Yes. You would need to seek approval from the Trustee to sell and buy property. From the facts you listed above, it it is likely the Trustee would grant the request. You should contact your attorney to draft the proper motions.
*This answer is provided as general information, and is not to be construed as legal advice.
If you are in a Chapter 13, there is a prohibition against incurring debt without trustee or court permission. So, if you need to do so, you will need to seek that permission. If you are replacing a vehicle payment with a new vehicle payment then you may need to modify your Chapte 13 plan to show the old vehicle as a surrender, if possible, or to change the chapter 13 plan payment to reflect the difference. Some trustees require a new budget to be filed when seeking permission to take on a new debt. Talk with your attorney to find out what is required.
The information provided herein is for general informational purposes and not to be relied upon as a substitute for legal advice with regard to your unique set of circumstances. Futher, the answer provided herein does not establish an attorney-client relationship and I would advise any contemplating a bankruptcy to meet with a qualified attorney licensed in their respective geographical location.