A version of this story first appeared in the Oct. 2 issue of The Hollywood Reporter magazine. To receive the magazine, click here to subscribe.

No franchise is more important to Universal Pictures than Fast & Furious, the car-racing series whose seventh installment grossed $1.5 billion worldwide this year. But the effort to mount an eighth picture is proving more difficult than first imagined for the studio.

As its announced April 2017 release date inches closer and screenwriter Chris Morgan works on the script, Universal still has not found a director for the next outing. And in this case, it seems that the job will involve more than just the usual challenge of overseeing a big-budget thrill ride. There also is the recent exit of studio co-president of production Jeffrey Kirschenbaum, who oversaw the series, and the prickly matter of star-producer Vin Diesel.

Following the death of Paul Walker in November 2013, Universal enlisted Diesel, 48, as the face of the series, updating fans on Furious 7 via his social media and putting him forward to speak about the cast and crew’s desire to finish the movie, which was about halfway completed when Walker died in a car accident. Diesel not only was a veteran of the series going back to the 2001 original (though he took a break, returning for the fourth installment), but he had the credibility of having been close to Walker, personally.