I have a S60 t5 that drives fine in auto till second gear but wont shift into third but if you put it into tiptronic mode it does shift into third and forth and up. I've had it at mechanics that say a transmission oil and filter change will solve the problem . But I'm doubtful . Do any of you maybe have any input .

 

A transmission fluid flush or drain and fills might help - be sure the correct fluid is used and nothing else. Trans fluid level is critical also - and it's difficult to get to the dipstick.

There is no filter. Trans and valve body problems are common in that transmission and that basic trans is used in many brands of cars - so the problems are well known.

Google volvo slam shifts for ideas.

Ideas for changing the fluid can by found by googling "the gibbons method" .

 

So in your opinion. There is nothing mechanically or electrically wrong with the gearbox.
Do you think anything other than the oil needs to be replaced?

And one more thing , According to google I should use Dexron III but I've been told to use Dexron VI because its better . Is this correct ?

 

No- just the opposite, there is something wrong with your gearbox. Could be a worn valve body, solenoid problems or many other things - It's 21 years old. . Fresh correct fluid MIGHT help.

Fluid - JWS3309, Type IV Toyota, Aisin (the trans manufacturer) type T-IV, Volvo 1161540 - I don't think or have not heard of a "Dexron" fluid that is compatible. Dexron fluid is used in the 2003 - 2006 xc90T6 with the GM trans and T6 engine (and some other older Volvos, but NOT in the Aisin 5 speed transmission)

 

Do you maybe have an idea on why if in tiptronic mode it switches fine ?