Emergency services were called to junction 26 of the M6 at Orrell following the incident at around 3.20pm on Monday.
They found a truck carrying chippings had turned over as it was leaving the southbound carriageway on the exit road.
The vehicle came to rest across the outside lane of the slip road and part of the verge, with the inside lane being covered with chippings.
The outside lane was shut but motorists were initially able to get past the incident without difficulty.
However, Highways England said the entire slip road had to be closed for a short time for the chippings to be swept up.
It is not clear if there were any injuries.