The Jeep Wrangler is an iconic off-road vehicle. But through the years, the various models haven’t always had the best manual transmissions. For example, the Jeep YJ (1987-1995 model years) and Jeep TJ (1997-2006) lacked a decent First gear ratio, and owners found the transmissions to be less durable once larger tires and weight were added to the Jeep, including heavier axles and other off-road equipment. The factory NSG370 6-speed transmission found in the Jeep JK (2007-2018) was better, but there was still room for improvement in the eyes of Wrangler enthusiasts. The superior First gear ratio and incredible strength of the TREMEC TR-4050 5-speed manual transmission has made it a desirable upgrade not only for the Jeep Wrangler, but also many other light trucks and 4×4 SUVs.
TREMEC TR-4050 5-speed Gear Ratios
The TREMEC TR-4050 5-speed was specifically built for light- and medium-duty trucks and 4x4s. With First through Fifth gears of 6.16, 3.11, 1.71, 1.00, .076 and a 6.03 Reverse gear, the TREMEC TR-4050 has a torque input rating of 600 lb-ft (more than twice the torque rating of factory transmissions found in 2018-and-earlier Jeep Wranglers).
|Transmission||1St Gear Ratio||2nd Gear Ratio||3rd Gear Ratio||4th Gear Ratio||5th Gear Ratio||6th Gear Ratio||Reverse Gear Ratio||Torque Rating|
|TREMEC TR-4050||6.16:1||3.11:1||1.71:1||1.00:1||0.76:1||N/A||6.03:1||600 lb-ft|
|Aisin AX15||3.83:1||2.33:1||1.44:1||1.00:1||0.79:1||N/A||4.22:1||Up to 300 lb-ft depending on configuration|
What Makes the TREMEC TR-4050 So Strong?
All forward gears in the TREMEC TR-4050 are fully synchronized using carbon friction material single- and double-cone synchronizers. For strength and increased internal stability, the input, main and counter shafts use tapered roller bearings. The TREMEC TR-4050 uses standard, readily available Dexron III/Mercon fluid for lubrication. A bonus is that the TREMEC TR-4050 also has a power take off (PTO) accessory port. The TREMEC transmission can be mated to a variety of original equipment and aftermarket transfer cases, including the Atlas from Advance Adapters.
Swapping in a TREMEC TR-4050
In addition to its strength and smooth shifting, the TR-4050 has a more compact design than the NSG 370. This means there won’t be clearance issues inside the factory transmission tunnel. Multiple shifter locations also eliminates extensive modifications to the transmission tunnel when swapping the TREMEC TR-4050 into many older 4x4s. The shorter overall length of the TREMEC TR-4050 also makes it ideal for short-wheelbase 4x4s, such as the early Jeep CJ and first-generation Ford Bronco.