Originally Posted by wpoll

Don't hear too many ZF users with the selector shaft seal leaking - more common on the GM transmissions.

The ZF has two well-known weak spots as it ages - the mechatronic (connector) seal and the internal "bridge" seal.



The mechatronic seal simply allows trans fluid to weep out. The bridge seal shrinks with heat/age and leaks fluid internally, causing a loss a of fluid pressure in the valve body (mechatronic). This can lead to a range of issues.

If you open this transmission up, it's worth replacing them all. And given the cost of the fluid (esp. OEM fluid!!), you'll likely want to maximise the result from the spend....