986 Forum - The Community for Porsche Boxster & Cayman Owners - View Single Post - 986 Tiptronic gearbox

Smallblock454 · 07-01-2016, 08:17 PM

Hello JFP in PA,

never have seen in it person how it was done on a 986/996. As far as i understand from the readings in the german Porsche forum they use the oil cooler lines to do it on the 986/996.

Also you do not need a pressure system if you AT oil pump generates enough pressure to forward the oil. And i'm not convinced that a pressurized system is better in any ways, because you use an overall higher pressure that is normal in the system. As you know how the EHS works and that you are not allowed to clean it with pressurized air for example, i'm not shure if it is a good a idea to use high pressure at all at this AT.

As you know there are several manufacturers that at that time used the "life time" fillings on their AT transmissions without a torque converter drain plug.

Mercedes-Benz themselve uses the Tim Eckart system and a very similar exchange system like Tim Eckart in their german workshops for their cars of that period with no torque converter drain plug. Might not be that efficient, but works. And better to change the ATF this way than change the complete AT under warranty, because many cabs over here in Germany are Mercedes brand and the Mercedes AT 772.6 just failed in that cab cars within short time when the ATF oil wasn't changed. So they reduced from life time filling to a 60 TKm complete ATF change interval including ATF oil filter.

And yes, you need around 12-13 litres of ATF to change a 8.5 litres MB 722.6 AT system with that method. But you can exchange the whole ATF in that way, while else you can only dilute when you cannot flush the toque converter.

So the real problem with this MB lifetime filling AT is you don't have a drain plug on the torque converter. I think this is the same with the 986 ZF AT, which is also very very similar constructed to the MB 722.6 AT.

But i think we have discussed that already. So i don't want to be annoying. Maybe there are just different kinds of views how to solve the problem. Think you agree that the idea of a lifetime ATF filling doesn't work as initially intended by the car and transmission manufacturers in practice.

Regards, Markus

07-01-2016, 08:17 PM	#16
Smallblock454 Registered User Join Date: Jun 2014 Location: LB, Germany Posts: 1,513	Hello JFP in PA, never have seen in it person how it was done on a 986/996. As far as i understand from the readings in the german Porsche forum they use the oil cooler lines to do it on the 986/996. Also you do not need a pressure system if you AT oil pump generates enough pressure to forward the oil. And i'm not convinced that a pressurized system is better in any ways, because you use an overall higher pressure that is normal in the system. As you know how the EHS works and that you are not allowed to clean it with pressurized air for example, i'm not shure if it is a good a idea to use high pressure at all at this AT. As you know there are several manufacturers that at that time used the "life time" fillings on their AT transmissions without a torque converter drain plug. Mercedes-Benz themselve uses the Tim Eckart system and a very similar exchange system like Tim Eckart in their german workshops for their cars of that period with no torque converter drain plug. Might not be that efficient, but works. And better to change the ATF this way than change the complete AT under warranty, because many cabs over here in Germany are Mercedes brand and the Mercedes AT 772.6 just failed in that cab cars within short time when the ATF oil wasn't changed. So they reduced from life time filling to a 60 TKm complete ATF change interval including ATF oil filter. And yes, you need around 12-13 litres of ATF to change a 8.5 litres MB 722.6 AT system with that method. But you can exchange the whole ATF in that way, while else you can only dilute when you cannot flush the toque converter. So the real problem with this MB lifetime filling AT is you don't have a drain plug on the torque converter. I think this is the same with the 986 ZF AT, which is also very very similar constructed to the MB 722.6 AT. But i think we have discussed that already. So i don't want to be annoying. Maybe there are just different kinds of views how to solve the problem. Think you agree that the idea of a lifetime ATF filling doesn't work as initially intended by the car and transmission manufacturers in practice. Regards, Markus