While running at the speed of about 8 to 10 kph the running belt stops.

run the fault codes
at the speeds nominated it appears to be a servo/solenoid problem that will show in the fault reports
at 30 kph it could be the down shift or transmission actuator or vacuum hose to the unit problem
at 90 kph it could be an over drive / transmission actuator
if you did the yest at the local garage , take it to an accredited auto transmission specialist shop
I suggest that because any mechanic would not stop at the transmission but would satisfy the customer problem

Try below:

ERROR CODE
DESCRIPTION
E1
Speed error (The treadmill running speed is 3.2 kph faster than the displayed
speed). The treadmill will stop immediately when the console detects this error.
E2
Speed error (The treadmill running speed is 3.2 kph slower than the displayed
speed). The treadmill will stop 16 seconds later after the console detects this
error.
Troubleshooting / Resetting error codes
In the rare event of the treadmill displaying an error code ("E" followed by a number), simply reset
the computer by:
1. Step off the treadmill. Ensure that you are clear of the running belt.
2. Turn the treadmill off at the master power switch located near the motor housing.
WARNING: Ensure nothing is positioned near or under running belt which may possibly block
it's normal operation.
3. Turn the treadmill on at the master power switch.
4. Ensure that the Safety Tether Key is securely and properly installed onto the console or just
reinstalling the Safety Tether Key can also reset the display.
If the above does not clear the error code, please contact the nearest Dealer/Service Center

LifeGear 97320 Owner Manual Page 17

The side the belt is running to is the side you adjust first.
Turn the machine on to 2 kph.
Stand with 1 foot on the side rail
Try and stop the belt with the other.
If you can stop it tighten both sides 180 deg clockwise.
Repeat test until you can not stop the belt.
Now it is tight.
The rear roller has to be even to keep the belt from running to 1 side.
If you have turned 1 side more than the other the belt will run to the other side.
Hope this helps.

Check that you have not reached the engine rpm limiter and the CPU is going into limp home mode. Run fault codes as the engine light comes on it may tell you the problem

Did you try the instrument self test? With ignition switch in off, press the odometer reset button and while pressing it, switch ignition in run. Now all indicator lamps will come on and you can release the button. All indicators will run to full scale and should return to normal position.
The instrument cluster gets the speed information from the PCM (powertrain control module). The PCM gets the info from the ABS controller. I would pull the fuse from the ABS controller and see if it will change the speed indication. If it does, then the problem is with the ABS controller, if it doesn t, then most probably the instrument cluster is faulty.

You need to tension the belt .
Turn the machine on and up to 4 kph or 3 mph.
Stand on the side rail with 1 foot and try and stop the belt with the other. If you can stop at all tighten the rear roller with the allen key provide with the machine. Turn it on both sides clockwise 180 deg whilst machine is still running. If still loose tighten another 90 deg.

press and hold the stop button while placing the key on, then release and hit speed + or - I don't remember which right now. One turns the store demo on/off and the other is for mph/kph

Hi
not to sound funny but are you sure that you have this tread set in the units (mpg/kph) that you require. i have worked in loads of gyms and its a common problem that people think the belt is running to fast because its set in kph and that thinks its in miles eg 9mph = 14.5kph
you can check and change the units in the club setting menu.
hope this helps :)

You need to replace the walking belt.