The sale of the rental property triggers the release of passive losses carryover so you can deduct any carryover rental losses against income? how to do that turbotax?

Yes, you are correct. When you sell a rental property you are allowed to use all passive loss carryovers in the year of sale.

Passive Activity Loss Entry:

Assuming your passive losses were carried over each year, this will be a separate and identifiable entry which will carry to the Schedule E.  The full remainder of passive loss carryover is used in the year of sale as an expense. This is combined with your overall rental gain or loss to your Form 1040. 

• When you are on the screen 'Do any of these situations apply to this property?' (Property Profile section), be sure to check the box under Carryovers. 
• See my notes below on entering the sales price/expenses for each asset inside the rental activity.

You need to dispose of the property by telling TurboTax how and when it was disposed of.  Follow the instructions below.

1. Click on Search (upper right) > type rentals > Enter > click Jump to .... link (or click the first FAQ and click Go to rentals)
2. Answer the questions and on under Rent and Royalty Summary, click Edit
3. Click Update to the right of Assets/Depreciation.
4. Click Edit to the right of each asset to be disposed of
5. Go through several screens until you get to Tell Us More About This Rental Asset
6. Click on This item was sold…….   And continue to answer the questions

You might also review information here.

Example of arriving at the selling price and sales expenses for each asset in your rental activity.

Example:  Original Cost (of each asset on your depreciation schedule)

$10,000 Land                = 13.33% 

$50,000 House              = 66.67%

$15,000 Improvements  = 20%

$75,000 Total                 = 100%

Multiply each percentage times the sales price/sales expenses to arrive at each individual sales price/sales expense.