Seja no motor, seja no câmbio, verificamos tudo.

Yes — seja is the present subjunctive of ser.

In this sentence, seja ... seja ... is a set expression used to present alternatives, with a meaning like:

• whether ... or ...
• be it ... be it ...
• whether it’s in ... or in ...

So Seja no motor, seja no câmbio means something like whether in the engine or in the transmission.

This is a more formal or polished structure than a simple no motor ou no câmbio.

Because the pattern is exactly seja X, seja Y.

It creates a balanced structure:

• Seja no motor, seja no câmbio...

This repetition emphasizes that both possibilities are covered. In English, it is similar to saying:

• whether in the engine or in the transmission
• be it in the engine, be it in the transmission

If you said only one seja, it would not sound right in this construction.

It is understandable and natural, but it sounds a bit formal, written, or advertising-like.

You may see it in:

• ads
• technical descriptions
• professional language
• formal writing

In everyday speech, Brazilians might more often say something simpler, such as:

• No motor ou no câmbio, verificamos tudo.
• Se for no motor ou no câmbio, verificamos tudo.

So the original sentence sounds polished and professional, which fits a service or business context.

No is the contraction of:

• em + o = no

So:

• no motor = in the engine
• no câmbio = in the transmission

This contraction is extremely common in Portuguese.

Other examples:

• na oficina = em + a
• nos carros = em + os
• nas peças = em + as

Portuguese usually uses an article in places where English often does not.

So Portuguese tends to say:

• no motor
• no câmbio
• na oficina
• no carro

rather than leaving the noun bare.

A literal English speaker might expect something like in engine or in transmission, but Portuguese normally wants the article here: in the engine, in the transmission.

Here, câmbio means the vehicle’s transmission or gearbox.

That is important because câmbio can mean different things depending on context, such as:

• gear shift / transmission in automotive language
• exchange or exchange rate in financial contexts

In this sentence, because it is paired with motor, the automotive meaning is clearly intended.

Grammatically, verificamos can be either:

• present: we check / we inspect
• preterite: we checked / we inspected

The form is the same in both tenses for nós.

In this sentence, the most natural reading is present tense:

• we check everything
• we inspect everything

That is because the sentence sounds like a general statement about a service a company provides.

Because Portuguese often drops subject pronouns when the verb already makes the subject clear.

So:

• verificamos tudo already tells you the subject is we

Adding nós is possible, but it usually adds emphasis or contrast:

• Nós verificamos tudo. = We check everything.

Without emphasis, leaving out nós is very normal and natural.

The commas separate the paired expression seja ..., seja ... from the main clause.

Structure:

• Seja no motor, seja no câmbio, = introductory alternative/concessive frame
• verificamos tudo = main statement

The commas help the reader hear the rhythm and understand that the sentence means:

• whether in the engine or in the transmission, we check everything

They are not optional here in normal writing.

Yes. That is a very close literal rendering.

A few possible English equivalents are:

• Whether it’s in the engine or in the transmission, we check everything.
• Be it in the engine, be it in the transmission, we check everything.
• Engine or transmission, we check everything.

The second one is closest in structure, but it sounds somewhat formal in English too — just like the Portuguese original sounds somewhat formal.

Not usually in the narrow English sense of verify.

In Portuguese, verificar often means:

• to check
• to inspect
• to examine

So in this context, verificamos tudo is more naturally understood as:

• we check everything
• we inspect everything

A direct word-for-word translation using verify may sound too stiff or slightly misleading in English.

Yes, but the tone changes.

For example:

• No motor ou no câmbio, verificamos tudo.

This is simpler and more direct. It still makes sense, but it loses the more formal, polished feel of seja ... seja ....

Compare the tone:

• Seja no motor, seja no câmbio... → more formal, rhetorical, professional
• No motor ou no câmbio... → more straightforward, everyday

So both work, but they do not sound exactly the same.

Yes. The structure suggests it doesn’t matter which of the two it is — the statement still holds true.

So the nuance is something like:

• whether it’s one or the other
• in either case
• regardless of which area we’re talking about

That gives the sentence a stronger, more comprehensive feel than simply naming two parts of the car. It sounds reassuring, like a service promise.