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A gearbox overhaul at Route 66 Auto Repair in Upland is the full answer for a manual transmission with more than one internal problem: noise in several gears, grinding shifts, and a gear that pops out under load. The gearbox is removed, taken apart, cleaned and measured, and worn bearings, synchronizers, seals and damaged gears are replaced. Your written estimate shows every step, and we photograph what we find.
When does a manual gearbox need an overhaul?
One worn part can sometimes be fixed alone. An overhaul makes sense when the symptoms point to more than one: a growl that changes with gear plus grinding into third, or a gear that jumps out while you climb toward the Cajon Pass. Jumping out of gear usually means worn gear teeth, shift fork pads or detents, and it tends to come with bearing wear that lets the shafts move.
Before we recommend it, we rule out simple causes. A clutch that does not fully release causes grinding in every gear. Broken engine or transmission mounts let the shifter move and pull a gear out. Low or incorrect gear oil makes shifts notchy and noisy. Our clutch system inspection checks those first.
What gets replaced in an overhaul?
- Input, output and countershaft bearings
- Synchronizer rings and, where worn, sleeves and hubs
- Seals and gaskets, including the input and output shaft seals
- Shift fork pads and worn detent parts
- Gears with chipped or pitted teeth, when found
- Gear oil that matches the maker's specification
Our gearbox overhaul process
Step 1: Confirm the gearbox is the source
Road test in each gear, mount check and clutch release test.
Step 2: Remove and tear down
The gearbox comes out and is disassembled and cleaned.
Step 3: Measure and photograph
Bearings, synchronizers, gears and endplay are checked, and findings are photographed.
Step 4: Updated estimate
If teardown finds more than expected, we stop and call you before going further.
Step 5: Reassemble and verify
The gearbox is rebuilt to spec, installed, filled and road tested in every gear.
What's included in a gearbox overhaul
Included on the work order
- 01Removal and installation
- 02Teardown, cleaning and measurement
- 03Bearings, synchronizer rings and seals
- 04Correct gear oil
- 05Photos of worn parts
- 06Road test through every gear
Need-now or need-later?
Need now: call
- A gear that jumps out under load
- Loud grinding or clunking with metal in the oil
Need later: book
- A faint whine in one gear with clean oil
- Slight notchiness only when cold
How pricing and timing work
The estimate is built in two parts: removal and teardown, then the parts the inspection proves are needed. Parts availability for your gearbox sets much of the timeline. If the clutch is worn, doing a clutch repair at the same time saves repeat labor, and we list it as a separate line so you can choose.
Aftercare
Shift smoothly and avoid hard launches for the first few hundred miles while new parts settle. We recheck the oil level and look for leaks at a follow-up visit. Warranty coverage is written on your invoice. If a single noise returns later, our gearbox bearing replacement page explains how we isolate it.
Frequently asked questions
Is an overhaul better than a replacement gearbox?
It depends on parts availability, the condition of the case and gears, and timing. We explain both options once we know what is worn, and the choice is yours.
Why did my gearbox start jumping out of gear?
Worn gear teeth, shift fork pads or detents are common causes, and broken mounts can make it worse. We check the mounts first, since that repair is simpler.
Should I replace the clutch at the same time?
If the clutch has meaningful wear, yes, because the gearbox is already out. If it is in good shape, we will say so and you can skip it.