Attach WinDbg x64 or x86 (based on architecture of workflow server) File->Attach to a Process
when finished, it is VERY important to stop windbg by going to Debug->Detach Debuggee. When finished, copy the file c:\workflow_mem.log to us. (Or whatever the file ends up being named). The following commands can be copied and pasted into the windbg window all at once. The last line will say 'Closing open log file'. 

.loadby sos clr
.logopen c:\workflow_mem.log
!GCInfo
!DumpHeap -stat
!DumpHeap -stat -type Laserfiche 
!HeapStat
!EEHeap -gc
!FinalizeQueue
!threads
!EEVersion
!ProcInfo
!DumpDomain
.logclose

Windows Debugging Tools used to be a standalone download from Microsoft, but now they rolled them into the 1GB download for the Windows Drivre Kit. You can still find the standalone install at http://www.codemachine.com/resources.html