"ne...que" with an infinitive?

Question

The following is a sentence on a blog post explaining different uses of the word "tout":

Je ne peux pas vendre que des parties de la voiture – il faut acheter le tout. (I can’t just sell parts of the car – you’ll have to buy the whole thing.)

Or, as I would translate it more literally: "I can't sell only parts of the car -- it's necessary to buy the whole thing."

I am wondering about that "que". Is it really a "ne..que" construction, with the "ne" being deleted (and the que moved after the infinitive, for some reason); that is, is it really the following:

Je ne peux pas ne que vendre des parties de la voiture.

(I'm guessing that "ne..que" precedes an infinitive if I want to apply "ne..que" to an infinitive; just as when "ne .. pas" is used with a conjugated verb, it surrounds it, but when used with an infinitive, it precedes it (as in "Je veux ne pas manger")).

If my guess is incorrect, then this is a new use for "que" that I have not yet learned. If so, it would seem that "que" is an adjective (or adverb?) meaning "only", and modifying "des parties de la voiture".

If this guess is correct, can I stick "que" before any noun or noun-phrase? Could I say, for example, "J'aime que les pommes rouges", or "Je vais donner des bon-bons à que les enfants qui sont sympas"?

Questions:
1. Is "Je ne peux pas vendre que ..." actually "Je ne peux pas ne que vendre..", but with the "ne" deleted [and the que moved after the infinitive, for some reason?]
2. If that is incorrect, is "que" just an adverb/adjective that stands on its own, that I can use preceding any noun or noun clause?

Answer 1

Je ne peux pas vendre que des parties de la voiture.

You are dealing with a "ne ... pas ... que ..." construction here. Without "pas", "I can only/just sell parts of the car, but not the whole thing". By adding "pas", you can negate this "only/just" restrictive sense: "It is not possible for me to sell just/only parts of the car".

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1) You cannot move "ne" and "pas" from their respective current positions.

2) The word "que {only/just}" in a restrictive sense always comes immediately before the word(s) that you want to qualify; the phrase "des parties de la voiture" is the very idea that you want to qualify with the restrictive "que":

not ... just/only parts of the car

(=) ne ... pas ... que des parties de la voiture

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Je ne peux pas que vendre des parties de la voiture.

If you place "que" right in front of the verb "vendre", on the other hand, you are now imparting a restrictive sense to the act of "selling":

I cannot just sell X, (but also have to do other things with it: offer an after-sales service etc.)

The idea enclosed in parentheses is implied.

Answer 2

1. Je ne peux pas vendre que... is just the negation of Je ne peux vendre que...
   Je ne peux pas ne que vendre is agrammatical.
   Here are some examples:

• Il n'a pas bu que de l'eau.
• Je repensais à tous les mirages que j'avais ainsi découverts dans notre appartement et qui n'étaient pas qu'optiques. (Proust)
• Sa boutique n'était pas qu'un lieu de rendez-vous. (Céline)

2. Here, que is still part of the ne ... que splitted negative so doesn't stand on its own but there are a few standalone que cases, e.g. :

• Aucun lieu pour se distraire que le cabaret. (No entertaining location but the cabaret)
• Une leçon qu'à moitié sue. (A partially assimilated lecture)
• Héloïse aime les pygmées albinos, mais pas que. (...but that's not the only people/thing she likes)

Examples and references from gabrielwyler.com:
- Ne...pas que... et ne...pas...que...
- Que absolu