Infiniti Repair Questions? Ask a Mechanic for Answers ASAP
The most common failure on these transmissions is usually valve body related. If it made a pop like something broke then I would be skeptical that something more than a valve body might have failed.
I would pull the transmission pan and look for metal, bad solenoids, signs of fluid contamination (sometimes the transmission cooler and radiator leak into one another).
Also, it's a 4wd vehicle right? I'm wondering if something in the rear axle snapped and it is now running on the front axle only. It's a long shot, but the pop noise is throwing me off a little. They usually just start slipping when the transmission fails.
Clunking isn't a normal transmission failure either. My bet is that something in the drive-line, either the transfer case or drive shafts is the real problem. It's really hard to say without looking at it.
There are very few "common" failures with these transmissions.
Has anyone scanned for trouble codes yet?
Sounds good. I'll be happy to offer any additional insights that I can.
Let me know if you need any additional help with this.
If it runs ok until it warms up I would suspect a problem with the valve body. It is probably somehow pulling away from the sealing surface and creating a pressure loss- maybe an easy fix once you get in there.