Genie Garage door catches when opened

[mcii]

I have a Genie Series SD8000 screw drive garage door opener. Lately, when I engage the door to open, the door will open normally, but when the carriage gets to the where the drive screw is connected by the Collar (Genie name from the manual) the carriage sticks on the collar and makes a thunking noise, but continues to close all the way. It does not do this when closing the door. I have greased the screw drive (with both regular and lithium type grease) with no effect. I am afraid that this 'problem' will continue to get bigger; is there anything else I can do? Thanks,

[TJR]

You carriager probably worn out and when it come to where the screw drive is joint together with the colar and clip it slip a little.
Also make sure your door are balance correct.

[mcii]

You carriager probably worn out and when it come to where the screw drive is joint together with the colar and clip it slip a little.
Also make sure your door are balance correct.

I ordered a new carriager on Ebay for $15, and installed it this weekend. Problem solved! Thanks for your help.