Improving the MN gearbox shift feel & operation.

[sierra]

what do people think about using the gl-4 instead of the recomended gl-3? as far as i know it will corrode yellow metals if we have any in our boxes? do we?

I'm running Penrite Sin Gear 75W-90 full synthetic API GL-5/6 in mine.
The tech at Penrite assured me there was nothing in it that would corrode copper and brass. His only concern was that the shift might be a bit tight, especially when cold.
The shift is the best it's ever been and the gear rumble in neutral when hot has faded to insignificance.

I used to worry about that too but I don't anymore,

[alan_blue]

Has anyone taken it back in complaining about the poor shift? Wonder what Mitsui would say?

[Froggy]

Has anyone taken it back in complaining about the poor shift? Wonder what Mitsui would say?

"No fault found. Go away" more than likely.
It's a gearbox designed for light trucks so it's going to be clunky. Come drive my Isuzu FRR 500 at work if you want clunky!

[sierra]

Has anyone taken it back in complaining about the poor shift? Wonder what Mitsui would say?

The shift on mine is excellent, especially when warmed up.
It's quite quick with good feel.

[alan_blue]

Nice hope it stays that way. Trying to find some more info on gl3 and 4 compatibility

[Brayden's dad]

Hi,

I'm enjoying this thread and am doing it after chrissy....I don't have any g/box problems but prevention is better than cure.

Problem is, people are using different oils....I'm not sure which one to use????

Regards,
Troy

[Kegsy]

I'm starting to think it doesn't matter what oil you use... just change it frequently.

When I get my new gearbox (number 3) I'll be doing 10k oil changes

[alan_blue]

There must be a reason why they specify gl3 and not 4 im thinking. Gonna see what gl3 oils are around and get back to you

[Longranger1]

There must be a reason why they specify gl3 and not 4 im thinking. Gonna see what gl3 oils are around and get back to you

Good luck finding gl3.

Since some of these gearboxes still crap out with the original fill oil in them so I don't think it matters all that much.

I think Kegsy is on the money with extra oil changes - it can't hurt. At least dump the original oil out early on. I did this and still haven't had any problems at all in mine.

Some have drama others do not for some reason. The only issue I've had is the transfer lever locking in 4H (not locked centre). Easily fixed by installing a small spacer collar to drop the white nylon bushing 2mm deeper to prevent it locking. Only happened the one occasion and has been ok since.

[alan_blue]

But that had nothing to do with the oil did it mate?

[sierra]

I dropped the original oil very early and it was like piss and filthy. Since then i've tried several oils in an effort to shut up the rollover and rumble at idle when hot. Finally I have found the oil that shuts it up and gives an excellent shift too. It's been in for about 8,000km and is as good as the day it first went in.
Problem solved and It wont get changed for a long time.

[Longranger1]

But that had nothing to do with the oil did it mate?

Transfer lever issue? No.

[Brayden's dad]

Now, I'm not so sure if I should do anything....

[alan_blue]

did you buy an oil yet?

[srb]

You won't find any GL3... Even your dealers wont be using it. GL4 is what's recommended by your dealer.
It was recommended to me NOT to use a GL5 or GL6 spec oils... These are too slippery for our synchro's apparently and make it even harder to change gear. I use Nulon GL4 full synthetic 75w-85 in gearbox and transfer. Never had a problem, shifts as smooth as silk. Best thing you can do with these G-boxes is change oil regularly every 10-15k I reckon, too many people having problems to ignore.

[homer56]

im a big beleaver in mobil full synthetic oils.in engine,gearbox, diffs, transfer case,power steering and break fluid and i also use full synthetic in both my road bikes big difference from mineral oils..my day job i drive a freightliner argosy semi,b/double,the only oil used in the 18 speed roadranger gearbox and the diffs are full synthetic nothing else can be used and is good for 400,000ks nothing but full synthetic for me its a lot dearer but will go the distance..hope you fix your gears my new triton is auto so im loving it

[sierra]

You won't find any GL3... Even your dealers wont be using it. GL4 is what's recommended by your dealer.
It was recommended to me NOT to use a GL5 or GL6 spec oils... These are too slippery for our synchro's apparently and make it even harder to change gear.

That's simply not true.
I have Penrite Sin Gear 75W-90 full synthetic API GL-5/6 in mine and the change is the best it's ever been.

[srb]

At sierra... Good for you mate, hope it keeps that way for ya. If you read my post properly is say's "apparently" not saying I'm right, just repeating what the so called experts tell me. You can do what you like at the end of the day. Also just out of curiosity... And yours being a 2wd ML... Does it have the same gearbox as the 4x4 MN.

[alan_blue]

Don't think they do as the 2wd call for gl4 and the 4wd is 3 as we know, seems you are ok to go one class up but not two

[srb]

Yeah come on sierra, we need to compare apples with apples here mate Bloody 2wd's

[sierra]

At sierra... Good for you mate, hope it keeps that way for ya. If you read my post properly is say's "apparently" not saying I'm right, just repeating what the so called experts tell me. You can do what you like at the end of the day. Also just out of curiosity... And yours being a 2wd ML... Does it have the same gearbox as the 4x4 MN.

4x2 has the same GL-3 spec as the 4x4 in my owner's manual.
It's got the same ratios, apparently.
I think the 2.4 petrol has a different box. The ratios are different and it feels different.
I doubt the 4x2 and 4x4 boxes are much different, especially in their gears, syncros and bearings.

It's the result you get from the oil that counts. Lots of talk but the only way to find out is to take 20 minutes and change it.
I don't agree with the regular change theory either. Once you fill it with the right high quality oil it should be good for at least 50,000km and probably 100,000km without being changed.

[alan_blue]

Yeah I agree with not changing it regularly as there is no need once you have the correct oil

[srb]

[salt36]

I have Penrite oil in my rebuilt V6 and love it...will be replacing the oil with Penrite every 7500 KLM'S

Will be switching to the Penrite gear and diff oils as well and changing them as per the Mitsi service book.....

[Kegsy]

Yeah I agree with not changing it regularly as there is no need once you have the correct oil

I use full synthetic penrite... still contaminates. These gearboxes (or my last two) have been shedding a fair bit of brass and metal into the oil.

This doesn't suggest a problem with the oil, rather the actual box. But having contaminated oil roll around inside only accelerates any dramas.

Hopefully my next gearbox is better with the "new design" parts that have recently come out and this isn't a problem. Both my current gearboxes were 2009 (MY10) gearboxes which seem to be the ones people have trouble with.

I throw in oil samples for testing when I do all the mobile heavy plant at my work. Oil analysis has shown a steep degradation in oil quality after 15,000kms...