Auto issues. Giive me tips before I start

[denmonkey]

Hi all,



I've been gradually having issues with my auto but hadn't quite realised it until this weekend out on the tracks with the boys.
With it becoming painfully obvious there was an issue, looking back I can pick a few times where it presented itself but I just put it down to other things.

Notably I've felt like I've dropped in power, in particular on hills etc.

This weekend, i was heading up a steapish hill in hlc and stopped.

When I attempted to accelerate it would barely moved up the hill, just sitting on about 2k revs and just creeping along.

I had to go to low range to get it to move. This might point to the transfer box. Had something similar with a delica.

It also died in the arse heading up a sand dune 2 weeks ago.

Took 3 attempts to make it where I had walked up previously.

I just couldn't get it up to speed before hitting the bottom and it slowed terribly when climbing.


Further on, we were climbing some steep black top and I could not get it to accelerate up to speed. A few spots, I thought it was going to stop dead.

This was in 47 degree heat.


If I babied the throttle, it would gain speed in first but then die in the arse when it hit second and I'd have to go back to first.

If we'd stop and let it cool for under 10 minutes, it would run fine but go back to the same issue again once it heated up again.

This makes me thing its the auto and fluid related and not mechanical.



Even on joining the freeway, I have to pick my gap because it can take nearly a minute to accelerate to 100kms with light throttle.

If I pin it, it wont accelerate and can be dangerous.

It made for an interesting trip back to Newcastle today in the heat from port macquarie.

I'm so glad I didn't have the van in tow.



So in short:-

Nt Model

Car has 205k on the clock ( had it for around 15k)

Services have been kept up. Nothing on a trans fluid change as far as I can tell

won't accelerate normally when warm/hot . worse when very hot ( so temp related)

runs normal when cool

hold gears longer than it should . changes are still smooth enough though other than being at the wrong revs to where it would normally change up.

ok in low range but still think the issue is noticeable but not as much.

Hills are obviously where it really struggles


No smells are evident


no mechanical sounds or any other symptoms to note


shifting in and out of drive /reverse etc work as they should


Monitored temps on road/hills see it sitting at normal temps between 75-90.

Revs do NOT climb when trying to accelerate like I would expect with slipping. Just bogs down.


Cruises ok at speed, so long as not trying to accelerate hard.


With all that in mind, I'm thinking its the tranny and it needs a fluid change/service.


Needless to say, I'm taking it in this week as soon as I can for a service and hoping a simple change of fluid etc might sort it out.



My questions


Have you had this issue and what was the result ?



Who has had a service/flush etc and whats the ball park cost ?



Did they use the specific Mits fluids ?



Who has tried no Mitsu fluids ?

I'm considering a bigger Trans cooler. Anyone done it, cost, source etc would be handy ?

Any others tips are appreciated.



Cheers Brett

[Hill]

Bret

Any engine related any engine codes/light.
Could be vacuum leak in engine as engine is not revving out.
Had something similar in my NT a few weeks ago.
Turned out to be vacuum line on drivers side rubbed itself through.

Check for codes.

Hill

[old Jack]

Agree with Hill that it may not be 100% related to the Auto Trans.

ATF service life on the NT/NW/NX with the "non-dipstick" Aisin trans is 195,000km, from memory, unless it is operating in "severe conditions" like off road, towing, stop/start traffic, in which case I believe it is around the 100,000km service life, check your Service Handbook.

Forget about a 2nd ATF cooler, just stop the ATF from getting hot in the first place!
Torque Convertor lockup kit will do this, there are multiple available but in my opinion the MM4x4 Lockup Mate or Auto Mate are the best as they were specifically developed and built for Pajero/Challenger/Triton by forum member m-&-m.


OJ.

[Keithyv]

Sounds to me the transmission is getting severely overheated.
Just my guess & 2c worth..

[old Jack]

Sounds to me the transmission is getting severely overheated.
Just my guess & 2c worth..

"The ATF Over Temp" warning light on the dash display comes ON at 147C and OFF at 127C.
At these temperatures you have already shortened the life of the ATF.


OJ.

[kiwi1973]

Whether your issues are auto related or not, seems like you are (over)due a change in ATF fluid anyway, so no harm starting there. But get set up with some means of reading your ATF temps - Android Torque is good.

Doesn't have to be Mitsi fluid so long as the fluid used carries the the appropriate specs from a reliable brand like Castrol or Penrite.

If you're not doing this job yourself make sure to go to somewhere where the job will be done right - full flush. Too many places will happily charge you to replace the little bit of fluid that's in the pan. Not really essential to replace the strainer in the pan. Flush is the main point.

[Kingbrown]

Sounds to me like the engine isn't coming on song.

Are filters (fuel and air) ok ?
What boost readings are you seeing ?

[denmonkey]

Thanks all for your input.

No warning lights on the dash and trans temps on normal freeway have been within spec.
I really should have had torque on when the issue were at their worst .

Hill, I don't think it's a vacuum issue as it seems to only occur when the engine it hot.
I'd expect a vacuum issue to be present at all tempts. I won't rule it out though and will keep it in mind if the transmission checks come back all clear.

OJ, I was planning on getting the lock up kit in the next few weeks and then this turned up.
No point until I can get it sorted. It's still on the list though.
No warning lights re trans temps...which I figure is good.

Kiwi, yes, I think you're right. I'll get it done anyway . I'm towing and doing a bit of off road, so it's worth the effort.

I spoke to the trans specialists and they seem to think its auto related but will be taking it on Friday for the to test drive it.
They said about $500 with full flush and I believe Castrol fluids to spec.
extra charge for having to drop the cross member to access.
Could be done cheaper without full flush but I told them I want the full flush.
Thus the higher cost.


KB, it does feel like that but runs fine when cooler or even after a few minutes breather.
I'm not 100% on the trans but I'm about 95% I reckon.
All filters etc had been done less than about 3000kms ago.
Will be dropping the fuel filter to look just in case.

thanks again fellas for the input.
Gives me confidence in the non mitsu fluids.
I'll be sure to report back with an outcome

cheers Brett

[denmonkey]

Hi all,



just wanted to report back on the fix for my issue.

Nothing shits me more when people drop in for advice and then never report back on how they solved their problem .



I took the Nt into the trans specialist and he didn't think my issue was trans related.

Still booked in for monday for a service and full flush anyway.



On more reading and following on from Hill's advice, I looked into the vacuum hoses as the possible culprit.



The more research I did, the more it seemed like this could be the issue.



With a quick trip to super cheap for 10 bucks worth of hose (2m) and about half hour under the bonnet and a clean of the MAF sensor, the old girl is back to full power.



Whilst under there I also removed all of the electrical connections I could easily reach and hit them with some contact cleaner just to be sure.



The MAF sensor was pretty dirty but I'm confident the hoses were the issue.



A few of the broke off when trying to disconnect them, so they were very brittle.

I didn't notice any holes etc but I reckon this was it.



Which one ? I don't know.


I replaced them all except the ones going to the solenoid for the front hubs.

I will be doing those soon though as its 5 minutes work and probably another 5 bucks of hose.

Well worth the effort.

That said, the front hubs are now locking and unlocking a lot quicker.
Not that there was a particular issue there but they had begun to take a bit more time to switch and I can see they share the vacuum circuit on the drivers side of the engine bay.



thanks to everyone who offered advice.



My advice to anyone having power issues, it tackle the hoses first. For such a low price and a small about of time, it's well worth ruling out.



If this didn't fix it, the next things to look at were the sensors. They apparently can cause the same issues.





thanks again

[aussieintas]

Hey bud thanks for getting back with the fix. Can I ask what size hose did you get, thinking about renewing mine.

[denmonkey]

I knew someone was going to ask that
No mate, I don't .



I just matched the one off the MAP sensor that goes down to the engine .

You'll see it as it is attached to the other side of fuel filter bracket .

They had 2 sizes that looked to be a match so I grabbed 2 meters of both. both are about 5 bucks a meter.

The one with the larger internal diameter was the one which fitted.

It fitted everything I changed over.



I still have some left over and will grab the OD for ya this weekend and report back.



cheers Brett

[aussieintas]

All good bud, I'll do same a grab both or the closest.

[Kingbrown]

Good to hear it was a straightforward (and cheap) fix, albeit with some head scratching along the way.

The sensitivity to temperature is puzzling.
Softening of vacuum hose(s) which allowed air to enter the system through defects maybe ?

[old Jack]

Good to hear it was a straightforward (and cheap) fix, albeit with some head scratching along the way.

The sensitivity to temperature is puzzling.
Softening of vacuum hose(s) which allowed air to enter the system through defects maybe ?

My money is on a dirty #1 Air Intake Temperature sensor which is a thermistor incorporated into the MAF sensor, a dirty thermistor, combined with high ambient temperatures could mean the engine ECU was getting an incorrect extreme pre intercooler intake temperature signals and then the engine ECU was going into self protection mode.
Good preventive maintenance replacing the vacuum hoses and getting the auto trans serviced.

OJ.

[denmonkey]

Thanks boys.

It's not often you get a cheap win like this, so I'm enjoying it for all its worth.

The temp thing was what convinced me it wasn't the hoses, especially with the improvement after a quick cool down.
plus the transmission dong weird things, it made sense to look at that first.
I guess the sensors relying on the correct vacuum were sending odd messages to the ECU and in turn that was confusing the auto.

I noticed there were some additional sections underneath near the trans when taking off the bash plates last night.
Will suss out what they are and do them as well. I think they're something to do with the 4wd system, but not sure.

Knowing how simple a job it is and cheap, I'll probably do this every few years as part of a maintenance routine.
Plus a length of hose will be going in the always in the car spares kit.

Does anyone know if there is an external hose for the rear diff lock ?


Thanks again for the input all.