How to Replace Engine Mounts on a 2018 GMC Sierra 1500 (Left & Right)
Step-by-step engine mount swap with required tools/parts, safety tips, and torque specs
How to Replace Engine Mounts on a 2018 GMC Sierra 1500 (Left & Right)
Step-by-step engine mount swap with required tools/parts, safety tips, and torque specs


đź”§ Sierra 1500 - Engine Mount Replacement
Your Sierra 1500 uses two engine mounts (left and right) to hold the engine in place and absorb vibration. Replacing worn mounts stops clunks on acceleration/braking, reduces vibration, and prevents drivetrain misalignment.
Difficulty Level: Advanced | Estimated Time: 3-6 hours
⚠️ Safety & Precautions
- 🧯 Support the truck with jack stands on the frame—never rely on a jack.
- 🔥 Let the exhaust cool fully; the mounts sit near hot components.
- đź§± When lifting the engine, use a wood block on the jack pad to spread the load and avoid oil pan damage.
- 🧤 Keep hands clear while raising/lowering the engine; mounts can “shift” suddenly.
- 🔋 Battery disconnect is not usually required for mounts, but disconnect the negative cable if you’ll be working near the starter/primary cables on the right side.
đź”§ Required Tools
You'll need the following tools for this repair:
- Floor jack (rated 3-ton minimum)
- Jack stands (rated 3-ton minimum)
- Wheel chocks
- Safety glasses
- Mechanic gloves
- Wood block (2x6 or 2x8)
- Socket set with ratchet (3/8" and 1/2" drive)
- 15mm socket
- 18mm socket
- 21mm socket
- Wrench set (15mm, 18mm)
- Breaker bar (1/2" drive)
- Torque wrench (10–200 ft-lbs range)
- Long extensions (6" and 12")
- Universal joint swivel adapter
- Trim clip tool
- Flathead screwdriver
- Work light
🔩 Required Parts
HowToo sells all the parts you need for this repair:
- Left engine mount - Qty: 1
- Right engine mount - Qty: 1
- Engine mount hardware kit - Qty: 1
đź“‹ Before You Begin
- 🅿️ Park on level ground, set the parking brake, and chock the rear wheels.
- 📏 Raise the front and support the frame with jack stands so the suspension can hang slightly (this helps clearance).
- 🛡️ Remove any front skid plate(s) if equipped using the appropriate socket (commonly 15mm socket).
- 🧱 Position a floor jack with a wood block under the engine oil pan area. You are only “taking the weight,” not lifting the truck. Lift slowly and watch for shifting.
🔨 Step-by-Step Instructions
Follow these steps in order:
Step 1: Confirm mount locations and create access
- From underneath, locate the left mount (driver side) and right mount (passenger side).
- Remove any splash shields blocking access using a trim clip tool and flathead screwdriver.
- Set your work light so you can clearly see the mount-to-frame bolts and the center fastener.
Step 2: Support the engine
- Place the floor jack (rated 3-ton minimum) with the wood block under the engine to support it.
- Raise the jack just until you see the engine “settle” slightly (weight supported). Do not crush the oil pan.
Step 3: Remove the left (driver-side) engine mount fasteners
- Loosen the mount’s main fastener (often a through-bolt/nut—this is the long bolt that passes through the rubber mount) using an 18mm socket and breaker bar.
- Remove the mount-to-frame fasteners using an 18mm socket, ratchet, extensions, and a universal joint swivel adapter as needed.
- If the mount/bracket is tight, lift the engine slightly with the floor jack to relieve tension and then continue removing fasteners.
Step 4: Remove the left engine mount
- Work the mount out through the best opening (usually downward and toward the rear) while adjusting engine height with the floor jack.
- If clearance is tight, remove nearby shield/bracket hardware using a 15mm socket only as needed.
Step 5: Install the new left engine mount (leave bolts loose first)
- Position the new mount in the same orientation as the old one.
- Start the mount-to-frame bolts by hand to prevent cross-threading, then snug with an 18mm socket.
- Start the main through-bolt/nut by hand, then snug with an 18mm socket and wrench set (18mm).
Step 6: Torque the left engine mount fasteners
- Torque mount-to-frame fasteners using a torque wrench: Torque to 75 Nm (55 ft-lbs).
- Torque the main mount through-bolt/nut using a torque wrench: Torque to 100 Nm (74 ft-lbs).
Step 7: Repeat removal and installation on the right (passenger-side) mount
- Support the engine the same way with the floor jack and wood block.
- Remove the right mount main fastener using an 18mm socket and breaker bar.
- Remove right mount-to-frame fasteners using an 18mm socket, extensions, and universal joint swivel adapter.
- Swap in the new right mount, start all fasteners by hand, then snug using an 18mm socket.
- Torque right mount-to-frame fasteners using a torque wrench: Torque to 75 Nm (55 ft-lbs).
- Torque the right main through-bolt/nut using a torque wrench: Torque to 100 Nm (74 ft-lbs).
Step 8: Reinstall shields/skid plates and lower the truck
- Reinstall any splash shields/skid plates using a 15mm socket (or the socket size you removed) and ratchet.
- Lower the engine support jack slowly using the floor jack.
- Lower the truck off the jack stands using the floor jack.
âś… After Repair
- 🔍 Start the engine and watch the engine movement in Park/Reverse/Drive with the brake held (normal is slight movement; clunking is not).
- 🛣️ Test drive and check for clunks on light acceleration/braking and over bumps.
- đź§° Recheck all mount fasteners after the test drive with a torque wrench.
đź’° DIY vs Shop Cost
Shop Cost: $600-$1,200 (parts + labor)
DIY Cost: $160-$450 (parts only)
You Save: $440-$750 by doing it yourself!
Shop labor rates vary but typically run $100-$150/hour. This repair takes a shop approximately 3-5 hours.
🎯 Ready to get started?
HowToo makes it easy: same-day/2-day shipping on every part, plus all the tools and specialty tools you need! Check out the parts and tools sections below to add everything to your cart.

















