I've decided to change the transmission fluid in my 2005 S-Type with V6 engine and ZF6HP26 transmission. I had done some research that said ZF Lifeguard 6 is the right fluid.
But genuine ZF fluid is quite expensive so I looked for an alternative and Valvoline Maxlife looked like a much cheaper suitable substitute. On the Valvoline site the Product Information (PI) sheet says that Maxlife is suitable where ZF Lifeguard 8 is the original oil. I asked Valvoline if ZF 8 was OK to use where ZF 6 is called for. Valvoline claims that ZF 8 supersedes ZF 6, so yes they wrote. I found out that's not quite true after I had the following exchanges with ZF transmissions (ZF Services North America, LLC.):
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MY QUESTION: My Jaguar has a ZF6HP26 transmission which calls for ZF LifeGuard 6 fluid. Can I use ZF LifeGuard 8 instead of ZF LifeGuard 6?
ZF ANSWER: For your Jaguar, we recommend ZF Lifeguard 6 or the OEM equivalent..
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MY QUESTION: Does that mean I can't use ZF LifeGuard 8 instead of ZF LifeGuard 6?
ZF ANSWER: ZF Lifeguard Fluid 8 is the same fluid as Lifeguard Fluid 6, but it has additives that LG6 doesn't. ZF doesn't recommend the use of LG8 in the 6hp26 unless you own an Audi, which requires the additives in LG8. There was a special software update for the Audi when changing from LG6 to LG8. That software isn't available for the Jaguars. If you do not use LG6 you could experience transmission issues..
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MY QUESTION: I asked something about flushing vs. drain and fill.
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ZF ANSWER: We do not recommend flushing the transmission. A drain and fill with a filter/pan replacement is sufficient. You will need 5-7L of fluid..
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MY QUESTION: Do you consider flushing a bad thing?
ZF ANSWER: A flush is very expensive considering the cost of fluid. The best flusher is a Hot Flush. The problem is most shops use a generic fluid to flush your transmission, because if they used the correct ZF fluids it would be very expensive. It is preferred not to contaminate the transmission with the wrong fluids. Therefore, a drain and fill works best..
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I also found Pentosin ATF 6 (NOT Pentosin ATF 1) is the correct fluid and it's a little cheaper than ZF Lifeguard 6. But after careful consideration, I've decided to bite the bullet and use ZF Lifeguard 6 for a drain and fill with a filter/pan replacement. For the slightly higher cost I've decided not to mix the ZF and Pentosin fluid types.
I ordered 7 liters though I may only need 6, but I can return the 7th liter to Walmart if it only uses 6. I found a genuine ZF drain/filter kit for a reasonable price on ebay. Hope this saves someone a lot of research.
But genuine ZF fluid is quite expensive so I looked for an alternative and Valvoline Maxlife looked like a much cheaper suitable substitute. On the Valvoline site the Product Information (PI) sheet says that Maxlife is suitable where ZF Lifeguard 8 is the original oil. I asked Valvoline if ZF 8 was OK to use where ZF 6 is called for. Valvoline claims that ZF 8 supersedes ZF 6, so yes they wrote. I found out that's not quite true after I had the following exchanges with ZF transmissions (ZF Services North America, LLC.):
*************
MY QUESTION: My Jaguar has a ZF6HP26 transmission which calls for ZF LifeGuard 6 fluid. Can I use ZF LifeGuard 8 instead of ZF LifeGuard 6?
ZF ANSWER: For your Jaguar, we recommend ZF Lifeguard 6 or the OEM equivalent..
*************
*************
MY QUESTION: Does that mean I can't use ZF LifeGuard 8 instead of ZF LifeGuard 6?
ZF ANSWER: ZF Lifeguard Fluid 8 is the same fluid as Lifeguard Fluid 6, but it has additives that LG6 doesn't. ZF doesn't recommend the use of LG8 in the 6hp26 unless you own an Audi, which requires the additives in LG8. There was a special software update for the Audi when changing from LG6 to LG8. That software isn't available for the Jaguars. If you do not use LG6 you could experience transmission issues..
*************
MY QUESTION: I asked something about flushing vs. drain and fill.
*************
ZF ANSWER: We do not recommend flushing the transmission. A drain and fill with a filter/pan replacement is sufficient. You will need 5-7L of fluid..
*************
*************
MY QUESTION: Do you consider flushing a bad thing?
ZF ANSWER: A flush is very expensive considering the cost of fluid. The best flusher is a Hot Flush. The problem is most shops use a generic fluid to flush your transmission, because if they used the correct ZF fluids it would be very expensive. It is preferred not to contaminate the transmission with the wrong fluids. Therefore, a drain and fill works best..
*************
I also found Pentosin ATF 6 (NOT Pentosin ATF 1) is the correct fluid and it's a little cheaper than ZF Lifeguard 6. But after careful consideration, I've decided to bite the bullet and use ZF Lifeguard 6 for a drain and fill with a filter/pan replacement. For the slightly higher cost I've decided not to mix the ZF and Pentosin fluid types.
I ordered 7 liters though I may only need 6, but I can return the 7th liter to Walmart if it only uses 6. I found a genuine ZF drain/filter kit for a reasonable price on ebay. Hope this saves someone a lot of research.