VFD Machined Front Gear Set: Install and Break-In Guide

Quick answer

Install the VFD Machined Front Gear Set by opening the transmission, removing the old gears, and pressing the new 52T lower and 23T top gears onto their shafts. Set gear mesh with a small amount of backlash, then break in with short low-throttle runs before full crawling.

Tools and parts you'll need

Gather a cross wrench (often included with your kit), hex drivers, and a clean work surface. The VFD Machined Front Gear Set includes the 52T lower and 23T top gears. If you're also replacing the slipper, the VFD Slipper Set is a direct replacement for the VFD Twin transmission and an option for the standard VFD in the VS4-10 Pro, Ultra, or VPS10152 kit.

Step 1: Remove the transmission

Disconnect the driveshafts and unbolt the transmission from the chassis. Keep screws organized by location. This prevents mixing thread lengths, which can strip plastic or aluminum housings during reassembly.

Step 2: Open the case and remove old gears

Separate the transmission halves and lift out the old front gears. Note the orientation of the 52T lower gear and 23T top gear. Wipe out old grease and inspect the case for debris or wear.

Step 3: Install the new gear set

Slide the 52T lower gear onto its shaft, then the 23T top gear. These are machined steel 48-pitch gears designed for any VFD or VFD Twin transmission. Press them on squarely; do not force them. A small amount of grease on the teeth helps initial assembly.

Step 4: Set gear mesh and slipper

With the case closed but screws snug, check backlash between the gears. You want a tiny amount of rock, not tight binding. If you're using the VFD Slipper Set, tighten the M4 locknut down and then back off 1/2 turn to approximate 60 oz/in torque. This protects the drivetrain during break-in.

Step 5: Break-in procedure

Run the truck at low throttle on a stand or smooth surface for 2-3 minutes, then let it cool. Repeat 2-3 times. This seats the gear teeth without heat spikes. Avoid full-throttle launches or heavy crawling until break-in is complete.

Step 6: Final check and re-grease

After break-in, open the case and check for metal dust or unusual wear. Re-grease with a quality plastic-safe grease. Recheck slipper torque if equipped. Then reassemble and test on a low-speed course before your next run.

Installation steps with checkpoints

1. Remove transmission: Unbolt from chassis and disconnect driveshafts. Keep screws organized. Checkpoint: label or sort screws to avoid mismatched lengths.
2. Open case and remove old gears: Separate halves, lift out old gears, and clean the case. Checkpoint: inspect for debris or worn bearings before installing new gears.
3. Install new gear set: Press 52T lower and 23T top gears onto shafts squarely. Checkpoint: do not force gears; they should slide on with light pressure.
4. Set mesh and slipper: Adjust backlash to a small amount of rock. Set slipper by tightening M4 locknut then backing off 1/2 turn. Checkpoint: spin gears by hand—they should turn freely without binding.
5. Break in: Run at low throttle for 2-3 minutes, cool, repeat 2-3 times. Checkpoint: stop if transmission gets hot or makes grinding noise.
6. Final check and re-grease: Open case, inspect for wear, re-grease, and recheck slipper torque. Checkpoint: test on a low-speed course before full crawling.

Product facts

• VFD Machined Front Gear Set: VFD Machined Front Gear Set includes one 52T 48P lower gear and one 23T 48P top gear. These are the first two gears inside the transmission, so correct installation and mesh are critical for reliability.
• VFD Slipper Set: VFD Slipper Set is a direct replacement for the VFD Twin transmission and an option for the standard VFD in VS4-10 Pro, Ultra, or VPS10152. A properly set slipper protects the new gear set from shock loads during break-in and normal crawling.