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Q: Fluid leak between engine and transmission possible slave cylinder

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I have a 2010 Ford Mustang GT 5 speed manual transmission V8 4.6 Litre, I had the valve covers and timing chain cover gaskets replaced to remove front of car oil leak but now there's a puddle of fluid under the car which seems to be between the engine and transmission , I have 2 diagnoses from 2 different shops , one says it's the rear main seal the other transmission shop says it's the slave cylinder for the clutch, the car will not shift into 1-2 or reverse gears while cold but after few minutes of city driving it will shift normal , until it warms up I have to Use 3rd gear assume the slave cylinder / clutch needs replacement but is the slave cylinder failure causing the fluid leak I see between the engine and transmission? I have brand new synthetic manual transmission fluid and brand new synthetic engine oil I cannot differentiate between the two fluids leaking , I know failed slave cylinder leak fluid that's confused with rear main oil seal leak sometimes , what is leaking ?

My car has 28798 miles.

First check the fluid level in the clutch master cylinder to see if it is getting low. If it is low on fluid then you have a slave cylinder leaking. If the fluid does not go low then you do not have a slave cylinder leaking. To find out if it is the engine rear main or the front transmission seal leaking then I would suggest adding oil leaking detection dye to the engine oil and not the transmission. The dye will show up under a black light. This way you can see if the engine rear main is leaking if the dye in the oil shows up in a few days.

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