1998 Frontier 4x4 Clutch replacement cost

Somewhere in the 400-800 range depending on the shop and the quality of the parts.

I seriously doubt the throwout bearing is failing or noisy. What are the symptoms that make you thing it is?

In neutral or in gear a whirring noise is heard when the clutch pedal is depressed past a certain point. It is not always present but cold weather and a long highway drive brings it on. When the truck warms up the noise goes away. I first noticed it after a 300 mile drive on a turnpike but went away until next long highway drive. No problem all summer but now that it is turning colder it makes the noise until about 5 miles down the road then disappears. No problem with vibration, don't feel anything on pedal as clutch engages disengages.

Thanks for your >

Sounds like a throwout bearing to me.

Dry pilot bushing.

Nope, it's a dry pilot bushing. Still have to pull the tranny but if they just "replaced the TB" or the clutch, the noise would still be there. I've seen maybe 2 bad throwout bearings on nissans in 25 years of working on them but seen hundreds of bad/dry pilot bushings.

Why bother? If the throw out bearing is going you'll have to replace the whole thing at some point (clutch disc, pressure plate, bearing), so why not run it until it breaks? I've driven 50k on a squealing throw out bearing with no ill effects.

Because it isn't a "squealing throwout bearing" it's the pilot bushing and it's eating up the transmision mainshaft. If and when you do go in to replace it, you'll have to replace the transmission input shaft as well as the clutch to fix it.

Aaah, a whole different beast. Makes sense to fix it ASAP then.