Sorry I don't know how to answer your first question. Is my Christianity not based upon what my religion has taught me?
Even your original example... 'once saved always saved'... I think the belief or disbelief of that statement varies from religion to religion. It's not "Christianity" that changes, but rather our interpretation of the bible, guided by what religion we listen to. At least, that is what makes sense to me.
I may not understand how you're using the term "religion" then.
Within Christianity ... one Christian can believe they are "once saved always saved" and base that belief by referencing Bible scriptures. Another Christian can believe they are capable of losing their salvation depending on choices, etc. Both are part of Christianity ... the same religion. It's one example. Your next section makes me think you are using the word "religion" in a way different than I'm used to.
As to your second question.. I don't know what IOW means.
Sorry, internet shorthand

IOW means "In Other Words".
But yes, I absolutely believe that there are different truths in the bible, and each one is defined by what our religion teaches us. I have heard some religions believe that the way to get to heaven is merely to accept Jesus as your savior. Others believe it takes a lot more than that. Some believe you must speak in tongues. The bible does discuss each of these things, but I'm not sure there's any clear cut scripture with a numbered list. Wouldn't that be helpful? Here we have the 10 commandments, and here we have the 10 things you must do to enter heaven LOL
From this, I take it you view different denominations as different religions. Thus Pentecostals will be one religion, perhaps Methodists are another religion, etc. Yes ?
And I don't know what LOL means.
(Just Kidding)
I think I understand what you're looking for... if I believe something different from another Christian, do I accept that maybe I'm wrong and they are right?
Yes and no.
I accept that our interpretations differ. In a belief system, it's very ... hmm what's the word.. ignorant, I might say, to claim that I know the absolute truth and another's belief is wrong. In the same way that it would be ignorant to reverse the roles.
But I think that as long as we're both reading the same book God will grant us understanding in his own way.
This is more or less what I was looking for.
Having said that ... when you say this:
My belief is fundamentally based on one truth- the truth spoke in the bible. And in that truth, God is infallible.
How can you say your belief is based on one truth-the truth spoke in the bible, but in the next breath say those truths are defined by what the different religions teach, acknowledge they can differ, or not totally understand, etc ? Do you see that as basing your belief on something ill-defined, shifting, and allowed to be self-contradictory ? In this context, do you see religion and the bible as being the product of human beings only ?
For example, if I say, "I believe in the Constitution of the US" ... although a group of us may differ in how we think it should be applied, we have a common reference point. We may have different goals, different interpretations of what some things mean, etc ... but we are all referencing the same thing. What we CAN do, however, is amend it, change it .... change our minds, etc. IOW (in other words), it's probably not going to be viewed as infallible.
Do you see the bible and religion as something similar ? It's all subject to change and shift, and that's okay ?