A few 4000q/Quantum Syncro Q's

[CTDiesel at aol.com]

If i could get some good feedback on a couple questions for a Quantum Syncro
similar to 4000q.

1.  I had the timing belt replaced by a mechanic (lazy me, I already had the
engine open for new lifters I put in) and he asked if i wanted the tensioner
roller replaced also.  I said yes since I didnt know when it was last done.
I know the water pump is the belt tensioner right?  And new water pumps from
thepartsbin.com come with the toothed roller so isnt that tensioner roller?
He didn't replace the water pump so I have not a clue what tensioner he
replaced since i cannot locate it at any part of the belt. Unless he pulled
off the toothed part and put a roller in that.  That leads me to the current
question.  I have a rattle that sounds like pebbles in a tin can at all RPMs.
 I listened with a screwdriver and believe its the water pump.  Everyone
agree?  FYI 145,000 miles on car.  So would it not have made sense for the
mechanic to replace the water pump instead of just the tensioner roller?

2.  How difficult is it to open up the rear differential for replacing
bearings?  There is a growl when pulling and decelerating.  Has anyone run
into snags?  I dont think its too bad.  I have leaking seals and go through
gear lube every 500 miles.

3. Does anyone know where to get a wiper assembly.  My left side wiper spline
has stripped out completly. I was thinking of just JB Welding the wiper on
the spline.

Thanks in advance,
DJ