Auto Transmission fluid flush
Hi Guys,
This could be one of the most stupid questions asked on this forum.
I’m trying to do an AT fluid flush as part of my next service on my Pajero io 1.8 GDI, SWB vehicle.
Believe it or not, this is the first ever auto transmission vehicle I’ve owned. I have always been a manual guy.
Everything seems straight forward on the service manual accept for locating the oil filler tube. Is that referring to the transmission deep stick tube or the return hose from the bottom of the radiator?
Also, many auto transmission vehicle owners are saying you shouldn’t flush your AT fluid on an old vehicle. Your transmission could slip. I know where they are coming from but I refuse to believe that for my case simply because my transmission fluid, from the deep stick is just starting to turn dark reddish and doesn’t have that burning smell yet. I do not intend to keep it until it turns black
I imported my vehicle from Japan as a used car. It’s a 1999 model with 49,000 KM on the ODO when I got it. It now just clocked 70,000 KM and it’s a year now. The only service history it came with was oil changes. I did check the transmission fluid when I first got it and it was very clean. So I would assume it was serviced prior to it being sold.
What are other components that need attention when doing a regular service on the auto transmission
I don't know if there's such a thing as a stupid question ...
if there is, I've asked more than my fair share, but there certainly is such a thing as a stupid answer.
First up - the reason why people will tell you not to flush a transmission is that there is a lot of experience out there that has shown that a transmission will often fail shortly after being flushed - what is lacking is the investigation and analysis as to what actually caused the failure, there are many possible reasons, one of which is that dirt that gets "stirred" up can block the passages in the valve body, another is that the old, "dirty" fluid is really a thick "soup" of friction particles dislodged from the clutches & brakes that are in the transmission, and if this "soup" is replaced, there is less friction material so the transmission slips.
Both of these theories neglect to address the key issue - if either one is true, the real problem is not the fluid flush, but the previous neglect of the transmission - how many transmissions are not properly serviced and only get attention when there is an issue, so step one becomes a flush, and step two is replacement, which gets blamed on the flush, despite the fact that the problem started before the flush.
Now to the original question - if you're following the procedure in the service manual - I wouldn't consider that flushing the transmission, it's more of a drain & refill, and is no more dangerous, from a "dirt blocking port" view than driving the vehicle, the only thing that gets flushed is the cooler tubes.
I'm not certain why you would be asking about that question about the filler tube, when I look at the procedure, the only time I see the filler tube mentioned is to add fresh fluid.
I have used this procedure to replace the fluid in my transmission, I will admit that prior to doing it I read the "horror stories" on the internet, and I was hesitant, especially because the fluid in my car was very dark, almost black (no burnt smell), and the service history was unknown - I decided to take the chance and have no regrets. If I were in your position, based on the details you've provided, I would have no hesitation.
Thanks FORDEM, Is this the
Thanks FORDEM,
Is this the procedure you followed? If thats it, the only question I have is the location of the yellow highlight.
The summary of my procedure would be ;
1. Drain fluid from transmission pan (via drain plug)
2. Drain from torque converter and fluid lines (by disconnecting the hose that carries fluid to the cooler and running the engine for a short time)
3. Refill new fluid via oil filler tube (I'm not sure where that is)
4. Repeat step 2 and three until clean fluid comes out.
Now I understand your dilemma...
The oil filler tube on most automatics, this one included, is the transmission dipstick tube - you'll find it near the firewall between the engine cover and the brake master cylinder. There's a little latch that holds the dipstick in, pull it back, pull the dipstick out, insert your funnel and slowly pour the fluid in - they do make specal funnels for this application, with a long narrow spout.
Yes - that is the procedure I followed.
Thanks guys
Thanks FORDEM,
I assumed that would be it. Just needed confirmation from people who have done it before and know what they are talking about.
Claude io, that is somthing I will be watching very closely. Thanks for the caution. I will be carefully doing this since it will be my first auto tranny service.
signing up on this site is one of the best things I've done. There are tonnes of valuable information as well as resources and advises based on experiances here.
Where I'm from, there is only one mitsubishi dealer. If you think their charge on OEM parts are exorbitant , you will fall over when you see their labour cost, even for a simple oil change. Besides them, there are cheap chinese aftermarket part dearlers, who sell parts that dont last over a year.
Thats why I order my parts (even belts and spark plugs) from sites like mega zip, partsouq, amayama..etc. (I'm deviating from the subject. I better stop)
So yes, thanks for taking the time to answer my queries, even if its as simple as confirming the location of the oil fillier tube.
I do have other modification queries such as installaing a seperate transmission cooler, installating a ctach can, blanking the EGR but I will post later on the appropriate forume.
Cheers guys.
This is also the first auto transmission vehicle I've owned ...
In some ways we are similar, my iO was the first automatic transmission vehicle I owned, and so the first that I've been doing maintenance on.
The first time I pulled the fault codes from the transmission controller I was horrified at the number of faults logged, and quite puzzled because the transmission appeared to be working well - I subsequently discovered that a previous owner had had a run-in with a dog that made a mess of the wiring harness under the truck, it had been repaired, but the codes were never cleared.
The service history was unknown, the fluid was black, so, with a great deal of anxiety & hesitation, I did a fluid change, and have since added a temperature guage with the sensor in the line to the cooler, so that I could see what the transmission temps were like..
It's not a bad idea to have a transmission temp guage, especially if you're going to be running in sand or mud, but, strictly speaking, not really necessary - the iO has a temp sensor and will flash the neutral light if the fluid temps become excessive, and based on what I've seen with the gauge, the factory cooling is more than adequate for normal use on paved roads, so unless you're towing or getting into serious off road usage, you probably don't need an external cooler.
EGR blanking is as simple as cutting an oval stainless steel shim and inserting it where the EGR pipe attaches to the throttle body - there are no regulations preventing me from doing it, you need to be aware of what of the requirements in your neck of the woods - I haven't bothered with a catch can at this time, I probably have more oil passing the rings that I do through the PCV system - a long over due rebuild will hopefully happen this year.
Syndicate
Surely clean fluid is better
Surely clean fluid is better than dirty fluid, just can't see the engineering logic of keeping dirty fluid in the transmission, until it fails?!