How long does a full transmission rebuild take?

In most cases, a full transmission rebuild takes about 1 to 5 days for automatics, and roughly 1 to 2 days for manuals, assuming parts are in stock. Real-world timelines vary with model, parts availability, and any issues uncovered during teardown.

The question isn't just about hours; it involves the scope of work, access to the unit, and the shop's workload. A rebuild includes teardown, inspection, replacement of worn components, reassembly, testing, and sometimes software updates or auxiliary repairs. Vendors may hold parts, causing delays; some vehicles require engine or drivetrain removal to access the transmission.

Estimated timeframes by transmission type

Below is a breakdown by transmission type showing typical labor hours to complete a full rebuild.

Manual transmissions

Manual units are often simpler in design but require precise fitting and syncing. The following labor segments cover the main steps and typical clock time.

• Tear down and inspection: 2–4 hours


• Component replacement (gears, bearings, synchros, seals, forks, and clutch packs where applicable): 8–16 hours


• Reassembly and adjustments (clearances, end play, gear backlash): 6–8 hours


• Fluids, seals, and final checks: 2–4 hours


• Road test and final verification: 1–2 hours

In total, manual rebuilds typically amount to roughly 19–34 labor hours, equating to about 2–4 days of work for a shop running standard 8-hour days. Real-world calendar time can extend if parts are delayed or additional issues are found.

Automatic transmissions

Automatics carry more complexity due to the hydraulic and electronic control systems. The main steps and their typical time ranges are listed here.

• Tear down and inspection: 4–8 hours


• Internal component replacement (clutches/bands, gears, drums, torque converter, bearings): 12–20 hours


• Valve body/controls and electronics work (solenoids, pressure switches, TCM programming): 4–12 hours


• Reassembly and alignment (case sealing, external connections): 6–8 hours


• Fluid fill, cooler lines, and testing: 2–4 hours


• Road test and debugging/shifting adjustments: 1–2 hours

Automatic rebuilds typically run about 30–60 labor hours, which can translate to roughly 4–7 business days of work, with longer calendar timelines if parts must be ordered or if the shop is busy.

What can influence the timetable

Several factors can push a rebuild beyond the usual range. The following are the most common variables that affect calendar time.

• Transmission model and complexity: newer or more sophisticated units with additional sensors and controls take longer to service.


• Parts availability: back-ordered gears, seals, or valve bodies can add days or even weeks in rare cases.


• Condition found during teardown: cracked housings, worn gears, or damaged shafts can require bigger repairs or replacements.


• Drivetrain configuration and access: AWD, 4WD, or tight engine compartments can complicate removal and reinstallation.


• Engine/transmission removal: some vehicles require engine or subframe removal to reach the trans, adding labor.


• Software updates and adaptations: modern automatics may need TCM re-flashing or calibration, which adds time.


• Shop workflow and backlog: during busy periods, a rebuild may wait for a bay or technician.


• Whether a remanufactured unit is chosen: some customers opt for a full reman with a warranty, which can shorten or lengthen timelines depending on supply chains.

Understanding these variables helps set realistic expectations when requesting quotes or scheduling service.

Summary

In practical terms, most full transmission rebuilds fall within a few days for manuals and up to about a week for automatics, assuming parts are available and no major surprises appear. For an accurate timeline, consult a trusted shop with your vehicle’s exact make, model, and symptoms; they can provide a detailed estimate based on teardown findings and part availability.

What to expect after a transmission rebuild?

After a transmission rebuild, you can expect improved performance, smoother shifting, and better fuel efficiency once any initial break-in period is complete. It's crucial to follow the shop's break-in instructions, which typically involve avoiding heavy loads for several hundred miles. You should also watch for warning signs like slipping, grinding, or fluid leaks and have the transmission re-checked by the shop after about 10 days to ensure minor issues are caught early. 
During the break-in period (typically first few hundred miles) 

• Avoid aggressive driving: Stay away from heavy towing, excessive speeds, or harsh acceleration to let the new components adjust slowly. 
• Drive with a variety of speeds: Instead of long highway drives, vary your speeds with gentle acceleration and deceleration to help the clutches and bands seat properly. 
• Allow for cooling: Avoid prolonged use at once. Let the transmission cool down after extended driving to prevent overheating. 

After the break-in period

• Smoother shifting: Your car should shift more smoothly and have improved overall driveability. 
• Better acceleration and efficiency: A properly rebuilt transmission can lead to better acceleration and potentially improved fuel economy. 
• A 10-day recheck is recommended: Bringing the vehicle back to the shop for a checkup allows technicians to inspect for minor issues like leaks or improper adjustments before they become major problems. 

What to watch for

• Slipping gears: Be alert for gears that feel like they are struggling to engage or are slipping out of gear. 
• Unusual noises: Listen for new grinding, whining, or clunking sounds. 
• Delayed engagement: A noticeable lag when shifting from park to drive or reverse can be a sign of a problem. 
• Burning smell: This indicates that the transmission fluid may be overheating. 
• Fluid leaks: Any sign of fluid leaking from the transmission should be addressed immediately. 
• Check Engine light: If your check engine light comes on, have the vehicle inspected, as it could be related to the transmission. 

Long-term maintenance

• Regular fluid checks: Periodically check transmission fluid levels and quality. 
• Follow maintenance schedule: Adhere to the recommended service schedule for your vehicle, including regular transmission fluid changes. 
• Drive within your vehicle's limits: Avoid towing or carrying loads that exceed your vehicle's rated capacity. 

How long does it take to fully rebuild a transmission?

three to five days
Transmission Rebuilds
A rebuild is labor-intensive, as the tech must disassemble, inspect, and replace damaged components. Plan on anywhere from three to five days for a proper rebuild. The exact timeline depends on factors such as transmission condition and part availability.

What does a full transmission rebuild include?

A transmission rebuild consists of completely disassembling the transmission, thoroughly cleaning all components, and replacing worn or damaged parts with new or refurbished ones. The process includes inspecting, repairing, and reassembling the transmission with new gaskets, seals, clutch packs, and potentially new drums, before reinstalling it.
 
This video demonstrates the step-by-step process of rebuilding an automatic transmission: 58sPOWERNATION 2YouTube · Nov 3, 2021
1. Diagnosis and removal

• A certified technician performs a thorough diagnosis to determine the extent of the damage. 
• The transmission is removed from the vehicle for the rebuild to begin. 

2. Disassembly and cleaning

• The transmission is completely taken apart, down to its individual components. 
• Each part is then meticulously cleaned to remove all dirt and debris. 

3. Component inspection and replacement

• All parts are carefully inspected for wear and damage. 
• Commonly replaced parts include:
  • Gaskets and seals: These are replaced to prevent fluid leaks. 
  • Clutch packs and bands: These are replaced to ensure proper gear engagement. 
  • Valve body and solenoids: These may need to be cleaned, or replaced if damaged, to regulate fluid flow. 
  • Drums: These are replaced if they are damaged, and can sometimes be rebuilt with new rings. 

4. Reassembly and testing

• The transmission is reassembled with the new or refurbished parts. 
• After reassembly, technicians perform checks, such as applying air pressure to test for proper movement of components like the drums. 
• The transmission is then refilled with new fluid. 

This video explains the importance of rebuilding certain parts of a manual transmission: 59sObscure MotorsportsYouTube · Dec 5, 2019
5. Reinstallation

• The rebuilt transmission is reinstalled into the vehicle. 

This video explains the process of rebuilding a manual transmission from a junkyard core: 58sUncle Tony's GarageYouTube · Apr 17, 2024

Can you rebuild a transmission in 2 days?

How long does a transmission rebuild typically take? A transmission rebuild usually takes between 2 to 4 days, depending on the severity of the damage and the availability of replacement parts.