Redcat RER31799 Problems: Troubleshooting and Fixes

By Redcat Racing | Published: 2026-11-03

Category: Tips & Care

Diagnose common RER31799 underdrive gear set issues in ASCENT FUSION and EVEREST ASCENT vehicles, from noise and binding to wear, with clear fix-or-stop rules.

Quick answer

Most RER31799 problems trace to installation error, worn mating gears, or debris in the transmission. Start by checking mesh and cleanliness, then replace the set if teeth are visibly worn or chipped.

Why this gear set is different from a stock replacement

The RER31799 is a transmission underdrive gear set, not a direct stock replacement. Underdrive gearing changes the ratio, so you should expect different acceleration and top-speed behavior. If you are troubleshooting a vehicle that already has this set installed, compare against the stock setup only if you know the vehicle ran correctly before the swap. Otherwise, treat any new noise or binding as an installation or wear issue first.

When to stop diagnosing and replace

Stop adjusting and replace the set when you find chipped, cracked, or heavily polished teeth, or when the gear spins freely on its shaft. These are not fixable by shimming or cleaning. Also stop if the transmission housing is cracked or the bearings are rough—those are separate faults that a new gear set will not cure.

Symptom-to-fix diagnosis

Whining or grinding noise after install: Remove the transmission cover and inspect gear mesh. The underdrive set may sit slightly differently than stock; check that the gears are fully seated and that no shims are missing. Re-shim if there is visible play or tight mesh. If noise persists after correct shimming, check for worn bearings before replacing gears.
Binding or locked drivetrain: Disassemble the transmission and look for debris, melted plastic, or a misaligned gear. Clean all parts and confirm the gear set rotates freely by hand before reinstalling. Do not force the drivetrain. Binding that remains after cleaning and reassembly points to a bent shaft or damaged bearing, not the gear set.
Acceleration feels slower than expected: This is normal with an underdrive set—it trades acceleration for higher top speed. If the change is severe, verify you installed the correct gear set and that the rest of the drivetrain is stock. Revert to stock gearing if the vehicle is used mainly for tight tracks. Choose another ratio if low-speed torque matters more than top speed.
Teeth wear quickly or show flat spots: Inspect the mating gears and bearings for roughness or misalignment. Replace any worn bearings and ensure the transmission case is not deformed. Use the correct lubricant and avoid over-tightening the cover. If wear recurs within a few runs, stop using the set and check the entire drivetrain for a bent shaft or debris.
Gear set will not fit or rubs the housing: Confirm you have an ASCENT FUSION or EVEREST ASCENT vehicle. Check for leftover stock shims or spacers that may interfere. Do not modify the housing to force fitment. If fitment is unclear, consult your vehicle documentation or choose a stock replacement instead.

Product facts

RER31799: RER31799 is a steel transmission underdrive gear set supplied as one set for ASCENT FUSION and EVEREST ASCENT vehicles. Steel construction resists wear better than softer alloys, but it still needs correct mesh and clean lubrication to avoid noise and premature failure.
RER31799