Pastor Maldonado looks set to start the Monaco Grand Prix from the back of the grid, with his Williams team planning to change his gearbox before the race.
The Venezuelan, who won from pole position in Spain a fortnight ago, had been scheduled to start 19th on the grid due in part to a 10-place grid penalty he was given for causing a collision with Sergio Perez in final free practice.
But following examination of his car by Williams after qualifying, it was found that there was a problem with his gearbox - perhaps as the result of a crash in final practice - that means he will face a further five place drop.
Chief operations engineer Mark Gillan said: "The car had a lot of damage in it, to the point where we are having to change the gearbox in it as well.
"There was a significant amount of damage to the car, so the guys did a really good job to even get it out for qualifying."
Gillan admitted that the qualifying result for Monaco was a disappointment, on the back of its success in Barcelona.
"I've no doubt we could have done P4 or P5, with a decent clean run, or maybe even higher. But Pastor did not match his Q2 time and his time in Q3 was set with old super soft tyres, so there was definitely quite a bit more to be had.
"It's disappointing. But it is still good that we are disappointed because the pace is definitely there."