1998 Mercury Mountaineer AWD. The vehicle pulled up to the store just fine but when leaving we tried to start the car we only got a click click click. Tried having someone jumper us thinking the battery was bad and same result. Bought and installed a new starter the next morning int he parking lot on the 4th of July 11' and same click click click. Had Autozone check the old starter and tested just fine... battery was bad so did replace that also along with a starter relay. Still click click clicking..... Had it towed this morning to a Meineke and they would have guessed everything i changed... they asked if they could try a new starter and about an hour later told me that they believe it to be that the torque converter was not disengaging from the flywheel and that they couldn"t turn the flywheel in neutral.... they want to go into the tranny and change the torque convertor because the starter cant turn over the tranny and engine. Getting 800 cranking amps off the new battery.....

Thoughts...

 

I would not let them mess with the tranny or torque convertor let a tranny place look at it first to let you know for sure you could have got a bad starter I had something like that happen to me it end up being the battery cable to the starter .
hope you get it going

 

How does a TC disengage from the flywheel in neutral? It is bolted to it. Either your tranny is seized (rare but not unheard of) or your motor is locked up. I once swapped engines on a GM only to find that the Compressor was locking up the motor. Why don't you try removing the belt and seeing if you can turn the motor with a socket or the starter.

 

"Clicking" is a broad term as the sound can come from various tihngs and possibly be confused with ticking or clacking.

The source of the clicking sound needs to be identified. What part is clicking?

The starter solenoid generally makes a fast repetetive 'click' sound when low battery or insufficient voltage to operate the starter, or if perhaps the starter cannot turn due to a frozen engine.

Did you or Meineke inspect the ring gear teeth? You identified that the starter is working with test at A-zone, but is it also kicking out and engaging the ring gear on the flexplate when installed? If a few of the ring gear teeth are stripped, this can cause a louder "clacking sound" as the starter drive gear kicks out to engage and turns on the broken teeth, but does not spin the engine. The engine should still be able to be rotated by hand in this case.

If confirming ring gear, starter, solenoid, and connections are good... and engine will still not rotate in Park or Neutral, then the engine and trans has to be considered to identify which one is the problem.

Will the car roll in Neutral? Will the driveline spin when rolling the tires?
If so, I would predict that it's likely be engine related.

Did you remove the spark plugs, for the off-chance that a cylinder may be flooded from a bad (leaking) injector causing hydraulic lock? This would eventually settle into the oil pan and show the oil being diluted and the engine eventually being able to turn. Removing them would ease turning engine by hand anyway to 'feel' for grinding of any bad internal parts that may cause lockup.

To isolate the engine/trans, the engine still needs to be rotated to access each TC-to-flexplate bolt (typ. 3 or 4). Since this apparently cannot be done, then (typ.) VERY carefully slide the trans straight back and inch or so from the engine but not completely off the TC (if possible) to access the TC-to-flexplate bolts to separate them.
Or you may need to remove both eng/trans together as a unit and separate supported level on floor if unable to reach all the TC bolts in-car.
Once separated, you can see if either eng or trans rotates as normal.

My son has a '99 Mountaineer (for sale) and luckily I haven't had to do any major work on it.