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New Venture NV3550 manual (5-speed)

The five-speed that replaced the AX-15

When the Aisin AX-15 retired, its spot behind the 4.0 was taken by the New Venture NV3550: another five-speed manual, with a well-ribbed aluminum case and a more modern shift feel. It was the manual of the Wrangler TJ and the last Cherokee XJs.

The AX-15's heir

New Venture Gear —the GM–Chrysler joint venture that built gearboxes and transfer cases— produced the NV3550 as a direct replacement for the AX-15. It reached the TJ in 2000 and also equipped the XJ in its final two years (2000–2001), always behind the 4.0. It was built through 2004, when in the Wrangler it gave way to the six-speed NSG370.

It shares so much with the AX-15 that swapping one for the other is nearly direct: the same nine bellhousing bolts, the same clutch fork and throwout bearing, the same input-shaft length. That's why many treat them as interchangeable in practice.

Practical notes and faults

The NV3550 weighs about 97 kg (300 ft·lb stock torque rating), with an aluminum case and a removable straight-six bellhousing. Its first-gear ratio is short (4.01) and fifth is a proper overdrive (0.78), a good compromise between climbing and relaxed cruising. It's smoother and quieter than the AX-15, though purists still favor the Japanese box's unbreakable reputation.

Its known weak point is fifth gear and the odd synchro under hard use; maintenance, as always, comes down to the right fluid on schedule. Anyone chasing maximum strength for a serious build tends to jump to truck boxes (NV4500, SM465, T18).

Specifications