Knucklehead Saloon Posted May 2, 2018 Share Posted May 2, 2018 Gday all, I'm running a 91 Brumby with the EA81 engine and the stock 4 speed trans with 218,000kms on the car. 16000 kms ago when I first got the car I changed out all the fluids including the g/box oil. I used a name brand mineral oil the correct weight and volume etc but it has only taken this ling for the shift quality to nose dive hard into sucks-ville. I'm guessing the mineral oil doesnt stand up so well. This time I went with a semi-synthetic oil and thought why not give that N70 stuff a go as well. I'm not usually a fan of mechanic in a bottle stuff but I'm thinking after 27 years of wear on the dogs and synchros in the box it can't hurt. Worst case scenario is if the stuff was crap I'll dump the oil and start again. Well... pleasant surprise. The new oil improved shift quality alot. After adding the N70 as well the box became realllllly smooth to operate and easily selects 1st gear while moving now. So far so good. I'll report back after I clock up some miles and let you know how its holding up. Cheers, Knucklehead. 1 Quote Link to comment Share on other sites More sharing options...
jono Posted May 3, 2018 Share Posted May 3, 2018 G70 is Australian secret...ssshhhh Quote Link to comment Share on other sites More sharing options...
skishop69 Posted May 4, 2018 Share Posted May 4, 2018 Never, never, never, did I mention never? Use mineral oil in an automotive application.Doesn't hold up to shearing forces and doesn't maintain the set viscosity it is rated at when place under high heat and shearing forces. Glad you got it out before the gearbox grenaded and that the new oil has brought it back. 1 Quote Link to comment Share on other sites More sharing options...
jono Posted May 4, 2018 Share Posted May 4, 2018 ?? Think we got here by using mineral oil, so long as it is correct application. I'm sure it was 80W90 and a mineral oil I have been using for decades in gearboxes and diffs. Unless that long lasting stench of gear oil indicates it is synthetic? Quote Link to comment Share on other sites More sharing options...
jkinz Posted May 4, 2018 Share Posted May 4, 2018 having never owned a vehicle with a good gearbox, I usually just run the recommended oil (typically 80w90) and learn when and how to shift so its happy... I've tried Lucas additive and found that it may improve operation when warm but it's really hard to get a good shift cold. I'd be curious if there's a US counterpart to N70 and if so, will it really improve my shift feel in the garbage vehicles I drive. Quote Link to comment Share on other sites More sharing options...
Knucklehead Saloon Posted May 4, 2018 Author Share Posted May 4, 2018 Sorry jkinz that was a typo. Its Nulon G70 not N70. Ebay linky https://rover.ebay.com/rover/0/0/0?mpre=https%3A%2F%2Fwww.ebay.com.au%2Fulk%2Fitm%2F331798313713 Quote Link to comment Share on other sites More sharing options...
Knucklehead Saloon Posted May 4, 2018 Author Share Posted May 4, 2018 Oh and you'll need the 250ml tube to treat 4l of oil (they also sell 125ml tubes of the stuff). Quote Link to comment Share on other sites More sharing options...
Knucklehead Saloon Posted May 4, 2018 Author Share Posted May 4, 2018 Jono: man gbox and diff oil smell disgusting regardless of synth / mineral. Almost makes me retch every time haha ! Quote Link to comment Share on other sites More sharing options...
DaveT Posted May 4, 2018 Share Posted May 4, 2018 Goes back a while, but when I had a 4 speed, - 1978 4WD wagon - I used Amsoil synthetic gear lube in it. It shifted nice even when it was sitting in 0 degree weather overnight. The normal stuff, it would be so gummy, the car would slow down so much by the time the shifter would move from 1st to 2nd, you almost wanted to be back in 1st. Quote Link to comment Share on other sites More sharing options...
Knucklehead Saloon Posted May 4, 2018 Author Share Posted May 4, 2018 Amsoil is the best DaveT !! Scary expensive down under though. Every oil test Ive ever seen put Amsoil out in top. Better than mobile1 full synth too. 1 Quote Link to comment Share on other sites More sharing options...
el_freddo Posted May 4, 2018 Share Posted May 4, 2018 I've never had an issue with mineral oil in my gearboxes. 2x Brumby, L series (off-roader) and my sister's liberty are all running a Penrite mineral gearbox oil of the required viscosity. No issues. Both brumbys shift nice too. The two other boxes are much nicer than the 4 speed to begin with. L series runs a modified phase2 box. No cold shifting issues like the original L's 5speed. I've never heard of this "mineral oil in gearboxes is not good for the box" type mantra. Sounds a bit like saying petrol isn't good for cars... Cheers Bennie Quote Link to comment Share on other sites More sharing options...
skishop69 Posted May 4, 2018 Share Posted May 4, 2018 I've never seen any good results from running mineral oil in automotive applications. I'm guessing what you have there is a group 3 or group 5 type mineral oil that has similar properties to synthetic oil, but still not quite as good. I'm referring to groups 1 and 2 which are not as well refined. Granted it's been a while since I changed my own oil (It's actually cheaper for me to let the lube monkeys at our dealership change it lol) But i don't seem to recall hardly any options for mineral oils here in the states. That may be do to the fact we have more oil for refining and ease of synthetic production. I was a bit hasty in my statement given you guys are using a better grade of mineral oil than what we typically see here. Quote Link to comment Share on other sites More sharing options...
Subasaurus Posted May 4, 2018 Share Posted May 4, 2018 Goes back a while, but when I had a 4 speed, - 1978 4WD wagon - I used Amsoil synthetic gear lube in it. It shifted nice even when it was sitting in 0 degree weather overnight. The normal stuff, it would be so gummy, the car would slow down so much by the time the shifter would move from 1st to 2nd, you almost wanted to be back in 1st. my 79 and 80 brat both are a bit glitchy on the gears using 80w90 the first 5 minutes of driving under 35 degrees, Amsoil isn't as easy to come by overhere, no one sells it in stores, so the only way to aquire it is online. Quote Link to comment Share on other sites More sharing options...
Subasaurus Posted May 4, 2018 Share Posted May 4, 2018 Amsoil is the best DaveT !! Scary expensive down under though. Every oil test Ive ever seen put Amsoil out in top. Better than mobile1 full synth too. agree, agree, and agree. Quote Link to comment Share on other sites More sharing options...
skishop69 Posted May 4, 2018 Share Posted May 4, 2018 I was wrong in my statement. I got to pondering it on my way to work because of the way you guys stated things. I got stuck on terminology. We in the states refer to it as motor oil, not mineral oil. Mineral oil has a different connotation in the states. The groups 3 & 5 I was referring to are motor oil. I apologize for my error. I really have to watch those early morning posts until I've had more coffee. Idiot. 1 Quote Link to comment Share on other sites More sharing options...
DaveT Posted May 4, 2018 Share Posted May 4, 2018 Yes it's expensive here too. I know everything is even worse down under. But it's a one time thing, at least for gearboxes. I found out about it from a Co worker around 30 years ago. After trying it on the first car, eventually switched to all their lubs. The ATF makes the 3ATs shift better, most notably when cold also. Run the engine oil with their bypass filters. Never change oil again. Back then, it was about 50$ a year to be a dealer, and get the stuff wholesale, so I did that. Never got into being a real sales man/ dealer, they recently changed things, now you can pay a lower amount for preferred customer pricing, or more to be a dealer, so I switched to pc. Quote Link to comment Share on other sites More sharing options...
Subasaurus Posted May 4, 2018 Share Posted May 4, 2018 I was wrong in my statement. I got to pondering it on my way to work because of the way you guys stated things. I got stuck on terminology. We in the states refer to it as motor oil, not mineral oil. Mineral oil has a different connotation in the states. The groups 3 & 5 I was referring to are motor oil. I apologize for my error. I really have to watch those early morning posts until I've had more coffee. Idiot. i thought the same thing at first, only earl should be going into engines. Quote Link to comment Share on other sites More sharing options...
jono Posted May 5, 2018 Share Posted May 5, 2018 I had a feeling ski shop may have been confused with mineral and motor oil. The latter not really suitable for extreme pressure or gears. Mind you, what did the old minis run in their engines with gearbox bathing in the engine sump? I also once tried engine oil in a gearbox as it was a dealer suggested option for cold climate. Box is still about 33 years later Quote Link to comment Share on other sites More sharing options...
Subaru Scott Posted May 5, 2018 Share Posted May 5, 2018 Motor oil is fine in gearboxes, motorcycles have done it forever. Just can't take the shearing of hypoid gears in a transaxle or differential. 1 Quote Link to comment Share on other sites More sharing options...
jkinz Posted May 10, 2018 Share Posted May 10, 2018 I too was reading mineral oil imagining running that stuff you buy for lubricating food safe machines or as it says on the bottle as an "intestinal lubricant" if you drink it... figured it was a terminology mixup. certain transmissions definitely run motor oil but I've not tried it in a subaru. My Dodge Getrag 5 speed runs 10w30 motor oil, I had an acura that took 10w30 or ATF per the FSM (thought that was strange), and ford rangers use ATF in their manual gearbox. Quote Link to comment Share on other sites More sharing options...
Knucklehead Saloon Posted May 11, 2018 Author Share Posted May 11, 2018 ATF is awesome stuff... A little off topic but I've run it in my harley primary (includes wet clutch) for 13 yrs now no problems. Clutch action is better with the ATF but you gotta run an older grade without the friction modifiers (D grade). A retired harley mech put me onto it, he had over 100k miles on his bike and no problems with the primary chain, sprockets or clutch in all that time. Oil always comes out clean too. Quote Link to comment Share on other sites More sharing options...
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