A transmissão precisa de limpeza.

Precisa de comes from the verb precisar, which in Portuguese often means to need.

In European Portuguese, precisar de + noun is very common:

• precisar de ajuda = to need help
• precisar de água = to need water
• precisar de limpeza = to need cleaning

So:

• A transmissão precisa de limpeza. = The transmission needs cleaning.

A very literal word-for-word breakdown would be:

• A transmissão = the transmission
• precisa de = needs
• limpeza = cleaning

Even though de is present in Portuguese, you would not normally keep it in natural English translation.

Because limpeza is a noun, meaning cleaning or cleanliness.

The structure here is:

• precisar de + noun

So the sentence is built like:

• needs cleaning
• not needs clean

If you want to use an adjective or a past participle idea like cleaned, Portuguese would normally use a different structure, for example:

• A transmissão precisa de ser limpa. = The transmission needs to be cleaned.

Both are natural, but they are slightly different in form:

• precisa de limpeza = needs cleaning
• precisa de ser limpa = needs to be cleaned

A is the feminine singular definite article, meaning the.

So:

• a transmissão = the transmission

The noun transmissão is feminine, so it takes:

• a in the singular
• as in the plural

Examples:

• a transmissão
• as transmissões

Yes, transmissão is feminine: a transmissão.

There is no perfect rule that lets you guess the gender of every noun just from the ending, although many nouns ending in -ão are masculine. That is why this word can surprise learners.

The safest way is to learn the noun together with its article:

• a transmissão

That helps you automatically remember the gender.

It depends on context.

Transmissão can mean several things, including:

• transmission in a vehicle or machine
• broadcast or transmission of TV/radio
• transfer or passing on of something, such as data or disease

In this sentence, because of precisa de limpeza, the most likely meaning is a mechanical transmission, such as in a car or other machine.

So in context, this is probably something like:

• The transmission needs cleaning.

Both are possible, but they are slightly different.

precisa de limpeza

This is more general. It means the transmission needs cleaning as a type of maintenance.

precisa de uma limpeza

This sounds a bit more concrete, like it needs a cleaning or a clean-up.

So:

• A transmissão precisa de limpeza. = The transmission needs cleaning.

• A transmissão precisa de uma limpeza. = The transmission needs a cleaning / could do with a clean.

The version without uma is very natural when speaking generally about maintenance or condition.

In standard European Portuguese, the more natural form is:

• A transmissão precisa de ser limpa.

That is because precisar normally takes de.

So these are good options:

• A transmissão precisa de limpeza.
• A transmissão precisa de ser limpa.
• A transmissão precisa de uma limpeza.

For a learner of Portuguese from Portugal, it is best to remember:

• precisar de + noun
• precisar de + infinitive

Examples:

• Preciso de ajuda. = I need help.
• Preciso de sair. = I need to leave.

It is fairly neutral and natural. It would fit well in:

• a mechanic’s report
• a maintenance note
• technical conversation
• everyday speech about repairs

It does not sound especially literary or especially slangy. It is just a normal, practical sentence.

Yes. Limpeza can refer either to:

• the act of cleaning
• the state of being clean

In this sentence, it clearly means cleaning as a maintenance action, not cleanliness in an abstract sense.

So here:

• precisa de limpeza means
• needs cleaning

Precisa is the 3rd person singular of precisar in the present tense.

The subject is:

• A transmissão = the transmission

So the verb must also be singular:

• A transmissão precisa...

Compare:

• A transmissão precisa de limpeza. = The transmission needs cleaning.
• As transmissões precisam de limpeza. = The transmissions need cleaning.

Depending on context, a native English speaker might say:

• The transmission needs cleaning.
• The transmission needs to be cleaned.
• The transmission could use a cleaning.
• The transmission needs a clean.

The most direct and natural match is usually:

• The transmission needs cleaning.