The road starts at traffic lights just north of Guide Bridge station and heads west along Audenshaw Road. This is the only part of the A6140 which is single-carriageway as until the road was built it was the eastern end of the B6390. The road widens and bends round to the right as that road turns off to the left at traffic lights. We head north and go over the Ashton Canal before reaching part of M60J23, where two adjacent sets of traffic lights serve the west-facing sliproads. We then go past a retail park before crossing the A635 at traffic lights; that road serves the remainder of M60 J23, providing the other movements.
We soon reach another set of traffic lights from where a spur of the A6140 turns left back to the A635. Ahead is another retail park and we TOTSO right onto Lord Sheldon Way. We run alongside the Ashton branch of the Metrolink past Ashton Moss station. There's then a set of traffic lights for retail park access; at this point the Metrolink moves into the central reservation.
The road bends gradually round to the right and soon goes over the M60 to another roundabout. Road and Metrolink alike turn left (there's more retail ahead) and we the central reservation widens slightly to accommodate Ashton West station. There's a set of traffic lights serving a road that was here before the A6140 and we then pass between Sainsbury's and housing before reaching a roundabout by Ikea. Here we turn right and the Metrolink moves to the south side of the road. The northbound A627 comes in from the right at the next set of lights and so the block ahead to the following set of lights, where we meet the remainder of the A627, could be part of the A6140 or the A627. Either way the road now ends.