The ZF 8 Speed & Lifetime Fluid Fill

Just did a 100K oil change on the '11 Audi A4 Avant and got to thinking about doing the other fluids despite the lack of any factory recommended service intervals (Lifetime Fill). This car has the 1st Gen ZF 8 speed (8HP I think) autobox with a metal pan and integral ZF center diff. There's a cast aluminum trans mount that covers the center diff & rear portion of the trans pan. That'll have to come off for access to perform any service to the trans or center diff. The trans/center & front diff layout is the same as pictured below:

ZF recommends a procedure for a fluid change that involves shifting in & out of certain gears for specific times & verifying the fluid temp @ 40C before topping off: https://aftermarket.zf.com/go/en/aftermarket-portal/passenger-cars-and-lcv/know-how/useful-tips/transmission-oil-change/

I haven't checked yet, but doubt my generic OBD reader will give me a trans temp reading. Also a little concerned about getting the fill procedure & fluid level exactly correct. This is not something I want to have any nagging questions on after completion.

Given these concerns, I called the dealer to get a quote on a diff & trans service. The SA recommended against doing the trans service, mentioning that flushing could create more problems & is not worth the risk (He quoted F/R diff fluid change only & never mentioned the center diff).  I didn't ask for a trans flush service but thanked him for checking anyway.

I want to keep this car for another 100K and a trans fluid life of 200K/20 years seems optimistic to me. 

Has anybody on board done this service on an Audi Quattro with ZF8? If so, did you need a scanner to get accurate fluid temp, or just use an IR gun on the pan? I have a BMW that will need the same service pretty soon & note that it has a plastic pan, so temp reading would be more of a challenge. Any hints on experience with the ZF8 and Audi center diff fluid changes would be appreciated.

Go use a qualified independent shop. There is the same type of "trans must be a X temp, removed fluid level must be measured, etc" on the DCT's in BMWs. 

If you can find the local German indy place in town, it's likely filled with ex-dealer techs.

I don't have any Audi-centric ZF8 experience but my 2015 Ram has the 8HP70. Here is the FCA service procedures for filling the fluid. On this version, the pan must be replaced for a filter change because the filter is integral to the pan. I would use a scanner to determine the fluid temp.

Does the computer display not have a trans temp? Our Jeep with this transmission has it.

The old recommendation for not changing automatic transmission fluid on high mileage vehicles had to do with varnish formation.  I'm not familiar with what lubricant/fluid is used in the 8HP.  On traditional automatics, as the transmission fluid detergent additives wore out and the fluid changed from red to brown, varnish would form on the internal surfaces.  Fresh fluid would dissolve the varnish and sometimes it would come off in chunks, with the particles getting lodged in valve bodies, solenoids and such.  

How awesome is it that the ZF fluid will illuminate under a blacklight?

If you can measure what comes out of it id just put that amount back in. 

I have a 6hp ZF trans in my 09 4.6 Genesis sedan and it sounds like a similar procedure. I ended up using a temp gun on the pan and for the past 10k miles it seems to be close enough to the right level to not cause issues. a tricky part with doing that (atleast on the 6hp) is the pan is finned so you have to get the temp gun measuring in between the fins to get a better temp reading.

Ravenol makes trans fluid specific for ZF automatics and they are the cheapest I found that I knew 100% was acceptable for the ZF.

The 6hp is also a 'lifetime sealed' unit which means it's good enough to make it through the end of the factory warranty, everywhere i've read suggests 100k intervals. I picked my Genesis up with 190K miles on the clock so i figured it would be worth it to change the fluid, luckily it looked like someone at some point had changed it before as the plastic drain plug was stripped. So hopefully it's got some more life left in it with having 2 fluid changes in it's life.

I'll probably perform the fluid swap on my Ram in the coming months. It only has 33k miles on it but I hate the placement of the drain plug so I'm going to be replacing the pan with a nice finned aluminum pan that has a 2 extra quart capacity.

The engine has to be running and the fluid temp has to be under 86°F so you have to be quick. It doesn't sound hard but its tedious because the lift has to be level, the engine has to be running (hot exhaust) and the fluid heats up quick.

edizzle89 said:

I have a 6hp ZF trans in my 09 4.6 Genesis sedan and it sounds like a similar procedure. I ended up using a temp gun on the pan and for the past 10k miles it seems to be close enough to the right level to not cause issues. a tricky part with doing that (atleast on the 6hp) is the pan is finned so you have to get the temp gun measuring in between the fins to get a better temp reading.

 

Ravenol makes trans fluid specific for ZF automatics and they are the cheapest I found that I knew 100% was acceptable for the ZF.

 

The 6hp is also a 'lifetime sealed' unit which means it's good enough to make it through the end of the factory warranty, everywhere i've read suggests 100k intervals. I picked my Genesis up with 190K miles on the clock so i figured it would be worth it to change the fluid, luckily it looked like someone at some point had changed it before as the plastic drain plug was stripped. So hopefully it's got some more life left in it with having 2 fluid changes in it's life.

Thanks for this. Neither of my ZF8 cars have a trans temp readout on the MMI, so I'll grab the code reader I have & see if it displays there. 

A colleague at work was an auto & diesel tech for years. His advice lined up with the dealer SA - "You're thinking the old way, synthetic fluids are much better now - If it's not acting up or leaking fluid, let it be".

I appreciate everybody's thoughts on this & think I'll drop by the local Euro car mechanic for another opinion as well.