401ks are all different...they have plan documents that specify their rules. I agree with the other poster that told you to call them.
The receiving broker dealer cannot initiate a rollover of a 401K. 401Ks each have their own paperwork that can be completely different from company to company. It isn't the same as transferring from one broker dealer to another. And insurance investment transfers are even more different. To add another element, some 401ks have a third party administrator that handles things. For example, we handle 401k investments, but each have one large account for the company. Our third party admin has the paperwork and distribution amounts.
The 401K must supply you paperwork (or at least the phone or online capability of directing where your money goes). A specific time frame isn't a given, because some plans won't let ex employees roll over until a certain time period has passed. On the forms, there will be a place to take a distribution (and it should state the tax ramifications, there is also probably a place to sign saying you have received the separate tax notification which they should provide to you), a place to transfer to another plan, or a place to directly rollover to an IRA. Submitting an ACAT (accounts transfer form) or any other document from your receiving firm won't help with a 401k.
Now, if they keep dragging their feet, and YOU KNOW that the plan time period is up and you are eligible to roll over, you could send them a letter stating that it is their fiduciary duty to represent the plan as intended, and that they are violating their own plan rules by not forwarding the documents you are requested.
I deal with rolling over client 401ks daily (I work for a financial firm) and they each have their own rules and "games", sometimes.