Consolidating 12 worksheets with 5000+ rows in each

[MARKSTRO]

I have tried the pivot table wizard to consolidate worksheets, not sure if I've reached a threshhold with that many rows over that many worksheets.
Can anyone either point me in the right direction or ask me some questions to help me with this.
The data are monthly fuel entries for a fleet of trucks, one sheet per month, column A-I.
Column A is the drivers employee number, appearing multiple times throughout the month, should I or can I filter each sheet prior to condolidating?
I have many more columns in my pivot table beyond I with numerous duplicated column headings.
I have tried multiple and single page fields as well.
Much thanks for any support.

[JieJenn]

Are you using Excel 2003 or 2007? If you are using Excel 2007+, in the Data Ribbon, there is a Consolidate function, which just might be what you're looking for.

[MARKSTRO]

It looked like I used that function to build my pivot table, if I use that would it be independent of pivot table consolidation?