Timmins left Tranmere in July to join Stockport and link up with manager Paul Simpson, whose spell at Edgeley Park proved short-lived.
He will take up work with Rovers` goalkeepers Tony Warner and Joe Collister as well as helping with the youth and school of excellence keepers at Prenton Park.
Australian Miotto has left Prenton Park after seven months in the job to concentrate on his business interests.
Source: PA
Source: PA