First thing I notice is you named your calculated field in your Query 'Month'. This is a reserved word. Using it as a field name may cause problems later.

In your formula that isn't working, you are missing a couple of quotes:
=Nz(DSum("Cylinders", "AllFillCountQ", "DateFillMonth=""" & [MTD] & """"),0)

I changed the "Month" to M2 in the query, and updated the code as specified here. by adding the extra quotes. Now the sum calculates All Months. Such as All the February's into one total instead of Feb 2022 only.  As specified as such: =Nz(DSum("Cylinders","AllFillCountQ","M2="""&[MTD]&""""),0). The value for all year, month and quarter should read 29. As i have only 2 records 26 Feb 2022 = 14(Cylinders), and 27 Feb 2022 = 15(Cylinders). My year works perfectly, still not sure why:  
=Nz(DSum("Cylinders","AllFillCountQ","Year="&[YTD2]),0)  Thank you for your assistance

You could write it something like this which would sum up your values for the current month of the current year.
You could replace the Date() function with values from a field on your form.

=Nz(DSum("Cylinders","AllFillCountQ","DateFill=" & Month(Date()) & " And DateFill=" & Year(Date())),0)

Depending on your setup you may be able to replace the query name with the table name eliminating the need for the query.

Hi Kevin, I believe i have solved the issue. The month and Quarter could not figure out the year in question. For example Feb 2022, The code would select all Feb and calculate totals. So in the Query for M2(month) was formatted with "mmmm, yyyy" vice just "mmmm" , same with the quarter. Then when I applied the following code =Nz(DSum("Cyl2","AllFillCountQ","FillDate="""&[MTD]&""""),0) it would select the correct month from the fields on the form indicating the year, month and quarter. now it will calculate the selected month. To test this I changed my clock to a seperate set of fills, and the all calculated correctly. Thank you for your assistance.