Dell 2135cn Service Manual page 745

Chapter 3 Removal and Replacement Procedures (RRPs)
5) 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 57 PHD Unit (PL4.1.21)
3 - 243
Version 
2008.02.01