If oil isn’t dripping from beneath your Jeep TJ’s inline-six, it’s because it’s either brand new or the rear main seal has been replaced within the last 40,000 miles. That’s just a fact of four-liter ...

The rear main seal keeps oil sealed inside the rear of the engine, where the crankshaft connects with the transmission. It can be expensive to repair, often $600 or more, because it typically involves ...

To answer Mike’s questions, let us first return to the basics. A rear main seal, or crankshaft seal as it is commonly referred to, is a big, round rubber seal between the engine and transmission. The ...