<Taylo...@Verizon.net> wrote:     97 Chevy S10 117k mi

I am the original owner.   I change oil every 3000 miles. It runs just
as it always has; no performance problems.

After I had the rear seals replaced I noticed a slight rattle from the
rear of the engine when the starter first kicked.    And I could hear
the rattle during acceleration (like a jar of marbles bouncing around
inside).   It has become louder but still happens starting the truck
& only when accelerating.        I had it checked at the dealer and
the mechanic said I need a new engine.     He listed the causes:

Rod Loose
Knob crank
Low end rattle rear engine

I will have another mechanic check it out.      Any thoughts?
_______________________________________________________

"Knob crank" could have meant "Knock crank".

    A worn crank bearing will knock when started and knock during
acceleration, but get quieter when there is no acceleration.
   A bad rod bearing will knock when there is no acceleration and
get quiet under acceleration.
   A knock sounds like a hammer rapidly thumping the engine block.

Some loose hardware rattles and jingles under vibration or torque,
such as exhaust system parts.   Rattles like marbles in a jar could
be a failing bearing in a water pump or some other belt-driven
accessory.  A rattle like a can of gravel could be a sticking fan belt.

Having another mechanic check it out is a good idea.    I think you
should also go back to the first mechanic and ask him to explain
what the thinks is the problem and why.

Good luck.

Rodan.

If it was my truck I'd be headed back to the guy who changed to seals
to find out what he did wrong..like leaving out an endplay shim or not
properly tightening the flywheel/flexplate.

Chris

has broken loose the casing. Very common problem on this year S10.

If the noise started after the rear seal was replaced I would say you
have a loose flex plate or converter bolt. Possibly even a cracked flex
plate.