Working with transmission fluid exposes me to many types of businesses necessary to the process of base oils and additives, becoming the high-performance automotive fluids needed for the advanced technology vehicles of today. One of the most interesting “players” these days is ZF Friedrichshafen AG, or the ZF Group. Originally called Zahnradfabrik Friedrichshafen (Gear Factory of Friedrichshafen). It was founded in 1915 by Count Ferdinand von Zeppelin to manufacture gears for Zeppelin airships and is still headquartered in Friedrichshafen, southern Germany. The company now specializes in engineering and manufacturing for the automotive industry and is one of the largest automotive suppliers in the world. ZF has 162 production facilities in 31 countries, with approximately 160,000 employees as of 2023.
My first experiences with ZF automatic passenger car and truck transmissions were during the 1960s with the introduction of the 3HP20 3-speed automatic transmission. ZF began supplying automatic transmissions to major German auto manufacturers (Mercedes-Benz, DKW, Porsche, and BMW) as well as French manufacturer Peugeot and Italian manufacturer Alfa-Romeo. The automatic transmission fluid required was the readily available GM DEXRON. In the 1970s, with worldwide subsidiaries and factories opening in India and South Korea, ZF introduced the 4HP18 series of 4-speed automatic transmissions and by the mid-1980s had a huge presence with European and Asian OEMs. The specified fluid was still the GM DEXRON II, which was the most readily available licensed fluid of that time. But things were quickly changing, and ZF was looking closely at the fluid as an important commodity they needed more control over.
The move to improved fuel efficiency led ZF to develop the first 5-speed automatic transmission with the new 5HP18 introduced in 1991. This was a pivotal moment for ZF, as from now on, ZF engineers would specify the type of ATF going into their transmissions. Transmissions with a black tag still used the GM DEXRON II ATF (red color). Transmissions with a green plate or label on the pan used the new ZF Lifeguard 5 fluid (yellow color). This was a game-changer for the transmission fluid aftermarket, which had been producing three red automatic transmission fluids that covered almost every application of the time. The new warranty (now extended) was tied to using the proper type of fluid, and for the first time, fluid color was used to deny warranty for using the “incorrect fluid” for service.
ZF was one of the first adopters of ATF that was not red, and it changed how ATF was sold and marketed. The complexities of emerging standards for ATF began to emerge when various OEMs, including GM, Chrysler, Daimler-Benz, BMW, Honda, Hyundai, Nissan, Toyota, and Volkswagen, started to develop standards, test methods, and certification programs for the ATFs considered vital to the protection of their transmission technology. Also mindful of the extended warranties that were now driven by new customer expectations. Most OEMS jumped on the “proprietary service fluid required for warranty” bandwagon. ZF was an early adopter of exclusive use of their specified fluid for warranty service and was also the first OE to declare their new ATF was reverse compatible for earlier production transmissions when they specified Lifeguard 5 for 4-speed ZF transmissions produced after the introduction of Lifeguard 5.
By the 1990s, ZF had expanded into China and, in 1999, introduced the first 6-speed automatic transmission, with series production starting with BMW in 2001. Currently, ZF produces around one million 6-speed automatic transmissions annually. To meet the engineering requirements of the new 6-speed, ZF introduced the Lifeguard 6 (amber colored) automatic transmission fluid. This was their first reduced viscosity ATF and (according to ZF) was “composed of high-quality semisynthetic base oil with additives which are customized to the individual components, also providing specialized protection and thus increasing the service life of all transmission components.” By 2006, ZF had produced its 10-millionth passenger car automatic transmission, and ZF had become the largest supplier of automatic transmissions to the automotive industry.
In 2007, ZF introduced its version of the 8-speed automatic transmission, designed to achieve an 11% improvement in fuel efficiency compared to the standard 6-speed automatic transmission. Production began in 2009 and became the go-to technology for automotive OEMs worldwide. They released a new fluid specific to the application, ZF Lifeguard Fluid 8 (also a reduced viscosity ATF and now the color is green), specifically developed for use in their 8-speed automatic transmissions and some 6-speed ZF automatic transmissions. The notion of “fill for life” was now part of ZF’s marketing strategy, and the disconnect between regular service and fluid changes was likely to create problems for the aftermarket and service technicians trying to deal with customers who now expected unlimited mileage with no requirement for service. It didn’t start out that way. At one time, the ZF Lifeguard 6 service interval was 100,000 kilometers or 62,000 miles. Better fluids (Lifeguard Fluid 8), extended warranties, and a desire to minimize the cost of maintenance prompted ZF to extend the oil change interval to 150,000 kilometers or 93,000 miles. In recent years, they have backed off the “fill for life” nonsense with a statement in their product data sheets saying, “In operating conditions with high temperatures and loads or with unknown vehicle use in the past, it can make sense to change the transmission oil at shorter intervals.”
2011 saw the ZF introduction of the world’s first 9-speed transmission, with Land Rover being the first OEM using the new “world-class” transverse-mounted application for the project. Never one to miss an opportunity for a new product, ZF developed Lifeguard Fluid 9 for use in 8-speed (reverse compatible) and 9-speed automatic transmission (also a reduced viscosity ATF, and now the color is blue). It is also noted that “only Lifeguard Fluid 9 may be used” for the 9-speed automatic transmissions.
By 2013, ZF had become the supplier of 8-speed and 9-speed automatic transmissions for Chrysler (which later became Daimler-Benz, then FCA, and is currently Stellantis), further expanding the number of OEMs that used ZF’s step automatic transmissions in their cars and trucks. Today, ZF automatic transmissions are used by most automotive OEMS worldwide.
Because the ZF transmissions have become so common, the millions of ZF automatic transmissions needing service fluids have created a lively aftermarket marketplace full of fluids that claim to be “suitable for use” when it comes to ZF transmissions. When you look closely at what is available, the cost of suitable products can vary wildly, with no explanation of why there is so much variability in the cost from one source to another. Pulling one example out to break down the problem offers insight into why transmission service technicians and mechanics have such a hard time with customer-driven service intervals and cost-effective fluid choices for servicing ZF transmissions. The ZF 8HP50/ Chrysler 850RE is a good example to use. In the ZF-provided document that lists approved fluids for this transmission, there are 15 ZF-approved fluids. The list includes the ZF Lifeguard Fluid 8 with part numbers for Porsche, Audi/ VW, BMW, Bentley, Aston Martin, Iveco, Jaguar, Land Rover, and Mopar (8&9-speed ATF). When you add the Lifeguard Fluid 9 (reverse compatible with the 8-speed), the list grows and includes Honda and Mercedes-Benz. As of late last year (hard to predict where prices are currently going) the lowest price for ZF approved fluid was Lifeguard Fluid 8 at around $20.00 per liter with other OE approved ATFs ranging from $21.00 for Honda ATF Type 3.1, Mopar 8- and 9-Speed ATF at $26.00, Lifeguard Fluid 9 at 25.00 (all ZF approved service fluids for the ZF 8HP50/Chrysler 850RE). In fact, when you price ZF-approved fluids for 8-speed applications, the price range is $21.00 to $88.00, depending on which OE source you decide to use. For the ZF 9-speed fluid applications, the price spread was smaller, starting at $21.00 low (Honda Type 3.1) with a high of $61.00 (BMW), depending on the OEM. For the service provider, this creates a situation where the customer is caught in the middle, not knowing what to do when confronted with outrageous prices for fluid they believe should cost much less. This is usually the point where many shops make a critical error and choose a less expensive fluid (not on the ZF-approved fluid list) for service to keep the service affordable. The mistake they make isn’t the quality of the fluid chosen; it’s the red color of the fluid. By not asking the right questions about the warranty status on the vehicle, they risk having to pay for a transmission if the unit fails or needs repairs and ends up at the OEM dealership. The OE dealership mechanic notes the wrong color transmission fluid, and the warranty is denied based on “improper fluid used for service”. This doesn’t mean the service provider did anything wrong or used an unsuitable product. It just means the OE has now “wiggled” out from under their warranty obligations. It can be pursued in a court of law, but the expense and capricious nature of judges and the legal system often result in the service provider having to pay for an expensive transmission at the end of the process.
The best way to handle this is to practice what I call “risk aversion”. When the customer decides to service their “fill for life” ZF transmission, the fluid choice decision should be driven by two factors. First, is the vehicle still under warranty, not just the OE warranty? If there is an extended warranty company supplying the warranty, the advice is the same (using an approved fluid is the best choice). If the vehicle is no longer under warranty, then the choice of service fluid falls to the customer. Second, this should be their documented decision, with a clear understanding that the ultimate decision on the type of ATF used for service rests with them, not the service provider trying to save them money on what can be an expensive service. When the customer is clearly informed of their options, the burden of “incorrect fluid used for service” becomes the problem of the vehicle owner, not the shop owner.
There is one other potential warranty problem that concerns ZF automatic transmission service that has popped up in the last few years that’s worth mentioning. When I was growing up, DIY was the standard in my neighborhood, and we all changed our own transmission fluids based on whatever interval we thought appropriate (30,000 miles comes to mind). Over time, there are fewer of us who perform our own service, but there are still dedicated DIY guys who service their transmission at the OE-recommended interval or their preferred service interval. There’s absolutely nothing wrong with that, but the issue of warranty on a vehicle can become problematic if your DIY efforts can’t be verified by a suspicious OE service manager in the event you have transmission problems that warrant a visit to the dealership. The truth is, service managers at dealerships believe that changing the fluid for the ZF automatic transmission by the owner will void the warranty. In reality it doesn’t, but the burden of proof that the proper fluid was used (meaning receipts for proper amounts of approved service fill for that specific transmission) along with records of mileage accumulation between service and type of service (pan drop or full flush) lies with the owner that performs his own service. They may question your ability or procedure, but if you have done your research and followed OE service procedures, you should be okay. There are plenty of ATFs available in the aftermarket suitable for servicing ZF transmissions, but you need to make sure you meet warranty fluid requirements if the warranty is in place. If not, you have many fluid options from expensive to not, but be aware, when the OE warranty expires, the last guy that did the service may be the one on the hook if the transmission fails after a recent service. The dealership tells the owner it was because the wrong color fluid was used for service, even if the warranty is long gone.
