jQuery Grid Plugin - jqGrid

We have not been frequently updating our jQuery or jqGrid versions. When trying to upgrade to the latest releases, I've discovered that setGridParam no longer works in my code. Since no one else seems to be having this issue, I am blaming my code, but cannot identify the problem.

When we were using jQuery 1.7.1 and jqGrid 4.4.1; all worked okay. I've tried a few versions of jQuery, and the issue seems to have started with the release of 1.8.3. Using that version and jqGrid 4.4.4; the data no longer shows in the grid. 

Here is a short bit of the program. trows is the JSON length returned from the $.ajax call. tdata is the JSON data. Stepping through a debugger, these values do exist when calling the jqGrid functions. Can someone point out what I may have missed in the release notes? Thanks.

$myTable

.jqGrid('clearGridData')

.jqGrid('setGridParam',

{

datatype: "local",

data: tdata,

rowNum: trows > 50 ? 50 : trows            

}

.trigger("reloadGrid");