PACCAR TX-12 Transmission
Specs, gear ratios, oil change interval and warranty
PACCAR
The PACCAR TX-12 is a 12-speed automated manual transmission that PACCAR designed to work with its MX engines and axles. PACCAR rates it at 1,850 lb-ft and lists a system weight of 657 lb, including the clutch and oil. It holds 16 pints of oil, and PACCAR lists the first oil change at 750,000 miles. The warranty is 5 years or 750,000 miles for the transmission.
PACCAR published the PACCAR TX-12 figures in its own documents. Last reviewed November 3, 2026.
What are the PACCAR TX-12 specs?
| Type | Automated manual (AMT) |
|---|---|
| Speeds | 12 forward, 2 reverse |
| Torque capacity | 1,850 lb-ft |
| Maximum operating weight | 110,000 lb |
| System weight | 657 lb (transmission, clutch and oil) |
| Oil capacity | 16 pints |
| Lower cruise speed limit | 1,100 rpm |
| PTO | 8-bolt, bottom mount, up to 95 hp |
| Clutch | 430 mm self-adjusting, greaseless, maintenance free |
| Lubrication | Cooler-less precision lubrication, with a fluid pressure sensor that warns the driver of low oil |
Compare the PACCAR TX-12 with the others in the transmission specs reference, and see which truck it sits in on the truck model specs.
What should you check before you spec or buy a truck with the PACCAR TX-12?
- Check that the truck has the MX engine and the PACCAR axles the TX-12 was designed to work with.
- Ask whether the first oil change was done. PACCAR lists it at 750,000 miles. The spec sheet gives no separate interval for vocational or heavy-haul work, so ask a dealer.
- Confirm the warranty in writing for that truck. PACCAR lists 5 years or 750,000 miles for the transmission and 3 years or 350,000 miles for the clutch.
What is the TX-12 PRO?
PACCAR also sells a TX-12 PRO. Peterbilt's March 24, 2025 release says it supports up to 1,700 lb-ft with the MX-13 and is offered on the Peterbilt Models 579, 567 and 589. Peterbilt describes it for on- and off-highway work such as dump trucks and tankers. That page gives no weight, oil interval or warranty for the PRO, so the rest of this page covers the standard TX-12.
| Version | Torque stated by PACCAR | Where PACCAR lists it |
|---|---|---|
| TX-12 | 1,850 lb-ft torque capacity | PACCAR spec sheet and brochure |
| TX-12 PRO | Up to 1,700 lb-ft with the MX-13 | Peterbilt Models 579, 567 and 589 |
What are the PACCAR TX-12 gear ratios?
PACCAR TX-12 gear ratios
- Gear 114.43
- Gear 211.05
- Gear 38.44
- Gear 46.46
- Gear 54.95
- Gear 63.79
- Gear 72.91
- Gear 82.23
- Gear 91.70
- Gear 101.30
- Gear 111.00
- Gear 120.77
- Reverse 116.92
- Reverse 212.95
PACCAR's brochure lists an overall ratio of 18.85.
What fluid does the PACCAR TX-12 use, and how often do you change it?
PACCAR's spec sheet and brochure give the TX-12's oil amount, but they do not name an oil type. Use the oil in the service manual or ask a PACCAR dealer.
| Oil capacity | 16 pints |
|---|---|
| Oil type | Not named in the spec sheet or brochure |
| Lubrication system | Cooler-less precision lubrication |
| Low-oil warning | Fluid pressure sensor that alerts the driver to low oil |
PACCAR lists one oil change interval for the TX-12 and calls it the longest for linehaul work.
| Duty cycle | Interval |
|---|---|
| First transmission oil change | 750,000 miles |
| Clutch | Maintenance free (self-adjusting, greaseless) |
- PACCAR says the input shaft wear sleeve can be replaced quickly, without a full teardown.
- PACCAR's brochure says the TX-12 uses nearly half the oil of similar transmissions and shows clutch life prognostics, which help plan clutch replacement.
- The spec sheet gives one interval and does not split it by duty. Ask a dealer what applies to vocational or heavy-haul work.
Put your PACCAR TX-12 service on a schedule with the maintenance scheduler. If a warning light comes on, decode it with the fault code lookup.
What warranty does the PACCAR TX-12 have?
Warranty, as the maker lists it
- Transmission: 5 years or 750,000 miles
- Clutch: 3 years or 350,000 miles
- The brochure also lists extended protection plans.
Which engines and trucks go with the PACCAR TX-12?
PACCAR says it designed the TX-12 from the ground up to work with PACCAR MX engines and axles. Our truck models list shows it behind the MX-13 in the Peterbilt 579 and the Kenworth T680.
Fitted in the Peterbilt 579 and Kenworth T680.
What PACCAR claims
- PACCAR says the TX-12 weighs 105 pounds less than comparable automated transmissions and is the lightest transmission in its class.
- PACCAR says it has the longest oil change interval for linehaul work and the deepest reverse ratio among linehaul transmissions.
What is not published about the PACCAR TX-12?
- The oil type or viscosity
- A different interval for vocational or heavy-haul work
- Weight, oil interval and warranty for the TX-12 PRO
- A price. PACCAR sells it as part of the truck's spec.
There is no public, independent failure-rate data for any heavy-duty transmission, including the PACCAR TX-12. This page does not rank reliability. It lists what the maker publishes: ratings, ratios, fluid, service intervals and warranty. For a used truck, ask for the service records and check the oil and clutch history.
How does the PACCAR TX-12 compare with other transmissions?
Each transmission guide on this site follows the same format and the same sourcing rule, so you can read the PACCAR TX-12 next to the others. We do not name a winner.
- Eaton Cummins EndurantAutomated manual, 11-, 12- or 18-speed
- Detroit DT12Automated manual, 12-speed
- Volvo I-ShiftAutomated manual, 12-, 13- or 14-speed
Side-by-side comparisons with the PACCAR TX-12
PACCAR's TX-12 spec sheet and Eaton Cummins's Endurant HD page publish the same ratio table, the same 657 lb weight, the same 16 pints of oil and the same 1,850 lb-ft rating. Neither company's pages explain how the two are related, so this site does not say.
PACCAR TX-12 frequently asked questions
What oil does the PACCAR TX-12 use?+
PACCAR's TX-12 spec sheet and brochure do not name an oil type. They say it holds 16 pints. Look in the PACCAR service manual or ask a PACCAR dealer for the approved oil before you buy any.
How much oil does a TX-12 hold?+
PACCAR lists 16 pints for the TX-12. The brochure says that is nearly half of what similar transmissions need. The 657 lb system weight in PACCAR's spec sheet includes the transmission, clutch and oil.
How often do you change the oil in a PACCAR TX-12?+
PACCAR lists the first oil change at 750,000 miles and calls it the longest interval for linehaul work. The clutch is self-adjusting and maintenance free. PACCAR's sheet gives no separate interval for vocational use, so ask a dealer if your truck works off the highway.
What is the PACCAR TX-12 warranty?+
PACCAR's brochure lists 5 years or 750,000 miles on the transmission and 3 years or 350,000 miles on the clutch. It also mentions extended protection plans. Confirm the terms in your truck's written warranty.
What are the TX-12 gear ratios?+
First gear is 14.43 and twelfth is 0.77. The ratios in between are 11.05, 8.44, 6.46, 4.95, 3.79, 2.91, 2.23, 1.70, 1.30 and 1.00. Reverse is 16.92 and 12.95. PACCAR lists an overall ratio of 18.85.
Is the PACCAR TX-12 any good?+
No independent failure study exists for the TX-12. The published facts are a 1,850 lb-ft rating, a 110,000 lb maximum operating weight, a 750,000-mile first oil change and a 5-year, 750,000-mile warranty. For a used truck, ask for the oil change history and whether it has the standard TX-12 or the lower-rated TX-12 PRO.
Sources for the PACCAR TX-12
Run a PACCAR TX-12 truck? Let a dispatcher handle the rest.
Grow Trucking finds loads, negotiates rates and does the paperwork for owner-operators and small fleets. Tell us about your PACCAR TX-12 truck and we will show you how we can help.
Also: About Grow Trucking · Refer a carrier · Trucking blog
Ratings, intervals and warranty terms for the PACCAR TX-12 change by model year and configuration. Confirm the exact figures for a specific truck against PACCAR's current documents and your written warranty before you make a purchase or maintenance decision.
Free tools for a PACCAR TX-12 truck
Keep the PACCAR TX-12 serviced on time, decode its fault codes and check a truck before you buy.
- Preventive Maintenance SchedulerTrack PACCAR TX-12 oil changes by odometer for your duty cycle.
- Diesel Fault Code Lookup (SPN/FMI)Decode the SPN/FMI fault codes the PACCAR TX-12 reports.
- Breakdown Cost EstimatorEstimate what a PACCAR TX-12 breakdown costs in repairs and lost revenue.
- Used Truck Inspection ChecklistCheck the PACCAR TX-12 and clutch before you buy a used truck.