Transmission stops working when hot

HOW many miles on the engine (REDUX)?/? 3.5L V6 engine? or 2.5 or the Diesel??????????
I'd have to drive IT to know.
let me guess the mech tested the car and it ran OKAY, so says" I can't find the problem. " ( what else")
you never told what the engine does , when it does fail and is Intermittent.
just that engine is ON. (runs)
and car does not move, sometimes.
what matters first, only when it fails, is does ENGINE RPM RISE fast and high when it fails.
see how that works, if it did the transmission is slipping (CVT are not fun here)
2500 RPM when it fails, right foot in to the throttle pedal this is transmission slip (failure)
if RPM are low failed, that is engine failure. (lean burning) or EGR stuck on or other problems , many.

lost engine power. has lots of causes; but this is gas(petrol) answer.

1: engine failing ,top cause , VVT or that chain loud noise? ?
2: spark plugs bad over 100k miles, (not diesel)
3: fueling bad, even bad fuel, or goes lean due to fuel pressure loss.(low) fuel pump weak?


driveLine choices day1, new not told gen 2, 2007 car.

Gasoline:
2.5 L QR25DE I4
3.5 L VQ35DE V6 <<<, seen in USA is it?
Diesel:
2.5 L YD25DDTi I4 no 2010 first

TransmissionCVT (Gasoline)

6-speed automatic (Diesel) 2010 up/

try new spark plugs and spark cop boots? 100k service point is is. and gaps will be way off ,when old

boots are here.

checkout NGK here. on COP boots x6

https://www.rockauto.com/en/catalog/nissan,2007,murano,3.5l+v6,1434436,ignition,spark+plug+/+ignition+coil+boot,10150

Check fluid level. In park. With engine running. If fluid level is ok it maybe internal trans.

SOUND LIKE TRANSMISSION GETTING HOT CHECK TRANSMISSION FLUID LEVEL.IF LEVEL OKAY FLUID + FILTER BEEN CHANGED MAKE SURE TRANSMISSION COOLING LINES TO RADIATOR NOT PLUGGED CAUSING TRANSMISSION OVER HEAT. OR LEAKING TRANSMISSION FLUID.

SOUND LIKE TRANSMISSION LOW ON TRANSMISSION FLUID.CHECK TRANSMISSION FLUID IF LOW ADD.IF FLUID LEVEL OKAY BUT LOOK DARK BROWN OR SMELL BURNT.CHANGE TRANSMISSION FLUID AND FILTER.

You have overdrive cancel soleniod problem. What it does, when you hit the overdrive buttom it activate the overdrive off and on. You should have it check.

Did you check the transmission fluid again. You could have a major leak. Or reving the car up so high it started to burn the clutches in your transmission, resulting in replacing the transmission. Always check the fluid. A few dollars for fluid is better than 1500 bucks for a new tranny

Bad News, your hydraulic pump on your transmission is wearing out. The only solution is a overhaul. I have a Subaru in the same condition, if you can live with it, do it. Just in case check the transmission fluid level.

First thing is check your transmission fluid level. 2nd thing is, if you haven't changed filter & fluid in transmission in a while, spend the money & do it, or have it done.

with it sitting for a year the filter is probably restricting the fluid flow

you can pour transmission fluid in the same place you check the transmission fluid..