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Matt, Engineer
Category: Volvo
Satisfied Customers: 21988
Experience:  Mechanical Engineer with 20 years experience in the auto industry, 8 yrs in formula 1 engine testing
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2004 Volvo S60 2.5T - Started to notice occasional hard

Customer Question

2004 Volvo S60 2.5T -
Started to notice occasional hard shifting from 2nd to 3rd and downshifting 3rd to 2nd (specially on uphill for some reason).
finally a couple of days ago, while the external temp was about 100 deg and on an uphill, the downshifting from 3rd to 2nd jerked the car and I had to stop.
as a result :
1- the Check Engine light came on
2- the red triangle with exclamation mark turned on
3- message says: Transmission Maintenance Required
I drove back home for 150 miles and the car shifted properly with no noticeable issues.
took it for a reading and the codes are : PO 700 (transmission control system) and PO 740 (Torque converter clutch).
Had it inspected by 2 mechanics but the difference in diagnostics (and price) was too steep that I wanted to get some opinions here
they will both charge me to open up the gearbox but one of them was adamant that it will be between $2,400 to $3,800.
the second mechanic said that it could be a sensor or less expensive repair but if he sees a lot of metal then it will indicate that a rebuild is needed.
thanks for your help!
Submitted: 2 years ago.
Category: Volvo
Expert:  Matt replied 2 years ago.


OK to launch straight in with the transmisson must be stripped down to the tune of a few thousand is a bit severe as the 1st step

I'd take a look at the colour of the transmission oil it should be a dark red colour if its black then its needs changing together with its oil filter. Also check its level with the gearbox warm and just after you've moved the selector through all the positions leaving it for a few seconds in each one and then back to park.

You can top up the box through the side fill plug if required and make sure you use the correct oil for your car as the fluids are not all the same. Some manufacturers recommended a change of the type of fluid - Speak to the local dealer and parts dept - they will advise you on the updated fluid to use..

If that’s all OK then check all the electrical connections of the gearbox, remove each connector in turn and spray with contact cleaner. Check that the wiring to the gearbox is in good condition with no chafing or frayed wire

if all of this is OK then the sump has to come off to clean out the filter screen

Customer: replied 2 years ago.
Hi Matt:
thanks for the response. I would like to add a detail I have ommited earlier: Mechanic 1 said: transmission fluid is Contaminated and varnished.
when I asked to flush and replace with new oil he said: this might be worse because the whole system is used to this varnished oil and if you put new oil with new viscosity and there is a crack somewhere then it could be the worse thing to do.
Any feedback on this?
Expert:  Matt replied 2 years ago.


I wouldn't flush the unit with any cleaning agent as would potentially remove varnish

I'd still try some fresh oil though as it has to be replaced regularly

I don't think there's a crack as you'd have far worse issues

Customer: replied 2 years ago.
May I ask other questions- Dealer says it's $250 to flush and refill transmission fluid.Do you recommend using Sears/ Jiffy L or Volvo dealers? thx
Expert:  Matt replied 2 years ago.


you do need quite a lot of fluid which is most of the cost as to do the job right do you have to drain, fill, run it then drain and fill again to tottally refresh all the fluid as about a 1/3rd gets stuck in the torque convertor

you'll get the best combination of service and price by using an independent Volvo specialist, there's no need for a dealer to perform this task

Expert:  Matt replied 2 years ago.


do you still need help?

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