My 07 Outie has 110K miles on it and I just had some preventative maintenance performed that was a bit overdue. The factory manual calls for transmission fluid replacement at 45K miles and every 45K after that if I remember correctly. I did it myself at 45K and the transmission did seem to shift better after that fluid change. I did not get to it at 90K and have noticed rougher shifting and some mild shuddering at times during upshifts. I finally did the fluid and filter replacement last week and boy, what a difference. The shifting is dramatically improved and it almost feels new again. If any of you are thinking about skipping this service because the cost of fluid is too high, don't. It makes a noticeable difference and I am sure it will prolong the life of the transmission. I am very happy I did not put this off any longer.

I performed the full fluid replacement that involves pulling one of the lines going from the transmission to the oil cooler in the radiator and running the engine for about 90 seconds to pump out all of the fluid. Some dealers and service ships will only drain the pan and replace the 3 liters that is in there. This is not what you want to do if you like your Outie and intend to keep it a long time. There is another 5 liters in the rest of the transmission and the only way to get it out is described in the factory manual.

If you have a newer Outie and are considering skipping the first fluid change at 45K, don't. Otherwise, it will be too late to correct the damage that will accrue as you approach 100K miles. One of the best features of these cars is the automatic tranny. It is well matched to our engines and vehicle size and weight. I am sure it is also very expensive to replace.

 

I'll 2nd that!

 

Hi mda185,

can you tell me where is the filter? I do not recall being mentioned in the manual. Are you the part number for the filter?

I just replace the tranny oil but not the filter . . .

 

To be honest, I don't recall changing the filter at 45,000 miles when I did the service. I paid the dealer to do it at 110,000 miles because he was already giving me a pretty good price to change the timing belt. I DIY most of my work but the timing belt and tranny fluid change came due while I was in middle of swapping engine and transmission from BMW M3 into a 95 BMW 525i station wagon. Wife drives the Outie most of the time and this was winter season. I did not want to put off critical maintenance. Dealer told me there was a filter at bottom of transmission that should be changed at 110K if it was original one. I told him go ahead and do it. I got timing belt, water pump, transmission service, spark plugs, transfer case fluid change, and rear diff fluid change all done at same time for $980. That is a very good price for dealership work in NJ. Even if he was wrong about transmission filter, I am not upset about it. The car came back running and shifting like new again and the improvement was very noticeable.

So bottom line is I am not sure if there is a filter at bottom of transmission. I bet there is a wire mesh screen at the bottom of the oil pick up tube and maybe this is what dealer was referring to. Either way, I am not concerned about it. If you have changed the fluid, you are way ahead of the game. Most folks these days don't bother to service their auto transmissions and wonder why they break at high mileage. The improvement in how mine shifted with new fluid is enough to convince me to do the service.

 

So are you saying that the dealerships don't do a full transmission fluid change? I've had it done at the interval in my manual (I am in canada BTW) and assumed they did a proper full change. That's not cool....

 

for the regular automatics, they do not. if you press them, they only do a drain & fill.

when I bought my fluid for a full change, it cost $130. I had them do the service the first time, cost me $140. they charge $80/hr labor. That doesn't leave much for fluid cost.

 

So a drain and fill is what they do in their scheduled maintenance (thus only getting about 4L of new fluid in there). IN our manual, transmission fluid gets changed 48,000KM, and 96,000KM, and I don't know what after that. Not doing a COMPLETE exchange shouldn't be detrimental should it? If it was , wouldn't that be in the manual?

 

Well, this just brings up some pessimism in me. If the manual says change the fluid, to me, that means change all the fluid. I'm sure you could do a drain & fill every 20k miles or so and you'd be adding enough new fluid that you'd probably be okay. It seems that they want you to keep changing it every 48km, which is probably a conservative number anyway to keep the lawyers off of them. My stealership said they recommend every 45k miles / 73KM. I'm sticking to that schedule. They way my wife drives, she's skirting the boundary of regular/severe.

 

I just talked with the dealer. THey charge $17/L for transmission fluid and said it holds about 12L. That's $204 + one hours labor so you are looking at about $300.

Mind you, he said it would be worth it to do outside the warranty period. So that just makes me wonder if any damage is being done for the first 160,000KM as this is the warranty period.

I guess bottom line question is this....Is damage being done by NOT doing a 100% complete exchange of the transmission fluid, when 4L or so is being drained every 48,000KM (30,000miles)?

thanks for your input. I would do this at home in a second if I had someone that knew how to do it.

 

You should change all the fluid each time. I did the labor myself the first time at 45K miles and it was not too difficult - just messy. Leaving approximately half the old fluid in is never a good idea. Part of its job is trap and hold dirt and contaminents in suspension. I don't understand why dealers only change what they can drain with engine off unless it is because they know there is more profit in selling a rebuilt transmission or new car when the tranny eventually fails. Change all the fluid at 45K mileage intervals and the tranny will probably never fail. Changing half the fluid each time is probably good enough for leased vehicles and ones that get traded in every 3 years. The poor soul that gets stuck with a failed transmission will not be the original buyer.

I am an old school mechanic that learned most of what I know in the 1970's and 80's. Modern automatic transmissions run higher internal temps and pressures than the old tech automatics of that time period. Back then, we recommended changing fluids every 30K. Synthetic oils help with the harsher operating conditions but regular fluid changes should still be done if you want your vehicle to last a long time. Manufacturers don't want to say that because they are probably afraid it will hurt sales. In an era where many buyers choose to lease and get a new vehicle every 3 years, it does not matter to that first owner if good preventative maintenance is practiced. The cost of recommended preventative maintenance will probably hurt sales unless the buyer is knowledgeable enough to understand all cars should be maintained this way. Most manufacturers do not have your best interests in mind when they make maintenance recommendations these days. Profit margins and repeat sales from planned obsolescence is in their best interest. Mitsubishi should be commended for actually specifying complete fluid changes every 45K miles.

My local dealer did not admit any of this to me but the service manager did agree to change all the fluid and charge me an hour labor + tranny fluid cost. Not all dealers will be this accomodating but mine was. $17 per liter is a hefty markup. I only paid $12 per liter at my dealer.

Bottom line is the transmission shift quality improved dramatically each time I changed or had the dealer change all the fluid. That is all.