150K out of an automatic is very good, especially if you didn't change
the fluid every couple years. As to the actual cause, it coud be many
things. Maybe the front pump, maybe something else. I assume you made
sure it's full? Probably time for a rebuild.

Your tranny sounds like it has taken the high road.. 150k stock on the
fondly nicknamed "auto-tragic" maxima is commendable... If you want to
go to the source.. Jatco transmission (japanese auto transmission
company) the creators of this notoriously weak transmission, opened a
rebuilding plant in tennessee since they figured they could make a
killing stateside vs exporting the rebuilt/new transmissions to the
dealerships... If not, research your rebuilders.. If you're in the
tri-state area, check out http://www.levelten.com to get an idea..

Follow up on my own post.

Car has been repaired.

Phoned arround several transmission shops in my area, DC metro. Most
quoted a price $1400 - $2650 depending on the required repair. Found a
local shop who listened to my description of the failure:

Transmission operates faultlessly for years. No symptoms of impending
failure. Out driving one day and pulling away from a Stop sign under
strong aceleration the drive quits completely with only a slight
thump. Car coasts to a halt. Motor revs but no drive in any gear.

Shop owner tells me this is most likely a torque converter failure.
Maxima torque converters regularly strip the female splines in the tc
where the input shaft enters.

Anyway his diagnosis over the phone proves correct.

Cost:
Torque converter $235.00
Labour    $500.00

Car runs faultlessly again. Hope this may help someone else in the
future.

Al Moodie.