Improving the MN gearbox shift feel & operation.

[Longranger1]

I finally got round to dropping the original gearbox oil in my MN GLX-R today (at 7000kms).

Results: Notchiness - gone, shift feel - dramatically improved, cold weather shifting - too soon to tell, quieter - yes.

Oil used: Penrite Sin Manual Trans 75w-85 full synthetic manual gearbox oil - 3.4 litres used.

I could not believe that it would make such a difference - highly recommended for those who love their Triton!

[mad992]

mate ive been meaning to do this for a long long time

[Longranger1]

Had the oil for some time, mine had improved with use anyway yet it still improved markedly . It is a bit of a bitch that they only supply 2.5 litre (too small) or 20 litre drums (What I bought ).

As I have plenty, I'll do the tranfer case and service the other car as well.

[dansan]

my triton has only done 5000k and yer definately have to get onto that oil change cause the oil in it is shit!!, do u know what the original oil is that they put in it when you purchase the car?

[slipn]

Had the oil for some time, mine had improved with use anyway yet it still improved markedly . It is a bit of a bitch that they only supply 2.5 litre (too small) or 20 litre drums (What I bought ).

Was it a hard job to do at home?
How hard was it to get the oil into the gearbox?

[mad992]

what we askin is can average joe punter aka newtriton members can we do this at home

[Longranger1]

Yes. It is easy to do, if you can do an engine oil change then you will not have any problems with this task.

You need a suction gun (to fill the gearbox and transfer case), a 24mm or 15/16" ring/open ender or socket, cotton rags and some old cardboard for a drop sheet and an oil drain dish. On the side of gearbox is 2x 24mm head diameter plugs, one drain and one level. The drain plug is on the drivers side at bottom of the gearbox and the level plug is on the passenger side roughly midway up the side of the 'box.

The transfer drain plug is on the passenger side and the level is at the back of the transfer case facing the diff. These are 24mm also. The transfer drain plug has a magnetic trap for ferrous material. Curiously, the gearbox didn't have one.

After a good run to get the oil nice and hot get under the truck (safety first here folks - use safety stands, chocks etc if needed. Those with a good suspension lift may not need to bother). Place drop sheets, clean around the level and drain plugs and use the 24mm to undo the drain and level plugs, catch oil in the drain dish (be careful the oil flows a fair way and can be quite hot). Allow to drain (say 10-15minutes).

Once drained, clean drain plug/s and reinstall - dont over tighten it is only alloy. Using the suction gun draw up the new oil and inject into the level hole/s. Repeat until oil overflows out of the level plug/s. Install the level plug bungs and you are done - a quick degrease and clean up and that's it.

[Longranger1]

The oil that I used is Penrite's recommendation - Sin Manual Trans GL-4+ 75W-85 synthetic gear oil.

Whatever Mitsubishi uses in the original fill seems to be very ordinary in quality. Those who go ahead with this will be very pleasantly surprised at the difference it makes. Feels like a completely different gearbox after the change.

[dansan]

cheers for that longranger very helpfull and will have a crack at doing that in a couple of weeks might need to get me one of those suction guns though!! thanks again..

[Trough Lolly]

good shit, ill give this a stab. only 6000kms and already my box has some rollover noise and a rooted thrust bearing & pressure plate squeek..... not happy jan!

[Longranger1]

good shit, ill give this a stab. only 6000kms and already my box has some rollover noise and a rooted thrust bearing & pressure plate squeek..... not happy jan!

Rollover noise isn't anything to get worried about and the thrust bearing squeek isn't a biggy either.

Mine only occasionally gets the release bearing squeek - more of an annoyance than a reliability issue. It is the diaphragm fingers just barely touching the release bearing face causing the noise.

The shift after the change of oil to Penrite is still baulky when very cold but I can live with that as once warm all is well.

The quicker you get rid of the original gearbox/transfer oil the better IMHO. The transfer works a lot better with the change as well. I find the transfer indicator light disengages a lot quicker too.

[Trough Lolly]

how much oil does the transfer case take to fill??

[Kegsy]

Been having troubles with my gearbox lately.

3rd can't be selected on a downshift without doing the double shuffle or rev matching. Syncro looks like it isn't playing ball.

Had drama's with 2nd gear selection a while back and added some G70 to the GB and everything was going well until now.

So I dropped the oil today and filled her up with some semi-synthetic as a trial. From the short drive I did the gearshift feel is much improved. Will have to wait till the oil warms up on a drive to see if 3rd gear syncro gets itself together. On this alone, I'd also recommend getting the factory fill VMX out asap.

Reason for trying the oil change I was thinking the syncro may have been playing up due to the G70? But thats looking really hard for a reason apart from a dodgy syncro .

If it still misses, looks like the GB may need to be pulled out if I can get the dealer to agree, last time I had troubles they palmed me off.

[Longranger1]

Yep. G70 is good stuff, but don't use it in a gearbox with marginal synchro's. Good in the tranfer and open centre diff's though.

If you flush the gearbox out a couple of times you should be ok. Try a better gearbox oil and things should improve a bit.

I've found that while using Penrite Syn Manual Trans improves things markedly, it is still baulky when cold.
A bit of patience until it warms up and all is fine I've found.

If you want to really flush the g'box well you can fill it diesel and run it with the wheels taken off and the diff sitting on axle stands i.e. absolutely no load. Works well and shouldn't harm anything if you flush with oil afterwards a couple of times. The usual disclaimers apply here, but that's what I have done in the past on other vehicles.

[Kegsy]

Yeah we'll see how it goes Pete, I doubt it will need a flush. I was running 50% of the recommended dose of G70 anyway so by the time I get to the next GB oil change & service (very soon) it should be pretty much gone.

Might try the synforce, the engine oil has been very good thus far.

[Longranger1]

In the meantime just continue to double de-clutch like an old pre-synchro cars and trucks.

It's not just Mitsubishi that has these issues, my work truck (Toyota ) is way worse than the Triton. One of the apprentices where I work has just had the gearbox changed in his BT 50 4wd at 30k.

And the DMax at work has a gearbox that has a shift that is not unlike a stick in in a bucket of mud - terrible.

[sierra]

I changed mine for that Penrite SIN Manual Trans a couple of years ago after worrying about the rumble in neutral and the original oil being similar to grey piss. It only had a few thousand on the clock and is now about 35,000km. The change is good apart from finding 4th from 5th in a bend with the weakish centering springs, touched reverse a few times with a quick change down.
I was concerned at first because Mitsubishi call for a GL-3 spec which is apparently to prevent corrosion to the metal used in the forks but Penrite said the GL-4 spec they used wouldn't be a problem.
It still rumbles a bit on idle when hot but that goes if you pick up the revs to 900rpm from 750rpm so it seems to be design fault rather than being bearings or end float?
For a gearbox designed to haul big loads it's a decent shifter and fast enough, although 1st to 2nd with a few revs needs a firm hand!

[srb]

I'm nearly due for my 7500km service and was thinking of suppling my own oils to the mechanic cause i believe there are better oils out there than the standard crap that Mitsubishi would supply. I will not be taking it to my dealer to get serviced cause they are hopeless! Would prefer to jam my dick in a door than take it there again!
Anyway i might give this Penrite stuff a go seeing longranger is so stoked with it... although i cant complain about my gear box yet, so far it's smooth sailing even when cold.
My question is to longranger... How do you get your book stamped to keep your warranty if your doing your own oil changes? I would prefer to do all the servicing myself too cause then you know it's done right, but just need to find a mechanic to stamp my book guess.

[norto]

Has anyone tried on of those gearbox additives like nulon etc

[Longranger1]

Someone on here has used Nulon G70 in their gearbox. OK in the transfer case but I wouldn't use it in the g'box.

Anything which decreases friction can cause issues with synchromesh cones - essentially it stops or reduces the ability of the synchro cones to 'pick up".

SRB. The oil changes I do are over and above Mitsubishi's requirements for servicing. I enter the details in the logbook myself and have them do servicing every 15000km's, thus honouring their requirements for minimum servicing.

[Kegsy]

Yeah that was me.

In all honesty, it improved the box.

Now that I'm back to just regular oil with no g70 I'm having more problems today.

Second gear has joined third gear now, both r.s!

Should have bought an auto lol.

[paddstar69]

hi all, you guys that are thinking about doing the oil change for your g/box, transfer or diffs my suggestion for filling the oil would be a small hand pump that is sold at auto stores (about $20) and it will screw straight onto the 2.5 ltr container, a lot less messy than a suction gun.

[Longranger1]

Yeah that was me.

In all honesty, it improved the box.

Now that I'm back to just regular oil with no g70 I'm having more problems today.

Second gear has joined third gear now, both r.s!

Should have bought an auto lol.

Doesn't look good Kegsy. Does it just baulk and not want to shift? Might be a gearbox replaced under warranty for you I'd say.

This thread reminds me of a trick used in the bad old days which mixed ATF with the gearbox oil to improve synchro function. I'm not advocating this mind you, but it did work. Probably why Mitsubishi specify a GL3 oil.

Must be a fault with these Aisin gearboxes (synchromesh) which shouldn't happen these days. I have rebuilt Mitsubishi KM132 boxes which didn't handle 300+hp very well. The gear teeth would actually metal 'flow' and then fail because of poor case hardening of the teeth. My solution was to adapt a Supra turbo box which was a lot stronger.

The Triton box seems to handle heavy loads ok as some on this forum would attest, just a pity the synchro lets its down.

[dan.batto]

Could this very well be the answer as to why when the tri isn't warmed up I have trouble getting it out of first into second and also back in to first most times??

Have now hit the 70k mark and was thinking clutch is on it's way out. This being my first manual I wouldn't know what a done clutch feels like?!

I know what an extremely old gearbox is like, my old mans 87 hilux just had it's replaced and the before and after is amazing!!

[Kegsy]

Yeah Pete. Doesn't look good at all.

As long as it holds together till I can get to the dealership I'm happy.