Talking about the rubber flaps that slide in a slot inside the door window opening to seal and wipe your side windows and prevent rattling.

I've replaced these on a couple of AD trucks, always with extreme difficulty - or in the case of my current panel truck I wasn't able to get them in at all. I thought, no way were factory assemblymen going through this much hassle to install these! Now I find that many vendors are selling generic extruded rubber seals that bear no resemblance to originals. What many are selling has a T-shaped base. When I chiseled my old rubbers out, they had a Y-shaped base.

I did some research and found that Classic Parts sells the original-style y-shaped seal. And at $5.95 it's not like they're expensive. I bought some and they slip right in effortlessly. If you're replacing your window sweeps do yourself a favor and get this type.

Below is a photo profile of the original style, Classic Industries style, and the generic style that most places sell. Notice how huge the t-style base is; no way will it fit in the door slot without extreme measures!

Very good to know. It would be very frustrating when you’re working basically blind, by feel, and things won’t fit. I suppose I got lucky when I ordered mine. They slid right in as well. Mind you, I think I got mine from Classic too. 😎