Bunny,

Most of the trouble I had in replacing my first 740 window involved removing the door panel without tearing chucks of it away because I missed some fasteners.

Remove the speaker grill ... on early 740s and perhaps on later models you'll see four screws or rivets that hold the speaker in the door. On my 87 there is a fifth screw above one upper speaker screw. This holds the panel in place and must be removed. If your 91 has a screw in this position take it out.

On early 740s there was a clip that hides behind the red plastic door light lense that also must be removed. On my 95 940 and I suspect on your 91 740 the lense also serves as the clip ... but it needs to be carefully pried out to release that section of the panel.

The plastic door release frame needs to come out ... a small plastic disc with a slot needs to come out to release it. 90 degree turn on the disc and it will come free and the frame will come out by pulling it back and up.

There are three white plastic clips at the very bottom, underside of the door panel that need to be pried out with a flat blade screw driver.

The door lock plastic end stem needs to be removed and the panel should snap out of the lower snap retainers by lifting it from the bottom and swinging it out ... you can then lift it off the top retaining flange. Do unplug the speaker wires and door light before removing the panel.

The glass it's self is pretty easy to remove and install. I pull back the rain sheild to expose the door innards ... run the windown down until I can get at the two clips that hold the glass to the regulator. Remove the clips ... angle the old glass out ... slid the new in ... clip it to the regulator and button everything back up. I do use a synthetic grease on the areas that require and already had lube on them. Make sure the glass is running true in the channels before closing things up. Hope this helps. Good luck.