3.3 Xterra Vibration/Shudder

[hsckris]

Friend of mine has an Xterra with the 3.3, 4x4, Auto, about 150k on it. Its a 2000 or 2001 (I forget).

When he starts the truck, and while driving, it will shudder or vibrate, all of the sudden and seemingly randomly. It feels like it is coming from the engine, but its hard to tell. Looking under the hood, the engine doesn't appear to be vibrating too much.

It has a new air filter and fuel filter, new plugs, and fresh oil.

Any ideas?

[Big-Bird]

I had the exact same issue a few years back. It only made the noise when I put my Xterra in gear. The engine sounded like it had spun a bearing or blew a torque convertor in the transmission. Turned out to be my alternator which was starting to seize up and the bearings were spinning in their housings. YIKES!!

Have your friend take the belt of the alternator and start the truck. A few dash board warning lights WILL come on but as long as he doesn't go to far this won't be a problem. If the noise goes away then the alternator is toast! The bad news is alternators aren't cheap. I highly recommend the rebuilt Bosch Alternator. Happy troubleshooting

[hsckris]

Welp, thanks for the recommendation.

It wasn't the alternator... it was the timing belt b/c it ended up braking, so -- what can you do. I didn't know he hadn't changed it at 100k.

Again, thanks for the help.