Twice now, rolling at 30-50 mph, I've floored the gas pedal, the ZF has downshifted, and then.... CLUNK or Ka-WHAM! goes into neutral OR SOMETHING instead of returning to
the gear from whence it came after the RPMs came up.

Thought I was gonna leave sprockets all over the highway both times.

Ideas?

 

And you haven’t had a Transmission Fault Message immediately afterwards?

Try a drain and fill with a reset. If that doesn’t solve it, I would look at the solenoids in the valve body.

 

Does it drive normally afterwards? I once broke a drum sprag (basically a ratchet) which made the transmission lose drive. After some manual gear changing it eventually returned to normal. Over the coming days it would randomly lose drive, usually when coasting, and finally it stopped working altogether. Disassembly determined the sprag had sheared. It was an easy fix.

 

I agree with GD to get the ATF changed (not flushed) and hopefully that fixes the issue, then you can take it from there.... could get expensive if it’s a gearbox internal problem.

Good luck

 

Are you sure it's the transmission? Sounds like it's in the Reduced Performance mode, which caps rpms at 3,000. It's like hitting a wall when you exceed 3,000 rpm.