a good modern 20/50 will be every bit as good.

Differential is different - stay with EP as the gears are hypoid spiral cut to give the widest gear tooth contact but the contact pressures are much higher due to the sliding mesh action..

Russ

[andy p]

didn't take you long to get home, you must drove it like you stole it tonight, we wont mention on here the convo we had lol

The 20/50 will be fine - as long as it is a good one, change at 24000 intervals or sooner if you are inclined.

EP was specified originally specced for the gearbox as was the only oil that would cope with helical cut gears - a good modern 20/50 will be every bit as good.

Differential is different - stay with EP as the gears are hypoid spiral cut to give the widest gear tooth contact but the contact pressures are much higher due to the sliding mesh action..

Russ

[stag8manod]

Hi, I use Castrol VMX in the man/od gearboxes of my Spitfire and Stag also the 5 speed man box in my Ford Courier ute. It was also used in the 5spd Holden Commodore when we had it and cured the heavy baulking change when cold. Cheers Ian A

[blue 464]

{ was recommended to use 20/50 by fitchets after a problem with the o/d engageing, it didn`t help as the solenoid was sticky, but i left it in as the gear changes ar better especially with the oil cold, Derek

[Gresley]

Another vote here for Millers TRX 75/90. I have had it in my O/D gearbox for 55,000 miles without any problems.

Brian

[jleyton]

Glad you said that Brian

With all the talk of 20/50 etc I was worrying that I'd got too thick an oil, even though I've found it to be really good.

And there can't be much more of a test of it than your daily usage . Out of interest, do you use Millers for engine oil ? I use their Classic sport semi synthetic.

Cheers

Julian

[Mike Stevens]

With all the talk of 20/50 etc I was worrying that I'd got too thick an oil, even though I've found it to be really good.

It won't be too heavy weight Julian, the original spec was for 90 grade!

Interesting in the Millers TRX 75/90. I might give that a try in the Stag and PI. For best effect I'd better fix the dragging clutch first!

Cheers,
Mike.