Wranglers bring in a specific type of customer — often someone who wheels the vehicle hard and has already read three forum threads before walking through your door. The symptoms they describe can be accurate or completely off-base. Here are the three misdiagnoses that cost shops time on this platform. 1. "Clunking when engaging 4WD, especially 4-Lo" — misdiagnosed as transfer case failure. On the JK with the 42RLE, a clunk during 4WD range engagement is frequently the transmission's underdrive clutch pack, not the NV241 or NV241OR transfer case. Here's why: 4-Lo engagement requires the transmission to be in Neutral momentarily while the transfer case shifts. If the underdrive clutch pack is dragging — partially applied even in Neutral — it creates a bind when the transfer case tries to engage low range, and the resulting clunk gets attributed to the t-case. Test it: with the truck in Neutral, transmission in Park, does the 4-Lo engagement feel different than when the engine is off? If it's smoother with the engine off, the transmission is dragging in the fluid circuit. Check underdrive clutch pack apply pressure and accumulator condition before touching the transfer case.
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