You should always take care when forwarding from one action to another. The most common "bug" that arises from doing this is that of disappearing or overwritten form values (note the quotes). This is not actually a bug but normal behavior. You just need to understand what the framework is doing.
In the case of wanting to pass parameters when forwarding from one Action to another, my experience has been that this is usually a code smell. Code smells should result in refactoring to eliminate the code smell.
But first, why do you need to pass parameters to the second Action? Are the parameter values already in the ActionForm that Action 1 received with the current request? If that is the case, you don't need to do anything since the parameters are already in the request. Just make sure that the ActionForm associated with Action 2 has corresponding fields that will receive those parameters.
If the parameter values were not submitted with the request, I would say refactor and extract the code in Action 2 that uses the parameters. Put that code into a Helper class instead. Then you can use the Helper class from both Action 1 and Action 2 without having to go through the error-prone exercise of forwarding from one Action to another.