Drivers are advised to avoid junction 14 (southbound) on the M5 this afternoon.
One lane is blocked on the slip road while mechanics wait for part to arrive so they can fix a vehicle carrying an abnormal load.
The enormous lorry, which was transporting an electrical transformer for the national grid, broke down just before 2pm this afternoon, on the B4059.
The B4059 is closed in both directions, as the breakdown has happened between Tortworth Road and the M5 J14.
The 200 tonne truck, owned by Allelys Heavy Haulage Ltd., is too big to move off the road so repairs have to be carried out on site.
However mechanics have had to order a replacement part for the truck which is taking some time to arrive.
A lane of the slip road has been closed while mechanics wait for a replacement part to arrive so repairs can begin.
Junction 14 of the M5 near Leyhill in South Gloustershire has been affected. Traffic has been reduced to one lane on the entry and exit slip roads while mechanics wait for the part to arrive.
The 57-metre-long lorry was transporting a new transformer to the Iron Acton substation in South Gloucestershire.