My son was driving his 02 300M 142000 mi on the hiway car was running fine.He then heard a noise the RPMs went up & the trans appeared to be slipping.He nursed it about a mi to a rest area & I had it towed home.Now if you put it in drive it will move forward but makes grinding noises wont do anything in reverse.The trans fluid is full&the fluid is not burnt at all Any ideas as to what it may be?
Thanks
Sal

Sounds like it may be in limp mode. You can usually get a trans shop to read the codes off of the TCM on those cars at no cost, that should tell you if you have an electrinics issue of a mechanical issue. If it comes to it and you want to swap that trans out you can usually find guys who will rebuild them for around $600.

No reverse tells me it's not in limp mode. It sounds like the tranny failed, especially if it's making ugly noises.

I just had this happen to my 04 intrepid and it wasted a planetary setup, the trans has to be gone through completely.