Hi Sticky,
I'm not a native spanish speaker, nor fluent by any stretch of the imagination, but this link will probably help you a lot.
http://spanish.allinfo-about.com/vocabulary/expressions/ex-proverbs.htmlIt seems that there is no direct translation for
"The squeaky wheel gets the oil/grease".
This site equated the saying to:
"Niño que no llora no mama" which roughly translates as:
"The child who does not cry, does not nurse".
Interesting that the English version is positive and the Spanish equivalent is negative in context.
There are plenty more verbs on this site, with their equivalents and direct translations for you to compare.
Although with proverbs you just have to learn them as wrote, I find them a fascinating insight into the differences between and influences on our two cultures.
For example, one that struck me immediately was:
"Clothes do not make the man" versus
"El hábito no hace al monje" (The habit does not make the monk).
Almost identical phrase in form and meaning, but like so many other Spanish sayings when compared to their English equivalents, completely revealing the religious influence at the very heart of this culture compared to that in England.
Hope this is helpful to you, and accurate

. If not, I am sure a native won't hesitate in correcting me!