Do I need to change the automatic transmission fluid?

Al-volvo · Post by **Al-volvo** » 29 Jan 2011, 18:39

Hi Folks.
1998 S70, with 78,000 miles; runs fine
I'm about to change the timing belt (I know, I know, should be changed at 70k); but aside from doing this, "if it ain't broke, don't fix it" is my adage.
I'm seeing what else needs to be changed so I can get it done at the same time.
Regarding the automatic transmission fluid:
The volvo owners' manual simply suggests "inspecting" the automatic transmission fluid and states nothing about changing it every so often.
On this forum I see people chiming in about how often to change the automatic transmission fluid but elsewhere I've read that if that fluid's never been changed (as in my car's case) to leave it alone...

So, must I change the automatic transmission fluid? Thanks. Al

Post by **Ozark Lee** » 29 Jan 2011, 19:23

Must you change it - no. Should you change it - yes.

Most of our folks start to run into problems at around 110 to 120 k miles and you can prevent many of those problems with a fluid change now at your mileage.

The timing belt is a bigger deal though. When it breaks it is pretty much game over for the engine.

I like your "if it ain't broke, don't fix it" logic but that results in epic engine damage when it comes to the timing belt breaking. With your mileage you have an easy belt change, it is just the belt which only costs around $25.00.

...Lee

peacock · Post by **peacock** » 29 Jan 2011, 19:27

its a matter of as you said it "if it aint broke dont fix it"
there are indeed rare cases were excessive transmission wear can leave you stuck after changing the fluid because none of the material formerly giving it friction remains in the unit.

As far as i could tell my car had never had it done and i was seeing some minor harsh gear changes in between gears 2 and 3. this was 190,000 miles into the cars life span. the fluid was VERY dark brown/black.

If you have any doubt that it would actually hurt the car then i wouldn't do it, however with how rare that is (based on how often Ive seen it come up) then you would probably be safe. it takes about $50 worth of fluid to do it right, and about $4 in hose + 1 5gallon bucket.

Post by **boosted5cyl** » 29 Jan 2011, 19:40

Timing belt has to be done, its like russian roulette otherwise. They dont really "wear" they slip or snap resulting in at best 4 figure damage to the engine.

Transmission fluid, You could send a sample off for analysis to blackstone, cost about $25. Its not just the miles, the aging and seasoning has an effect on the presence of acids, friction modifiers and whatnot over time. Personally, I'd do a series of drain and fills with Dexron VI rather than a flush. Theres no filter worth talking about in the AW transmissions, you dont want to wait until you have a problem and if the fluid is already in bad condition then the damage is already done.

If it aint broke dont fix it adage is not a good way to go with older cars in my experience. The way I look at it is if it aint broke, it will. The question is how critical is it and when is it likely to fail.

Post by **vjaneczko** » 29 Jan 2011, 21:51

peacock wrote: As far as i could tell my car had never had it done and i was seeing some minor harsh gear changes in between gears 2 and 3. this was 190,000 miles into the cars life span. the fluid was VERY dark brown/black.

So I'm curious; did you leave it alone or change the fluid? I'm in the same boat and it's been in the back of my mind for some time.

Post by **jblackburn** » 29 Jan 2011, 22:17

If you have never changed it, change out a small bit at a time - drain and fills of the transmission pan, about 3 1/2 quarts at a time, and space out the changes a few weeks to a month apart. After 4 of those, you should have mostly new fluid in there and the transmission will be happy with it being introduced to new fluid slowly.

Otherwise shifting will continue to get worse and your transmission will die. In addition to being dirty, the fluid breaks down and loses its lubricating properties over the years.

Post by **anjill182** » 30 Jan 2011, 04:43

Changed the fluid in my 98 v70xc @ 150k and my son's 00 s40 @ 140k and it made a big difference in both.

cdnbluez · Post by **cdnbluez** » 30 Jan 2011, 20:09

Bought a 1998 V70 in December with 180k on it. Following week I took it to my mechanic to change the timing belt and flush the tranny. He said he would drain/refill 3-4 litres, and told me to come back in a month to do it again. Will be taking it in this week.

Excimer · Post by **Excimer** » 09 Feb 2011, 09:58

2010 XC90 with 27.5 K on odo. Bought New. Oil changes every 5K. I am about to embark on a 3500 drive. No towing ever. Should I change the tranny fluid? Vehicle is 13 months old and get 75% city and 25% highway with 25 K per year. Thoughts??

Post by **vjaneczko** » 09 Feb 2011, 11:04

Excimer wrote:2010 XC90 with 27.5 K on odo. Bought New. Oil changes every 5K. I am about to embark on a 3500 drive. No towing ever. Should I change the tranny fluid? Vehicle is 13 months old and get 75% city and 25% highway with 25 K per year. Thoughts??

I'd check the owners manual, as I'm not sure on the interval for your ride. Two thoughts enter my head; (1) you're probably getting close the the suggested change interval, but (2) they may suggest an initial change due to a break-in period.