Nissan Repair: transmission, nissan xterra, nissan vehicles

Question
sorry for the confusion if there was any...

this is an automatic.

aside from cottman's who do you reccomend?  i'm in bellingham washington
-------------------------------------------
The text above is a follow-up to ...

-----Question-----
my 2000 nissan xterra (auto/4wd) has developed a tranny problem (i think).  it started everytime i put it in 4wd and now is doing it more often, especially if i have to put it in reverse.  i will be driving along after putting it in reverse (no 4wd usage) and it makes a big chunking sound, whirrs, and downshifts.  i have to let off the gas for it to chunk back into gear.  i just had the transmission flushed this summer and it's getting worse.
-----Answer-----
Tami,

Sounds like the valve body is plugging up and sticking.  I would take it to Cottman transmission or your local shop you trust and have it checked.  You said you changed the fluid so I think the valve body is failing.  It could be as simple as a solenoid replacement or there might be clutch damage requring a rebuild.  This is depending on how long it has been doing the clunking noise that requires you to let off the gas.

Answer
Tami,

You have a automatic with the transfer case attached.  You could have an adjustment problem with the transfer case so take it in for an inspection.  If there is not a Cottman in your area you could look up a speciality shop for Nissan vehicles or a 4X4 shop.  I live in Las Vegas so I do not know a good shop in your area.