From an evangelical perspective the teaching of "progressive revelation" applies here: the teaching on heaven and hell became more and more clear as further scripture was revealed, but Heaven and Hell are at least hinted at from the beginning. The idea of permanent separation from God is implied in Genesis 2:17, "in the day you eat of it you shall surely die".
Although it may be true that the Heaven and Hell are not so clearly delineated in the Old Testament as in the New Testament it is not true they are not there.
Whither shall I go from thy spirit? Or whither shall I flee from thy presence? If I ascend up into heaven, thou art there; if I make my bed in hell, behold, thou art there. (Psalm 139:7,8)
One feature in the Old Testament is that Hell is down and Heaven is up:
At the end of his sojourn on earth Elijah was taken up into Heaven:
And it came to pass, when the LORD would take up Elijah into heaven by a whirlwind... (2 Kings 2:1)
But Korah and those caught up in Korah's rebellion went down alive into the pit:
They, and all that appertained to them, went down alive into the pit, and the earth closed upon them: and they perished from among the congregation. (Numbers 16:33)
Our Lord's interpretation of Exodus 3:6 tells us that Moses's father, Abraham, Isaac and Jacob, though they were physically dead, yet they were spiritually very much alive:
I am the God of thy father, the God of Abraham, the God Isaac and the God of Jacob. (Exodus 3:6).
On this quote our Lord said "God is not the God of the dead, but of the living." (Matthew 22:32) The meaning is that when God revealed himself to Moses he would have Moses to know that he is an all-powerful, mighty God; and therefore God would not draw attention to Abraham, Isaac, and Jacob unless these people were being kept in spirit alive by his mighty power. I.e. God would not speak of four dead people as demonstrations of his power, except those people are alive in spirit.
So, even though this passage does not speak specifically of Heaven it does speak of an afterlife which the four that are mentioned are currently enjoying.
Even though Heaven and Hell are not named in Daniel yet they are described:
And many of them that sleep in the dust of the earth shall awake, some to everlasting life, and some to everlasting contempt. (Daniel 12:2)
This verse is similar to those ending the book of Isaiah describing both Heaven and Hell:
For as the new heavens and the new earth, which I will make shall remain before me, saith the LORD, so shall your seed and your name remain. And it shall come to pass, that from one new moon to another, and from one sabbath to another, shall all flesh come to worship before me, saith the LORD.
And they shall go forth, and look upon the carcasses of the men that have transgressed against me: for their worm shall not die, neither shall their fire be quenched; and they shall be an abhorring unto all flesh. (Isaiah 66:22-24).
This verse, of course, is quoted several times by our Lord as a description of Hell.
Obviously, this is by no means an exhaustive search... it merely demonstrates that it is not true that Heaven and Hell are not found in the OT.