TonGass (2-Pack, Silver) Exact Replacement 4 7/8" Flat Idler Pulley 956-04129 Idler Pulley Compatible with Cub Cadet MTD, OEM Part Number 956-04129C, 756-04129B, 756-04129C, 753-08171

What It Is

This is an aftermarket flat idler pulley (4-7/8″ diameter, silver) that replaces OEM part 956-04129C. It guides and tensions the deck belt on select Cub Cadet and MTD zero-turn and lawn tractor mowers, typically on 42″ to 54″ decks.

Fitment & Compatibility

Before buying, verify your mower’s model number (found under the seat or on the frame) and check the OEM part number stamped on your old pulley. This pulley replaces Cub Cadet/MTD OEM numbers 956-04129, 956-04129C, 756-04129B, 756-04129C, and 753-08171. Measure the pulley diameter: it must be exactly 4-7/8″. Also confirm the center hole size (usually 3/8″ or 5/8″) and the bearing width—this unit uses a standard 6202-2RS bearing. Not compatible with decks requiring a 5″ or 5-1/2″ pulley.

Key Things to Know

• Build quality: Made of stamped steel with a sealed ball bearing. Most buyers report it matches OEM specs and runs smoothly, but a few note the bearing is slightly noisier than OEM.
• Installation: Simple swap—remove the old pulley’s center bolt or clip, install the new one, and retighten to 20–30 ft-lbs. No special tools needed.
• Common gotcha: The pulley may sit slightly higher or lower than the original if your deck has a spacer or bushing. Reuse any existing spacer or washer from the original setup.
• Pack includes two pulleys—handy if your deck uses two idlers or you want a spare. Check your deck diagram to confirm you need both.

Should You Buy It

If you need a direct-fit, cost-effective replacement for a worn or noisy idler pulley on a Cub Cadet or MTD with a 4-7/8″ flat pulley, this is a solid choice. It’s not premium-grade, but for the price and pack of two, it’s a reliable fix for most residential and light-commercial mowers.