1999 V70xc Tranny fluid. drain fill or flush?

PapaHepcat · Post by **PapaHepcat** » 12 Sep 2015, 19:03

Took a look at my ATF fluid today and it's on the outs. My v70 has about 180k miles, I've only owned it for about 9 months, and I have no idea if it's ever been changed.

So I'm curious what folks' opinions are: Drain & Fill or Flush? Not a power flush. I'd be doing it myself by hooking up a hose to the cooling line or whatever.

I'm looking for simplest process. I usually can work on whatever, but I'm VERY burned out on working on stuff at the moment after dropping the tranny on my truck.

Post by **FLXC90** » 12 Sep 2015, 19:15

Do the fluid replacement by pumping out the trans cooler line and replenishing through the dipstick tube, 2.5 qts. per shot, is I think, the standard.

Post by **RussB** » 12 Sep 2015, 19:19

The fluid replacement by pumping out the trans cooler line and replenishing through the dipstick tube, 2.5 qts. per shot is the way to go. Probably overkill, but I did my 850's auto tranny every year for the 13 years I drove it. Never had any transmission issues in 270k miles

Scholz · Post by **Scholz** » 12 Sep 2015, 20:19

I replaced the fluid out the trans cooler line this morning. Was done in 30 minutes with 10 minutes of that being me trying to figure out how to use the snap ring clamps used my 98 s70t5. Used 3 gallons to get to the color i wanted.
Especially after doing it, I wouldn't think any variation of draining via the plug could be easier,quicker, or cleaner.

PapaHepcat · Post by **PapaHepcat** » 12 Sep 2015, 23:26

Oh geez. I just realized I put 1997 v70. I actually have a 1999. What in the world... I changed my initial subject line for any one who might come along later. Maybe it doesn't make much of a difference, but I've noticed that there were some changes mid '99 that have affected other things. So I thought I'd mention it.

I'll go with the cooler line method. And I won't even need to crawl underneath. Bonus.

So do I put the drain hose on the cooler line? Or in the cooler itself? I read somewhere that the direction the flow was reversed at some point. I don't know when that was. I searched for a step by step here, but came up empty. But looking at it and a quick search on YouTube, and it doesn't seem very difficult at all.

And I've read that some folks worry that changing all the fluid at once is bad because it shocks the system, or the car isn't used to suddenly clean fluid without junk, etc. Any experience with that?

Post by **alschnertz** » 13 Sep 2015, 09:18

I think you still need to crawl underneath initially to drain the pan.

Be sure to confirm that you have the proper type of fluid before you start too.

I think (been a while) I connected the drain hose to the supply-side cooler line coming from the transmission. At least that's how I would have approached it.

As for will the new fluid release some "junk" in the transmission? Yes, that's a possibility.
My opinion is that if a fluid change ruins the transmission, it probably was on its way out anyway. So I generally do the fluid change and take my chances. I've had decent luck so far with a '95 845T first change at 198,000 miles (now at 245,000) and a '01 S40 first change at 145,000 miles (now at 185,000).

Still, you need to evaluate if you want to risk it.

Post by **FLXC90** » 13 Sep 2015, 13:07

There is no more risk of debris/gunk released into your transmission this way. than there is draining and filling from drain plug. The "shock" to the system people referred to was the loss of suspended particles acting as a friction agent in the fluid. But more likely, the suspended grit is acting as a fluid abrasive, wearing parts and blocking fluid paths.

If you connect your dump line prior to the trans cooler, think about using a can of cooler cleaner before you are done. Don't reintroduce a pint of old crap into the fresh stuff. (<10 bucks a can) But you have to replace both O-rings too.

johngxc · Post by **johngxc** » 20 Sep 2015, 11:14

FLXC - I've done my trans fluid twice. On my 2000 XC fluid flows from the tranny out of the top hose to the cooler.

I don't understand your "cooler cleaner". What/how does this work? I just replaced the radiator, and only about 8 oz of transmission fluid flowed out of the bottom radiator fitting - not sure this is all that was in the radiator and return hose, but it might be a small quantity compared to the volume of fluid in the transmission.
I've heard the main issue in a full fluid replacement after a long period is that the transmission has adaptive settings, and over time the settings adjust to those appropriate for old fluid. With nasty old fluid, the new fluid has sufficiently different characteristics that it takes some time for the settings to readjust to the new fluid and shifts may not be optimal while it's readjusting (not sure if this means slippage, harsh shifts, or something else). I've heard of engine cleaning resulting in e.g. oil leaks, but I fully agree it's hard to see how old (abrasive, etc.) fluid is helpful to a transmission.

Post by **FLXC90** » 20 Sep 2015, 14:26

At your local parts store it will be with the additives and stuff, or ask. It is an aerosol can with a plastic hose that you inject into the system, it starts with a cleaner, then you invert the can and use propellant to purge the residue. Then just hook your hoses back up.

If you have access to VIDA/DICE, I guess you reset the fluid counter for the transmission adaptation.(?)

johngxc · Post by **johngxc** » 20 Sep 2015, 16:30

Interesting. If not worried about cleaning, one could presumably just blow out the cooler. I'll try this next time.