NM 3.5L V6 difficulty shifting & going into gear

[lostproperty]

Hey everyone.

I have done a search and found a fair few threads from people who have has problems going into gear but unfortunately none of those posts except for 1 had an outcome (the outcome of that post was a replacement clutch and DMF to single flywheel - which doesn't really apply here as I have a petrol model which I believe is a single fly wheel from factory but please correct me if I am wrong)

Background: Car has 117xxxkms on it, purchased it recently and have replaced all the gear oil plus timing belt & replaced clutch slave cylinder & fully bled the system which hasn't improved anything. The car looks like it has done some light off road and beach work in its previous life. Has sat for about 7 years without really been driven before I purchased. Bought from a wholesaler after the car was traded in so unfortunately didn't have an opportunity to speak to the original owner.

Symptoms: The gears were slightly notchy when I got the car so I asked my mechanic to change the gearbox oil and also put in a nulon treatment as this has helped my gearboxes in the past when they have been sticky. When my mechanic changed the gearbox oil the difficulty going into gear was worse than before he changed it, it was noticeable before but now its to the point where it barely goes into gear and its worse when it's cold.

When the car is off it goes in and out of gear with ease and the gearbox feels smooth. There isn't any whine coming from the transmission.

From my basic mechanical knowledge I've put it down to either being the clutch, or there is an issue with the gearbox itself.

Weirdly when I was sitting idle for a long time I almost felt a bit of a "click" or something similar while I was trying to shift in and out of gears while I was waiting for a parking spot and suddenly the gears were shifting very easily with the clutch in and I went through every gear without any issue at all. I then took my foot off the clutch and again it went back to being hard to shift into gear again and didn't revert back to the "easy shift" I had momentarily experienced.

Has anyone had any similar experiences like this? Most quotes in Sydney for a new clutch are around $2500 mark give or take depending where it is so wanted kinda prepare myself for it before taking it in. Would it be worth running the Castrol Mitsu gear oil 75w85 just in case? I think the mechanic put in 80w90.

Thanks team!

[erad]

Hey everyone.

I have done a search and found a fair few threads from people who have has problems going into gear but unfortunately none of those posts except for 1 had an outcome (the outcome of that post was a replacement clutch and DMF to single flywheel - which doesn't really apply here as I have a petrol model which I believe is a single fly wheel from factory but please correct me if I am wrong)

Background: Car has 117xxxkms on it, purchased it recently and have replaced all the gear oil plus timing belt & replaced clutch slave cylinder & fully bled the system which hasn't improved anything. The car looks like it has done some light off road and beach work in its previous life. Has sat for about 7 years without really been driven before I purchased. Bought from a wholesaler after the car was traded in so unfortunately didn't have an opportunity to speak to the original owner.

Symptoms: The gears were slightly notchy when I got the car so I asked my mechanic to change the gearbox oil and also put in a nulon treatment as this has helped my gearboxes in the past when they have been sticky. When my mechanic changed the gearbox oil the difficulty going into gear was worse than before he changed it, it was noticeable before but now its to the point where it barely goes into gear and its worse when it's cold.

When the car is off it goes in and out of gear with ease and the gearbox feels smooth. There isn't any whine coming from the transmission.

From my basic mechanical knowledge I've put it down to either being the clutch, or there is an issue with the gearbox itself.

Weirdly when I was sitting idle for a long time I almost felt a bit of a "click" or something similar while I was trying to shift in and out of gears while I was waiting for a parking spot and suddenly the gears were shifting very easily with the clutch in and I went through every gear without any issue at all. I then took my foot off the clutch and again it went back to being hard to shift into gear again and didn't revert back to the "easy shift" I had momentarily experienced.

Has anyone had any similar experiences like this? Most quotes in Sydney for a new clutch are around $2500 mark give or take depending where it is so wanted kinda prepare myself for it before taking it in. Would it be worth running the Castrol Mitsu gear oil 75w85 just in case? I think the mechanic put in 80w90.

Thanks team!

You may possibly have the clutch not fully disengaging as you push the pedal down. Possible causes for this are a sticky clutchplate on the input shaft or maybe a spongy hydraulic system. The latter is easy to check - get someone to bleed your clutch - the same as the brakes. Have an assistant push the pedal to the floor and hold it while you crack the bleed screw on the slave cylinder (next to the bell housing a head of the gearbox. Tighten the bleed screw and then tell them to lift their foot and repeat the process. Make sure that the bleed screw it tight BEFORE they lift their foot, or you will get a gutful of air into the cylinder. You will probably find that the clutch hydraulic fluid has never been changed and you may even have corrosion or sludge inside the cylinder which is stopping the clutch from releasing properly.

[lostproperty]

You may possibly have the clutch not fully disengaging as you push the pedal down. Possible causes for this are a sticky clutchplate on the input shaft or maybe a spongy hydraulic system. The latter is easy to check - get someone to bleed your clutch - the same as the brakes. Have an assistant push the pedal to the floor and hold it while you crack the bleed screw on the slave cylinder (next to the bell housing a head of the gearbox. Tighten the bleed screw and then tell them to lift their foot and repeat the process. Make sure that the bleed screw it tight BEFORE they lift their foot, or you will get a gutful of air into the cylinder. You will probably find that the clutch hydraulic fluid has never been changed and you may even have corrosion or sludge inside the cylinder which is stopping the clutch from releasing properly.

Apologies I thought I wrote this in the post, I've bled the clutch and also replaced the slave cylinder already which didnt improve things. Pedal feels better with a new slave cylinder than before but the engagement is still the same

[Crocodile]

Hello Lostproperty,


when you select reverse with the motor idling, do the gears crunch?


If not, it means that the clutch is not dis-engaging correctly.

[erad]

I thought of the same diagnosis trick, except that the Pajeros have synchromesh on all gears (including reverse), so this diagnosis trick may not work.

[lostproperty]

Hello Lostproperty,


when you select reverse with the motor idling, do the gears crunch?


If not, it means that the clutch is not dis-engaging correctly.

It doesnt crunch in any gears, which is why I was thinking it wouldnt be a syncro issue. I've completely blown a 2nd gear syncro in a corolla gearbox before and know what it feels like.

Changing the clutch master today and if that doesn't work then it's off to a clutch specialist on Monday he wants to see if it needs adjusting before changing it so I like the fact he doesnt just want to throw a new one in there especially because it isn't slipping.

[erad]

In a case such as this, there are 3 possible causes.

1 The clutch is not travelling enough and is still partially engaged and the synchros are baulking the gear change. Or

2 The clutch plate is sticking on the gearbox input shaft, not allowing full travel and therefore the clutch is still trying to drive the vehicle. Or

3 The selector mechanism bushes are worn and maybe you are trying to engage two forks at once.


Number 1 option you say you have checked out, but this is the most likely cause. Especially if the clutch slave cylinder was not properly bled.

Number 2 option is unlikely unless you have been in water and the drive shaft splines have gone rusty. This symptom will probably reduce as the engine and shaft warm up and will probably be worse when everything is cold.


Number 3 option is the easiest to check. Try wiggling the gear stick sideways and back ad forth and see if the change is any easier. This is a probable cause and there have been a few posts on this forum about worn gearstick bushes.

Re taking the beast to a clutch specialist, there is no adjustment to be made on these clutches other than the pedal free play.

[chippy4x4]

Just curious, how many kms have you travelled in the car since you have owned it? Just thinking that if you have not been far and the car has been sitting for long periods, then things have been known to "stick". I had a car that had sat around for over 4 years and the gear change was "sticky". However after a long drive of over 5 hours everything start to come good as all of the drive train had heated up and appeared to have freed things.
just a thought anyway

[lostproperty]

In a case such as this, there are 3 possible causes.

1 The clutch is not travelling enough and is still partially engaged and the synchros are baulking the gear change. Or

2 The clutch plate is sticking on the gearbox input shaft, not allowing full travel and therefore the clutch is still trying to drive the vehicle. Or

3 The selector mechanism bushes are worn and maybe you are trying to engage two forks at once.


Number 1 option you say you have checked out, but this is the most likely cause. Especially if the clutch slave cylinder was not properly bled.

Number 2 option is unlikely unless you have been in water and the drive shaft splines have gone rusty. This symptom will probably reduce as the engine and shaft warm up and will probably be worse when everything is cold.


Number 3 option is the easiest to check. Try wiggling the gear stick sideways and back ad forth and see if the change is any easier. This is a probable cause and there have been a few posts on this forum about worn gearstick bushes.

Re taking the beast to a clutch specialist, there is no adjustment to be made on these clutches other than the pedal free play.

Number 2 sounds the most familiar in symptoms and it does improve after warming up and driving. The car was sitting for about 7 years with limited use. Is the only way to fix this but changing to clutch? I'm worried if I keep driving it then it'll end up causing damage to the gearbox

[lostproperty]

Just curious, how many kms have you travelled in the car since you have owned it? Just thinking that if you have not been far and the car has been sitting for long periods, then things have been known to "stick". I had a car that had sat around for over 4 years and the gear change was "sticky". However after a long drive of over 5 hours everything start to come good as all of the drive train had heated up and appeared to have freed things.
just a thought anyway

I've done about 1000kms since I've owned it mainly because its spent most of its time in workshops having things fixed on it. But it is also quite hard to drive it when it is cold so I have been avoiding using the car and have been driving my other car on a day to day basis instead. Took it on the freeway for a good trip from sydney to barrington tops after it was serviced straight after buying it but since then when its been cold it has become progressively more difficult to get into gear. It definitely didnt have any issues when I test drove it and bought it, the car was definitely cold when I first checked it out, it was on a ramp and definitely hadn't been "Warmed up" before I got there. Same story with when I went back and picked up the car and drove it home.

I changed the clutch master as well and have dropped it off at a different mechanic as my guy is too busy to fit it in and didn't really have any ideas on what it could be anyway despite having the car for 4 days, so we'll see if he can try and make some adjustments or properly diagnose what is wrong. Just a little frustrating at the moment as everyone is "too busy" to try and work it out, or can't give me an idea on what it is when looking at it

[nj swb]

When the gearbox fluid was replaced, what was put in?

I don't know about the NM, but Castrol developed a gearbox oil specifically for Mitsubishi synchros, and is strongly recommended for the Gen 2s - VMX-M (M for Mitsubishi). With the wrong oil the synchros don't work properly, and the box is notchy - particularly when cold.

Personally, I'd take it for a good long drive (get it nice & warm), somewhere twisty that needs lots of gear changes, give the fresh oil a chance to work out any crud that might've accumulated during all those idle years. Then drain the oil again, and make sure it's filled with VMX-M, and treated with Nulon G70.

[erad]

The problem, as I see it, is that the clutch is not properly disengaging to allow clean gear changes. The gearbox oil should not affect this, although it may cause crunching of the gears as they change if the synchros are not working the way they were designed.

You say the car sat for 7 years. It sounds as if the shaft on which the clutch plate slide may be rusty. If this is the case, the best way is to pull the gearbox and clean it up, but that is a lot of work. just using the car a lot ie lots of clutch working in and out will probably free it up.

[lostproperty]

When the gearbox fluid was replaced, what was put in?

I don't know about the NM, but Castrol developed a gearbox oil specifically for Mitsubishi synchros, and is strongly recommended for the Gen 2s - VMX-M (M for Mitsubishi). With the wrong oil the synchros don't work properly, and the box is notchy - particularly when cold.

Personally, I'd take it for a good long drive (get it nice & warm), somewhere twisty that needs lots of gear changes, give the fresh oil a chance to work out any crud that might've accumulated during all those idle years. Then drain the oil again, and make sure it's filled with VMX-M, and treated with Nulon G70.

Gearoil was replaced a few weeks ago with 75w85 penrite and with the nulon g70 as well. I'll keep on drving it and see if it gets any better. If not I'll change the oil again for the castrol VMX-M and add in the nulon g70.

[lostproperty]

The problem, as I see it, is that the clutch is not properly disengaging to allow clean gear changes. The gearbox oil should not affect this, although it may cause crunching of the gears as they change if the synchros are not working the way they were designed.

You say the car sat for 7 years. It sounds as if the shaft on which the clutch plate slide may be rusty. If this is the case, the best way is to pull the gearbox and clean it up, but that is a lot of work. just using the car a lot ie lots of clutch working in and out will probably free it up.

Thanks mate I'll keep driving it and see how it goes. It'll be interesting to see what the grumpy clutch mechanic says this afternoon when I get the car back, either way I will definitely post up the outcome.

[erad]

"Grumpy" typically means expensive. In a way, I cannot blame him because they are a very heavy gearbox if you have to remove them. Hopefully it will ease up with use.

There is a hatch cover in the bell housing. Maybe you could have a look in there and see if the shaft is rusty or dirty. It would be nice to squirt some WD40 up there, but I think it would not go where it was really needed and may do some damage in the process.