GMC 1996 Sierra Owner's Manual page 272

Manual Transmission Fluid
When to Check
A good time to have
it
checked is when the engine
oil is changed. However, the fluid in your manual
transmission doesn't require changing.
How to Check
Because this operation can be a little difficult, you
may choose to have this done at your GM dealership
Service Department.
If you do it yourself, be sure to follow all the
instructions here, or you could get
a
false reading.
NOTICE:
Too much or too little fluid can damage your
transmission. Too much can mean that some of
the fluid could come out and fall on hot engine
parts or exhaust system parts, starting a fire. Be
sure to get an accurate reading if you check your
transmission fluid.
I I
Check the fluid level only when your engine is off, the
vehicle is parked on a level place and the transmission
is cool enough for you to rest your fingers on the
transmission case.
Then, follow these steps:
1 . Remove the filler plug.
2. Check that the lubricant level is up to the bottom of
the filler plug hole.
3. If the fluid level
is good,
install the plug and be sure
it is fully
seated. If the fluid level is low, add more
fluid as described in the next steps.
6-22