ZF8 Fluid - To flush or just change

[PKmode]

Let's talk maintenance for a second. My 2012 Prestige (APR DP) is getting old on me. Last Fall I did the TB, WP and carbon cleaning along with a basic tune up. Now I just cracked 100K the other day and really got to thinking about doing some PM to the trans. I realize at 100K, I should have probably done it sooner but also feel like that isn't completely out of line as ZF recommends servicing at 80K miles. Of course Audi's stance is 'lifetime' but we know better than that.

I'd like to do a full flush so I get ALL the fluid changed and pumped out of the Tq convertor and valve body but I know that can be somewhat risky, usually with higher miles though. So, taking into consideration the miles (100K), do I do a full flush and risk possible contamination from old oil contaminants clogging up the channels in the valve body; or just change the fluid and filter all call it a day? I have VCDS and can do the DIY change but would rather have a shop do the full flush if it's deemed 'safe'.

Who has done either or and what was your experience? Thoughts and input appreciated.

[DrSilverShot]

Drain & fill baby!


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[Audibot]

On my B7, the first time I changed the fluid was at 108k miles. At that time, I just refilled with the fluid (incl cleaning pan, replace filter, etc). Felt better.

Second time, took it to the shop and they used Lifeguard 8 (previously Lifeguard 6). Trans starting slipping on the way home, so brought it back. Shop owner recommended Redline D4, and to do several drain and fills to remove the old fluid. They did exactly that (said the old fluid was very watery; not as viscous and oil-like as it should have been). Trans felt so much better, and shifts were crisp again.

My recommendation is to just do the simple drain and fill. But if you want to get as much out as you can would be to do several drain and fills in succession--should get you closest without ripping the thing out

[p3u]

I recently did this.

I first did a drain and fill and 1k mileage later performed a drain and replaced the filter. I did it this way as the drain and fill only removes approximately 50% of the fluid and a flush seems too risky.

After a short period of new time with the new fluid it helps clean the internals and at that point did the second round.

[Valpo A7]

I want to change my 2012 but at this point I am almost afraid to. The original owner followed the fill for life Audi mentality. I bought it at 142K and now have 171K on the ORIGINAL FLUID. The tranny shifts fine and is very smooth but I am afraid of changing at this point and wind up flushing shit out of the nooks and crannies.

[A6sport]

I wouldn't touch it. Been driving Audi Cars with ZF slush boxes for 30+ years. The recommended service interval was 30k miles on the 3 speeds in my C3 cars. I was faithful and got my ass burned 3 times. Between 2-5k later I'd have a failure. AoA did replace one unit for me gratis.

My C5 has 300K it's my winter beater now and I've never cracked a pan screw. That "lifetime" fluid is doing just fine... I tried to have Audi change it at 30k, and 60k and they wouldn't do it. I stopped asking...

If you really want to do it for peace of mind, when I lived in Chicago, I had ZF rebuild one of mine, they use to have a service center in Vernon Hills (Northern burbs) Not too far from you in Milwaukee. There is another place in WI that used to do great work on ZF units called BlauParts Service, you probably know it? It might not hurt to give them a call and pull their coat tails about a best course of action.

[PKmode]

p3u, Sounds like a good way to go.

A6Sport, you had flushes done, yes? If at the dealer, then yes. That's what I was saying was risky as far as clogging an internal channel in the valve body. I don't think draining and replacing fluid and filter would net the same results. Also, I know the Blau guys. They aren't too far from one of my customers up towards Sheboygan.

Thanks, guys.

[A6sport]

Not on the 8 speed nor the C5 5 speed tip. These days I just roll the dice.

[Audibot]

Find a good indy shop and you can cut out some of those ungodly stealership prices

[dorothy_c7]

I've seen another zf8 trans fluid replacement. It was like an all day affair for the guy. Hey would do exactly what everyone has be saying. Drain some drive fill some drive drain some drive. A little bit at a time. I was like sheeesh this is a process that could result in error. I'm having my indy shop I trust dearly, do this for me.
[SideNote]: I work for a little local residential and commercial fertilizing company. Any time we flush products with other liquids. We do the same thing, always keeping fluid running throughout the pumps to prevent damaging any components. It makes since to be easy and not do a complete flush

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[dorothy_c7]

I recently did this.

I first did a drain and fill and 1k mileage later performed a drain and replaced the filter. I did it this way as the drain and fill only removes approximately 50% of the fluid and a flush seems too risky.

After a short period of new time with the new fluid it helps clean the internals and at that point did the second round.

Idk if u or anyone else have the official Audi c7 workshop guide. (Literally has everything for $30). I believe I found it under [Servicing 8-speed Automatic Transmission] section 7.2 Filling and Draining ATF page 78. Also I'll ask my 2 friends that work at the same Audi as techs. One is actually the floor supervisor.

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[p3u]

I've seen another zf8 trans fluid replacement. It was like an all day affair for the guy. Hey would do exactly what everyone has be saying. Drain some drive fill some drive drain some drive. A little bit at a time. I was like sheeesh this is a process that could result in error. I'm having my indy shop I trust dearly, do this for me.
[SideNote]: I work for a little local residential and commercial fertilizing company. Any time we flush products with other liquids. We do the same thing, always keeping fluid running throughout the pumps to prevent damaging any components. It makes since to be easy and not do a complete flush

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You can't drain more than half the fluid at any given time. That's why that person did it as described and why I did it on two separate occasions.

[p3u]

Idk if u or anyone else have the official Audi c7 workshop guide. (Literally has everything for $30). I believe I found it under [Servicing 8-speed Automatic Transmission] section 7.2 Filling and Draining ATF page 78. Also I'll ask my 2 friends that work at the same Audi as techs. One is actually the floor supervisor.

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You can't do the job for $30. If you are DIYing fluid alone for the correct type would be $80 minimum (4 liters) for ZF Lifeguard 8 and OEM filter kit $60.

[dorothy_c7]

You can't do the job for $30. If you are DIYing fluid alone for the correct type would be $80 minimum (4 liters) for ZF Lifeguard 8 and OEM filter kit $60.

That's for the guide book. But u right u right lol

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[dorothy_c7]

You can't do the job for $30. If you are DIYing fluid alone for the correct type would be $80 minimum (4 liters) for ZF Lifeguard 8 and OEM filter kit $60.

That's for the guide book. But u right u right lol

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Not buying it but why would they sell them in 9x 1liter increments? Europarts ftw tho. I love locally be able to pick up goods. https://www.europaparts.com/automati...k-8-speed.html

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[p3u]

Not buying it but why would they sell them in 9x 1liter increments? Europarts ftw tho. I love locally be able to pick up goods. https://www.europaparts.com/automati...k-8-speed.html

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You only get ~4 liters out on a drain and fill, about 5 if replacing filter. Torque converter holds about half of the fluid...

[AudiSportback]

Coming from bmw with years of experience with zf transmission. Always Drain & Fill. Never flush. The one time I flushed the transmission it died 3 weeks later. Please do not hit the lifetime fluid crack pipe.

[PKmode]

Not buying it but why would they sell them in 9x 1liter increments? Europarts ftw tho. I love locally be able to pick up goods. https://www.europaparts.com/automati...k-8-speed.html

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FCP sells a similar kit. I'll compare. https://www.fcpeuro.com/products/aud...iABEgKnj_D_BwE *Edit, it looks like the FCP kit includes the filter while Europarts does not.

As p3u stated, the 9L of fluid accounts for the whole system including what's in the torque convertor and valve body. If you just drain, you're not getting 1/2 the oil changed. That's why the dealer does a "flush" which uses a pump and pulls new fluid in as the old is pushed/flushed out. As mentioned above, THIS is when larger contaminants could potentially come loose and will flow through the system, potentially causing a clog in the valve body.

Additionally, to Doroth_C7, It's true the fluid needs to come up to full operating temp before being topped off. If you drain twice in the same day with a drive in between, I can see it taking a while. It shouldn't be all day though. Especially if you have access to a lift.

[jrsAudiA6]

You might want to check this thread for more info on this subject. https://www.audizine.com/forum/showt...d+transmission

[PKmode]

Thanks. Read it quick. I think I'm planning the DIY fluid drain and refill and add new filter, etc. I'm not doing the diffs as I'm not tracking the car. I'll report back down the line when I have time to tackle this.