Dell Precision T3400 (Late 2007) - Manual (Page 237)

Adding and Replacing Parts
237
5 Pull the drive retention insert out by the handle and set it aside in a safe
place.
6 Slide the drive out and remove it from the drive bay.
Installing an Optical Drive (Desktop Computer)
NOTICE:
In a desktop configuration with 3 hard drives, there can only be one
optical drive which must be installed in the upper 5.25-inch drive bay. In this case,
the 3rd hard drive will occupy the lower 5.25-inch drive bay.
1 If you are installing a new drive, unpack the drive and prepare it for
installation.
Check the documentation that accompanied the drive to verify that the
drive is configured for your computer. If you are installing an IDE drive,
configure the drive for the cable select setting.
1 drive retention insert 2 CD/DVD drive
1
2