Need Some Advice

[X53Jay4.8is]

Originally Posted by upallnight

Here's a link to problems associated with the ZF6HP26 trans as installed in a BMW. The fact that your trans is slipping leads me to suspect the torque converter could be one of the problem. The ZF6HP26 trans was the first trans that could lockup the torque converter in all forward gears.

Common Problems Associated With The ZF 6HP26 Automatic Transmission

As quote from the website on BMW lifetime ATF.

"Service interval recommendations are too long (BMW). On BMW vehicles equipped with this transmission, the factory rates the fluid to last a lifetime. The unfortunate fact is that this is simply not accurate. Tests have shown that the fluid starts breaking down at around 62,000 miles. It is therefore recommended that the fluid be changed every 50,000 miles. Doing so will assure you a long transmission life span."

Yeah the torque converters do fail on the 6hp but some diagnostic analysis needs to be performed to determine where the customer should go. If the Tranny never got any fluid and filter service then I would suspect that the tranny is on its way out component seals have begun to break down. If I had purchased at 70K I would have replaced the trans fluid along with the mechatronic for piece of mind service.