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Heavy-Duty Truck Transmission Parts

Keep your Class 8 trucks shifting and on the road with heavy-duty truck transmission parts built for over-the-road and vocational duty. JAK'S Diesel stocks rebuild and service components for manual heavy-duty truck transmissions: shafts, gears, synchronizers, bearings, seals, shift forks, and gaskets.

Not sure of the exact part on your unit? Give us the transmission make and model or the number stamped on the case and we will cross-reference OEM, competitor, and superseded numbers to get you the right component. Most orders ship same-day, with free freight over $1,000.

376
Parts Available
Showing 24 of 376 Heavy-Duty Truck Transmission Parts
CUP
JAK'S JAKS-EM89690
Available · Confirm Lead Time
$15.99
INSERT VALVE
JAK'S JAKS-EF36590
Available · Confirm Lead Time
$25.99
CUP
JAK'S JAKS-GCU-6036-TIM
Available · Confirm Lead Time
$16.99
CUP
JAK'S JAKS-GCU-6034-TIM
Available · Confirm Lead Time
$18.99
RETAINER
JAK'S JAKS-GBR-6095OEM
Available · Confirm Lead Time
$128.99
SLAVE VALVE KIT
JAK'S JAKS-GBK-3986
Available · Confirm Lead Time
$38.99
Eaton CUP
JAK'S JAKS-ER60360
Available · Confirm Lead Time
$3.99
PINION GEAR
JAK'S JAKS-EM67230
Available · Confirm Lead Time
$141.99
MAINSHAFT GEAR
JAK'S JAKS-EM64750
Available · Confirm Lead Time
$289.99
MAINSHAFT GEAR
JAK'S JAKS-EM64730
Available · Confirm Lead Time
$286.99
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Choosing the Right Heavy-Duty Truck Transmission Parts

Heavy-duty diesel components must be matched to the exact engine and application. Before ordering from this collection, verify the part number, engine model, engine serial number, and any casting or calibration number shown on the original component.

Fitment information to have ready

  • OEM, dealer, casting, or interchange part number
  • Engine manufacturer, model, and engine serial number (ESN)
  • Truck year and model when the component is chassis-specific
  • Core details for remanufactured or exchange components

Need a fitment check?

Use the OEM cross-reference tool or text a clear photo of the part tag to (720) 445-6249. A JAK'S Diesel specialist can confirm the match before the part ships.

Can't Find the Right Part?

Text us the part number or a photo of the tag — we'll cross-reference it and quote you the right one.