The decision is expected to be known before the start of the next round of the championship, next month’s Tour of Corsica.
One source told Autosport.com: “Jerome will be looking at tolerances, he might well look at other gearboxes as well.
“This decision to investigate further infers there wasn’t enough time to really get to the bottom it at post-event or it could mean there was a very strong defence from the team and that defence required further investigation.
“In terms of penalties if the car is found in contravention of the regulations, it could be anything from a time penalty to exclusion.”
An exclusion would meant that Ogier would not only lose his second place on the rally but also the championship lead.
A disqualification would drop him behind Toyota’s Jari-Matti Latvala and M-Sport team-mate Ott Tanak.
No-one from M-Sport was available to comment.