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2001 volvo s40 transmission fluid. Change?

Just bought 2001 s40 with 88k miles. Transmission is smooth but when I checked the dipstick the fluid color is a kind of dark. I was thinking of changing it. Here are my questions/doubts:
<br/> 1. The fluid is ATF Dexron III and Mercon oil. Right? What is the best brand to use? Castrol?
<br/> 2. As I was looking for the fluid at pep boys, i met the service manager i knew. i asked him about the transmission fluid. he mentioned to check the service record. I did not have the service record. he said if the fluid has not been changed ever, it usually got into trouble (?).
<br/> but in the haynes manual, it mentioned that:
<br/> transmission fluid does not usually need to be changed unless the car is used as taxi ( then it needs to be changed every 40k miles or so). Because of this, i think i can change it anytime. am i right?


  • edited October 2009
    Although I'm just reading this now, I would like to point out that if your transmission is running find - DO NOT touch the trans fluid!!! Secondly, the off-the-shelf trans fluids are abrasive to Volvo transmissions.

    Your transmission wears over time, and lifetime trans fluid (like the fluid in your S40) is designed to compensate for the wear. As a matter of fact, it actually utilizes the debris and grime that builds up in the trans. If you flush or change out the fluid, you then deprive the transmission. How do I know this? I went against the advice and replaced the trans fluid on my 2000 S40. About 3 or 4 months down the road, I had big problems. Lets just say it has never worked the same, and it's getting worse by the week. I am now faced with the decision to replace the trans (Volvo tranny's run about 3 or 4 grand) or get a new car.

    Even at the time I changed the fluid, every Volvo specialist I talked to said "Don't do it!!" I just thought they were full of it... it didn't make sense to me either - why NOT change the fluid? It looks dirty, right? I really hope you didn't go through with this!
  • edited October 2009

    The OP did not tell us if the trans fluid has ever been changed on this 8 year old car, but I surmise that it has not. In that case, it should definitely be changed--but NOT flushed.

    As to the preceding comment, I am going to compare that person's situation to the patient who dies on the operating table during a Quadruple Cardiac Bypass operation. That patient would have died if he did not have surgery, and was unfortunate enough to die during the surgery that was necessitated by his poor health. Both instances of death would have been as a result of him not maintaining his health properly for the preceding X number of years. In other words, that surgery may give the patient a few more years, but it cannot be counted on to overcome years of neglect of one's diet and exercise regimen.

    When the person above changed the fluid on his 2000 S40, it was likely very much overdue, and as a result, the trans would have failed anyway. This type of "Hail Mary" servicing of an older transmission rarely works.

    What does work is changing the fluid (and filter if so equipped) every 3 yrs/30k miles. People who follow that type of schedule rarely experience transmission problems. When trans fluid is not changed on that type of schedule, whether the fluid is first changed after many years of not being changed or whether the fluid is left alone, the trans is going to fail--usually anywhere between 90k miles and 140k miles. Such is the price of neglect.
  • edited October 2009
    I'm with VDCdriver on this one.

    If there is something sensitive with Volvo transmission changes, I'd welcome hearing Transman's input on it.

    While I've only rebuilt about 5 auto transmissions (and that was 30 years ago), I've never heard of a transmission utilizing the debris and grime buildup - as if it were a good thing.
  • edited October 2009
    I did change the transmission fluid; drain and refill. It only took 3.5 quarts vs 8-9 quarts the repair manual said. Most of fluid are still in the gear (?).

    I decided to change after consulting with a friend of mine who teaches auto mechanics at local college.

    so far it is ok. i used mobil one synthetics atf. I was planning to do another drain and refill again soon to clean up more of the fluid. so far, transmission is working as before if not smoother ( it may be just psycological since i changed the fluid).

    I have not checked the current fluid ( after it mixes with old ones in the gear) because i do not have time yet.

    somebody told me that if you start to have some issues with transmission, best way is to flush and refill with originial type of atf or synthetics. maybe add some additives like Xado to improve metal to metal friction. Not sure if it works.

  • edited October 2009
    Use the type of fluid recommended in the owner manual or a reputable transmission specialist. Do not use additives unless recommended by a reputable transmission specialist. Change the fluid every 40K as outlined by the severe service recommendations. You could not drain most of the fluid via the pan because most of the fluid is in the torque converter.
  • edited October 2009
    It is OK that your drain-and-refill only takes 3.5 quarts while the whole transmission takes much more. If you do that every 30k-40k you'll be fine.
  • edited October 2009
    Here is more explanation on why some do not recommend changing transmission oil.

    my guy ( who is teaching auto mechanics at local community college) explains as follows:

    1) atf oil is lubrication but the enemy is heat.
    2) when it is overheat, atf oil breaksdown and did not really function
    3) but when transmission shifts, there is "disk" to move it ( i do not really sure ), and this one will expand as atf oil brake. so it is like to compensate
    4) thus, in old one, when we flush with new oil, the "disk" will shink back and causing some issue.

    5) thus, if it does happen, the tranmission failure is just waiting to happen anyway.

    i will drain and fill every 20-30k miles since i do it myself the atf cost is minimal.

  • edited October 2009
    I know you're only passing along the input that your mechanic is telling you, but there is little hope of trying to convince anyone on this forum on reasons why transmission fluid should not be changed.
This discussion has been closed.