Hi, Im sorry to hear that.
Yes if there is slack its time for a new walking pad. Its easy to replace and I will help you with that.
Just make sure its not the roller bearing making the noise first ;-)
I will help you replace the walking tread when you have the new one.
The best place to get that part is: Treadmill Doctor:
TOLL FREE 8am - 5pm Mon - Fri CST
They are fair priced and supply quality parts for treadmills;-)
I use them all the time for my repairs in the feild.
I will stick with you until this is complete.
Please rate my service kindly.
Also it is the only way I am credited for my time and expertise with you.
Once you rate, I will be notified and will add your question to my priority list so you can reach me anytime until this problem is solved.
Then you can reach me by simply replying to this message anytime.
Thank you and have a great day!