Mitochondrial intermembrane chaperone that participates in the import and insertion of some multi-pass transmembrane proteins into the mitochondrial inner membrane. Also required for the transfer of beta-barrel precursors from the TOM complex to the sorting and assembly machinery (SAM complex) of the outer membrane. Acts as a chaperone-like protein that protects the hydrophobic precursors from aggregation and guide them through the mitochondrial intermembrane space. The TIMM8-TIMM13 complex mediates the import of proteins such as TIMM23, SLC25A12/ARALAR1 and SLC25A13/ARALAR2, while the predominant TIMM9-TIMM10 70 kDa complex mediates the import of much more proteins. Probably necessary for normal neurologic development. Heterohexamer; composed of 3 copies of TIMM8A and 3 copies of TIMM13, named soluble 70 kDa complex. Associates with the TIM22 complex, whose core is composed of TIMM22. Highly expressed in fetal and adult brain, followed by fetal lung, liver and kidney. Also expressed in heart, placenta, lung, liver, kidney, pancreas, skeletal muscle and heart. The twin CX3C motif contains 4 conserved Cys residues that form 2 disulfide bonds in the mitochondrial intermembrane space. However, during the transit of TIMM8A from cytoplasm into mitochondrion, the Cys residues probably coordinate zinc, thereby preventing folding and allowing its transfer across mitochondrial outer membrane (By similarity). The disease is caused by variants affecting the gene represented in this entry. Belongs to the small Tim family.