1999 S70 GLT - Transmission Fluid Change ?

[Grantkat]

Ok Guys to change or not to change...This past weekend I replaced my Radiator and Heater Core. When I did, I obviously lost some transmission fluid when i pulled the 2 lines. After seeing I began to ponder - should I or shouldn't I change it.
My 1999 S70 is currently at 192K miles and some change, i bought it at 150K. I have zero past maintenance information other than mine. It has never had a hint of shifting or transmission issues. I have rebuilt transmissions on other vehicles, so I am pretty up to speed on them.
I have always gone under the rule of after a certain number of miles/length of time, you don't change fluid unless you are experiencing issues or the fluid of burnt.
this does not smell burnt. here are a couple pictures of the fluid. I have no idea what kind/brand of fluid that is had in it. Based on what I have seen in changing the various components, its probably not OEM level fluid but who knows..
It shifts smoothly and i have no issues right now.

Thoughts?

[volvolugnut]

That ATF looks too dark to me. With no records of when it was changed or what the fluid specs are, I would do a series of drain and refills.
volvolugnut

[erikv11]

My routine on new-to-me, 200k P80 Volvos with auto trans is
1 - completely change the fluid when I get the car. Light brown, dark brown, pinkish, no matter. I have always done all 13 quarts at once by pulling the ATF line from the cooler but of course a series of drain and fills in succession is fine too. One reason to change it all at once is to know you're not mixing fluids but it is a minor concern.
2 - thereafter drain and fill (3.5 quarts) every 30k or so
3 - use cheap, generic Dex III-compatible ATF. It works great and, well, it's cheap. My favorite is Supertech ATF at Walmart.

These transmissions are super hardy.

[jreed]

I agree with the above advice to change the fluid.

[Grantkat]

ok next question.
according to my VIN I have a AW42AWD gearbox (#8 in the VIN position)
I am thinking drain refill cycles, as opposed to pulling a line. Since i just installed the lines with new clips etc, im inclined to leave them alone. I am also superstious in that introducing new fluid in batches as opposed to a complete refill seems like a more consrvative approach (I am sure this has no reasonability to it). any thoughts as welcome.

1) for drain and refill, how many cycles is considered appropriate?
2) how long between drain refill cycles?

[abscate]

I do the Gibbons method on all my AT cars. Pull the top line and pump out 3 liters. Put three liters fresh back in.

If you put new orings on the lines they won’t mind being moved.

Drive 50-100 miles between cycles and then check fluid at end using factory approved method

The lore about not changing ATF comes ftom those who brought. Thrashed out trans to a shop , which the new fluid flushed out the crap and ended up non-running

[erikv11]

ok next question.
according to my VIN I have a AW42AWD gearbox (#8 in the VIN position)
I am thinking drain refill cycles, as opposed to pulling a line. Since i just installed the lines with new clips etc, im inclined to leave them alone. I am also superstious in that introducing new fluid in batches as opposed to a complete refill seems like a more consrvative approach (I am sure this has no reasonability to it). any thoughts as welcome.

1) for drain and refill, how many cycles is considered appropriate?
2) how long between drain refill cycles?

A conservative drain-refill approach is reasonable, even though it's not what I typically do. It's definitely safe! It's also easy to do.

1) If you drain the pan it should be 3.5 quarts. Published capacity of the AW42 system is 8.1 quarts. So after one drain and fill you are at 43% new fluid. Next change gets you to 68% etc. :

1 0.43
2 0.68
3 0.82
4 0.90
5 0.94
6 0.97
7 0.98

Many people choose 4 changes but pick your spot.

2) Up to you! I would guess the new fluid composition gets completely mixed within a few miles and then waiting has little additional effect, though there may be some slow dislodging of crud going on. At a minimum I'd try to use every gear including reverse. So, drive a couple miles or hours, a couple hundred miles, change it every Saturday for a month - I'd expect any of those to give equal outcomes.

[Grantkat]

thanks to everyone for contributing!!!

[Sveedy]

I seem to remember that one of the reasons (maybe the main reason) for the drain and refill approach, as opposed to the all at once option, was to avoid shocking the transmission by going from old to new fluid pretty much instantly. So with that in mind, I run about 100-200 miles between each change. I do 3 changes.

[volvolugnut]

I think there is another advantage of driving 100 miles or more. The fresh fluid will have more effective detergents and will do some internal cleaning between the drain cycles. The next drain will get the crud back out of the transmission.
volvolugnut