I was driving through the mountains of North Carolina yesterday with my family and not driving hard at all I came over the top of the hill started going downhill so I took my foot off the gas and was coasting down when I heard a noise and felt a jerk.

The Best way I can describe what happened was it felt and sounded like when you are accelerating and take your foot off the gas right when it’s about to shift and it jerks and makes a loud noise.

As soon as it happened the check engine light and the AT Check light came on. I was in sport mode as soon as I saw the lights come on I took it out of sport mode in the AT check light disappeared but the check engine light remain on.

I continued my journey to our family event about an additional 10 miles through the mountains. Only thing that was different was that I didn’t have full power when accelerating. I let the car sit for a few hours while you’re at the event and then we proceeded to head home.

The car felt completely fine and accelerated normal. I felt like I had full power all the way home about 45 miles through the mountains. The check engine light remains on.

Any ideas?


Details:
I have yet to read the code but is soon as I do I will post it.

2008 G35 sport

207,000 miles

At 168,000 miles I had the transmission rebuilt completely and the radiator was replaced.

That's a bit odd and a bit of a bummer since the tranny has already been replaced once. Definitely get the codes out of your car's computer and post those here for more help. See if you can get the transmission code as well. I don't know how to do that, but maybe the instructions are in the FSM. The FSM is broken into chapters and starts with the FWD chapter and table of contents. Here's a link if you haven't found it already:
http://www.nicoclub.com/FSM/G35/Sedan/2008/

Depending on what the codes say it might be time to drain the transmission and see if there are any shavings coming out. I've had the 5AT not engage before (on my 2k2 Maxima a couple times) but never had a similar issue where the system was in any form of limp home mode.

Good luck and keep us posted.