How do i separate the old glass from the convertible top on a 2010 mustang

This is a common problem. At the factory, the top material is bonded to the glass. That bond is breaking down. You can use Gorilla taps or urethane adhesive, but you will eventually need a new window unit.
The window unit is separate from the actual top. The top must be partially removed to replace the window unit.

Karl at aoksales.com

the top will go down without glass breakage if retracted evenly

I'm not sure what you mean by pushed in. The top has rigid bows that support. the top. However i just replaced my top on a 96 mustang the top and rear window cost me under $300.00 (plastic rear window), I installed it myself with my brothers help and although it took about 12 hours to remove the old one and completely install the new one. An aphoulstry shop wanted $1600 to replace with heated glass. However the top I purchased had a heated glass option for an Additional $200. My Bows were still good and did not need to be replaced however it sounds like you may have bent the bow. in which case you would have to partly remove the cover to get to the bow you need to straighten if possible, or replace the bow the company i bought my top from www.convertibletopguys.com made by M&T Manufacturing. I believe they may carry replacement bows and tack strips as well. good luck

there is actually a tsb on this and the dealership should handle this concern

If I understand you correctly, your material is delaminating from the glass. One can sometimes fix it with urethane adhesive like that used to install windshields. If that does not work, you need a new window unit. Your window unit is NOT part of the top and can be replaced separately.
Water entering the car at that point should be channelled to a drain near the wheel wells. If the water is not leaving the car via the drains, one or more drain is plugged. Cleaning them out should help.

If the material is loose from the glass, you have a very common problem. Somtimes it can be repaired with urethane adhesive like is used to install windshields.
If that does not work, you must replace the window unit wich is SEPARATE from the top.
Get instructions here http://www.topgunwon.com/DVD/

i would take this to a window and glass place. this way you get a warranty

This problem is very common and is known as delamination.
If the problem is not too far advanced, you can repair it with Urethane adhesive. It is used by glass shops to install windshields.
Your top and window unit are two separate parts.
If the problem is beyond repair, you will need to remove the rear half of the top and replace the window unit.

Karl at topgunwon.com

The rear window for that top is a seperate curtain.
Replacement is best left to a professional.
You should cantact an automotive trim shop (upholstery) for them to quote it.

The way it is replaced, you have to take the top loose, roll it forward, replace the window curtain, reinstall the top. Depending on the condition if the top, it may need replacement also. That is best determined by the shop that does the work.
This is not recommend as a DIY project. I worked in a trim shop for years, and they are not easy.

This is a professional job for a conv. top shop. has to be sewn in at the bottom.

Removal
NOTE: Mark vinyl to be removed so it can be returned to the same position after disassembly.

1. Remove sail area panels as outlined.

1. Remove staples retaining elastic straps at each side of back window glass (42006) to rear tacking strip and folding top rear number 4 bow (51278) and remove elastic straps.

1. Remove staples retaining rear bow corner pad (537A71) and bottom of folding top back window curtain (52500) to rear tacking strips.

1. Remove staples retaining top of folding top back window curtain to folding top rear number 4 bow and remove back window glass .

1994 mustang. don't have 89 Window, Rear Installation
NOTE: Transfer markings from the removed assembly.

1. Mark with grease pencil center point on folding top rear number 4 bow in line with hole on rear of folding top rear number 4 bow .