@EndGlory:
Hey
Both can be freely used to make requests. Below is the list of common expressions used in requests, sorted by politeness level from least to the most polite. (in question intonation)
て(just て form, used by men and women)/てくれ(mostly used by men)
てくれる
てくれない
てもらえる
てもらえない
てくれますか
てくれませんか
てください
てもらえますか
てもらえませんか
てくださいますか
てくださいませんか?
ていただけますか
ていただけませんか?
When it comes to てもらう and てくれる in statements, both imply that the speaker benefited in some way from the action, the first one often implies that something has been done due to it being requested earlier, why the other one doesn’t have that implication.
(私は)車を修理工に修理してもらった。
Mechanic repaired car for me. | I had my car repaired by mechanic.
Often implied: (The mechanic repaired my car because I have requested it.)
(私は)母に車を買ってもらった。
Mom bought me a car.
Often implied: (Mom bought me the car because I have requested it.)
母が(私に)車を買ってくれた。
Mom bought me a car.
Implied: (“Mom bought me the car out of her goodwill, I didn’t request it before.” or “it doesn’t matter if I requested it or not, my mom bought me a car.”)
But it is not always the case and てもらう can be also used when someone did something out of goodwill without being requested, and てくれる can be used when something has been requested. Though it is not usually that way.
So:
修理工が車を修理してくれた。
is also good.
I hope it is understandable,
Cheers