I've heard plenty of stories about blown seals in ZF transmissions after being flushed with a machine. These transmissions have rubber o-rings inside, so they don't like too high of a pressure. I am not going to chance it.

What is the proper procedure for changing fluid and filter in ZF 4HP24? Drain, drop the pan, replace filter, refill? Is there a way to drain the torque converter? Or do you repeat drain-refill-drive cycle a few times until the fluid is clear?

I am thinking about either Amsoil (I had good luck using it in ZF boxes on my Land Rovers) or Redline. I am going with synthetic fluid, and it does not work well when mixed with conventional ATF.

Any gotchas I should watch out for?

 

I dont see how a machine could damage the orings... the machine is ran by the tranny and it exchanges fluid as it runs. unless the orings are already gone i dont see how it can kill thr tranny

 

Just repeat the cycle. I used Mobile 1.

 

As said above.

The filter is a stainless mesh thing, and I would do 6 or 7 drop and refills with your desired fluid, then if you REALLY want to, drop the pan and replace that mesh, I did NOT change the filter on mine, or the XJ40. Once I knew it was a mesh (as compared to a Dacron) that thought ceased.

Fluid is fluid, and the trans cares NOT what brand it is.

I run Synthetic in ALL my autos, and have doen so for a very long time. YES I have heard ALL the snake oil talk on seals popping, valve bodies blowing, yack, yack, yack. NEVER had an issue.

The only auto trans failure I have ever had was with an old DG in the S Type 3.4ltr, and that unit was sooooooo old anything was likely to happen with any spec trans oil I might have used. That DG makes an excellant boat anchor for my tinnie, and the Jag motors along with a BW66 doing what it does best.

 

I just ordered 2 bottles of Amsoil flush and the 13 quarts needed to flush and fill my ZF tranny. I am looking forward to doing this (once and for all) and will report back accordingly.

I did this on my manual transmission 6 speed Audi S4 and the difference was quite noticeable with regard to vibrations, shifting smoothness and gas mileage.