Dell 2135cn Service Manual page 693

Chapter 3 Removal and Replacement Procedures (RRPs)
10) Move the ROLL CORE MSI to the right
side, to secure the hook of the ROLL
CORE MSI with the groove of the SHAFT
ASSY FEED.
Go to the next replacement step:
Replacement 28 KIT DRIVE ASSY PH (PL7.1.99)
3 - 191
Version 
2008.02.01