I need your help please. The rear main seal on my 73 Buick is leaking. A mechanic I took the Buick to for servicing said that the crank, rods, pistons, etc need to pulled to do the replacement of a rear main seal. A friend of mine at work said it sounds like you have to pull the engine and tranny which is a pretty big job. What is the ground truth on what needs to be done to change the rear main seal? Thus far I have spent $670 in service costs & I still have an oil leak. A new radiator, new (rubber) valve cover gaskets and a new water pump have been put on the 73 Buick. The mechanic also completely cleaned out the oil pan & thoroughly cleaned the oil pump pickup screeen that was full of sludge, tarry black clumps of jello like oil deposits. The Buick used to belong to my nearly 81 year old Dad. My Dad rarely drove it & just let it sit. It had 54,428 miles on it when my Dad transferred title to me. In a 20 year period (Nov93-Jul13) my Dad only drove it for 8,200 miles; an annual average of 410 miles.