it's making a loud grinding noise from the right side every time it prints or copies.

Diagnosis

The loud grinding noise emanating from the right side of the HP OfficeJet Pro 8135e is typically caused by a mechanical failure in the carriage drive system or a misalignment in the paper feed assembly. Specifically, this occurs when the carriage gear (located on the right side of the chassis) loses synchronization with the drive belt, or when the paper feed rollers are slipping against a worn separation pad. When the rollers cannot grip the paper firmly, the motor continues to spin, causing the plastic drive gears to "chatter" or grind against one another under tension. To confirm the source, open the ink cartridge access door and watch the carriage move. If the noise happens only when the carriage moves from left to right, the issue is the carriage drive gear or a foreign object (like a staple or scrap of paper) lodged in the right-side rail. If the noise occurs only during the initial paper pull, the culprit is the feed roller assembly and the separation pad, which are failing to create enough friction to move the media, leading to gear slippage.

How to Fix It

If the noise is linked to the paper feed system, you must replace the worn components to restore grip and silence the gears.

1. Power down the printer completely and disconnect the power cable from the wall outlet to prevent electrical shock or carriage movement during service.
2. Remove the main paper tray entirely from the chassis. Reach inside the tray cavity and use a flashlight to check for any jammed scraps of paper or foreign debris near the right-side pickup roller.
3. Locate the feed roller assembly. Using a lint-free cloth dampened with distilled water, wipe the rubber rollers to remove paper dust and ink buildup. If the rubber feels smooth or "glazed," it must be replaced.
4. Order the HP Maintenance Kit (Part CF400-67932). This kit includes the high-friction separation pad and the pickup rollers.
5. Remove the old separation pad by gently prying it from its housing using a plastic spudger or a flat-head screwdriver.
6. Press the new separation pad firmly into the housing until it clicks into place. Ensure it is flush against the frame to prevent skewed feeding.
7. Slide the new rollers onto the drive shafts, ensuring the gear teeth are perfectly aligned with the drive motor on the right side.
8. Reinsert the paper tray, plug in the printer, and run a "Print Quality Diagnostic" page to verify the noise has ceased.

If That Didn't Work

• Clear the Carriage Path: Open the ink access door and manually slide the carriage to the far right. Check the plastic gear assembly for any chipped teeth or debris. Use a can of compressed air to blow out the right-side rail and gear housing to remove any accumulated dust or hair that could be causing the motor to strain.
• Lubricate the Carriage Bar: If the noise is a high-pitched grind, the carriage bar may be dry. Apply a tiny amount of synthetic white lithium grease to the metal guide rail. Move the carriage manually from left to right several times to distribute the lubricant evenly.
• Perform a Hard Power Reset: Sometimes the carriage positioning sensor gets "confused," causing the motor to over-drive the gear. Unplug the power cord from the back of the printer while it is still ON. Wait 60 seconds, then plug it back in. This forces the printer to re-home the carriage and recalibrate the gear timing.
• Check for Paper Jam Fragments: Use a flashlight to inspect the rear duplexer area. A small piece of torn paper lodged in the right-side exit sensor can cause the rollers to spin against a blockage, creating a grinding sound that mimics a gear failure.

Heads Up

• Avoid using rubbing alcohol on the feed rollers; it can dry out the rubber and cause them to crack, leading to more frequent jams.
• Always use high-quality, 20lb to 24lb bond paper. Using overly thick cardstock or very thin glossy paper can put excessive strain on the plastic drive gears.
• Ensure the paper guides in the tray are snug against the paper stack. If the paper is loose, it can enter the feed mechanism at an angle, causing the gears to grind during the pull.
• Regularly update the printer firmware via the HP Smart app to ensure the carriage movement logic is optimized for the latest hardware revisions.