Under 29 CFR 1910.178(a)(4), OSHA requires that users get the manufacturer’s prior written approval for modifications and additions that affect capacity and safe operation of a forklift. Further, 1910.178(a)(5) requires that if the truck is equipped with front-end attachments other than factory installed attachments, the user must request that the truck be marked to identify the attachments and show the approximate weight of the truck and attachment combination at maximum elevation with load laterally centered. Also, a 07/03/2002, “Powered industrial truck addition/modification approval and marking requirements,” and 03/30/2004, “Written approval requirements for powered industrial truck modifications and additions that affect capacity or safe operation,” Letters of Interpretation provide additional information on this issue.