Welcome, I'm Chris (aka Moose). Experts aren't employees / agents of Just Answer. We are independent service providers using the Site to sell their Expert knowledge to Customers. I strive to provide EXCELLENT 5 STAR service, let me know what's needed from me so your pleased.
It is rare to never a solenoid issue can cause loss of all forward gears in the 5R55 transmission. This is normally to blame on the linkage out of adjustment, or a forward clutch failure. Below is a link to all the things which can cause no Forward.
To diagnose this prior to doing any repairs you need to check the codes and have a line pressure test done, then a air test on the clutches. See the link below.
Thanks for asking your question and letting me try to help you.
If your confused on why or how to rate me, let me know.
I'm only paid from the deposit you've made when you rate 3,4, or 5 stars.
Follow up/Reply as many times as needed before or after rating.