8 speed transmission oil change

[eric1728]

Hi all, i have been reading up on changing transmission oil. The reason being that i am unsure what oil is filled from factory and is it at the correct level. The idea is to use Penrite ATF BMV which is a highly regarded Australian automotive oil manufacturer, they make good stuff. Penrite ATF BMV is recommended for the ZF 8 Speed. Having done this on previous car transmissions i have always noticed better transmission operation. I think many manufactures are more concerned about the cost of the oil rather than the quality. So the question is with all previous transmissions i have owned what i simply do is drain the transmission via the drain plug, add the same amount of oil at around the same temperature as the oil that was drained. Take the car for a drive and repeat 3 to 4 times. This ensures the transmission/torque converter has new oil throughout. Then on the final fill go through the correct level checking process. I would do the Pan/Filter at much higher mileage. This would simply be an oil change. Does anyone who knows these transmissions see an issue with doing it this way. Thanks for any info.

 

[Different Drummer]

I had contemplated doing this after installing an aftermarket pan with a repeatedly reusable drain plug. I am not sure how many times I would want to reinstall the OEM plug if at all. Not to mention that when I did do my transmission service the OEM replacement pan I purchased does not even have a drain plug. I still might go that route next time around.
There is another consideration though. With the truck not running you most likely will not be able to replace the volume that you removed. I suppose in theory after draining the Trans. and VERY carefully measuring what you removed. ( don't spill any ). You MIGHT be able to jack the side of the truck up on the fill side of the transmission thus raising the fill port and making the fluid flow away from the fill port to get the same volume of fluid back into the trans mission that you removed. Or, just jack the rear up and do the fill procedure as described by ZF. Lots of posts here regarding that. However, I am guessing that you are trying to get away from going through that procedure and doing a couple of short mileage drain and fills to dilute out old fluid left in the Trans. Good luck which ever way you go.