S40 Transmission Fluid Change?

jdanielbaker · Post by **jdanielbaker** » 17 Apr 2012, 11:00

I have a 2001 s40 nearing 130k miles. As far as I know the transmission fluid has never been changed. Occasionally, when driven in heavy traffic for 45 minutes or so, i'll experience some hard shifts. Is this something that a transmission fluid drain and fill would fix? Or could it be some other problem that is allowing the transmission to get too hot? I've heard mixed stories on whether you should change fluid in a car with high mileage. Any advice is much apprectiated.

Post by **JDS60R** » 17 Apr 2012, 12:07

I would change it. Many prefer the drain and refill method (4 qts at a time). I like the full flush method unless the old trans fluid is black and nasty. Being in ATL I think you should take a look first as it gets hot in hotlanta.

jdanielbaker · Post by **jdanielbaker** » 17 Apr 2012, 12:30

Thanks for the advice. i would not say the fluid is black, but it definitely brown. So is there no truth to the story that the transmission utilizes dirt/debris as a friction enhancer as it gets older? i read something to that effect on a ipd transmission flush kit.

Post by **JDS60R** » 17 Apr 2012, 22:30

There is truth in that the floating slag and clutch pack material would increase friction in many areas. I just wouldn't want it in mine.

Post by **MoVolvos** » 18 Apr 2012, 01:44

You may choose to do a drain and fill first to see if it improves it. Friend's 2002 Odyssey had hard kick downs so the drain and fill eliminated the problem till he was in very heavy commute traffic. Did the flush and he has not had a problem since.

https://www.matthewsvolvosite.com/forums ... =1&t=47877

Blessings,
BKM
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jdanielbaker · Post by **jdanielbaker** » 02 Jun 2012, 19:23

so i changed a little over half of the fluid and it seems to shift a little smoother. is there any reason to gradually change the fluid as some suggest? or is it better to get all new fluid in?

Post by **MoVolvos** » 03 Jun 2012, 01:07

jdanielbaker wrote:so i changed a little over half of the fluid and it seems to shift a little smoother. is there any reason to gradually change the fluid as some suggest? or is it better to get all new fluid in?

The reason it is not a good idea to do a gradual change is:

Hypothetically, if you had 8 oz of metal shaving in your fluid compared to 1 oz. If you just replace half the fluid you still have 4 oz compared to 0.5 oz. If your fluid has problems draining and filling 3 times at 50% each time will still leave you with 1 oz of metal shavings. If you flush, the metal shaving in the residual film would be considerably much, much lower.

Changing someone's bath water with 50% clean water for reuse or draining 50% of wash cycle laundry water with rinse water are unheard of practices. Even so used, dirty or contaminated Trans Fluid mix with new as a way to replace just does not make sense. I think it makes sense for the Auto Manufacturer as they want to repair or replace your car sometime.

Blessings,
BKM
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rjr1031 · Post by **rjr1031** » 22 Jul 2019, 08:57

How to change transmission fluid in 2001 volvo s40?