The former Mthatha Bucks and Polokwane City manager resigned from his post as Venda Football Academy head coach last week to make way for the move.
He led the club for their first three games of the new Motsepe Foundation Championship season, picking up one point from three matches.
The Betway Premiership club posted on social media: "Marumo Gallants FC proudly welcomes Duncan Thaane Lechesa as our new assistant coach!
"Hailing from Bloemfontein, Coach Lechesa brings a wealth of experience."
Marumo Gallants have overhauled their technical team after a disappointing start to the 2026/27 Betway Premiership season, parting ways with head coach Phuti Mohafe and assistant Musa Bilankulu with immediate effect.
The KwaZulu-Natal derby between Richards Bay and AmaZulu headlines Friday night's Betway Premiership action, with the provincial rivals set to battle it out at the Princess Magogo Stadium.
The Betway Premiership returns on Tuesday as teams look to build momentum in the early stages of the 2026-27 campaign.
Phuti Mohafe has revealed that his desire for a fresh challenge, coupled with positive discussions between his representative and Marumo Gallants chairman Abram Sello, convinced him to leave Polokwane City.
