Transmittal rhymes with:
smittle, committal, noncommittal, smittle, acquittal, belittle, bittel, bittle, brittle, committal, hittle, it'll, kittel, kittell, kittle, knittel, knittle, littell, little, lyttle, noncommittal, pittle, pytel, rittle, skittle, smittle, spittle, tittel, tittle, vittle, whittle, zittel