rear differential gasket

[Wesley 1]

not sure of position of shark fin on inside of gasket goeson 2014 sierra 1500 4x4.does anyone know??

 

[98trck]

just wondering, why have you opened the diff on a 2014 ?

 

[Wesley 1]

thats the same question the GMC mechanic asked.Super lube told me that it had breakin oil and was very black.I read all over on forums that people were changing oil a lot sooner to get shavings out and put a better oil like mobil1 and other quality oil in. Just for the record the oil was fine and didnt need changing.But to late....