Transmission Control Protocol (TCP) is implemented in the transport layer of a MANET, which enjoys the advantage of reliable data transmission over the Internet. However, due to certain unique characteristics of a MANET, modification of classical TCP has been done so as to improve its performance in such an environment. Accordingly, several MANET specific TCP versions like TCP Reno, TCP New Reno, TCP Tahoe and TCP Vegas have come into prominence. This paper evaluates the performance of the different TCP versions for the same network topology over certain fixed parameters like number of packets generated/node, average packet loss, average delay incurred by the packets while in transit from source to destination and the processing time taken by the intermediate nodes. For routing purpose, we have assumed Ad-Hoc On Demand Distance Vector Routing (AODV) as the standard. To address the common issues of congestion control as with TCP, the experiment has been carried out under different network loading conditions that have been achieved by slowly increasing the node density.