I have a 2003 Pace Arrow 37a I assume your slide toppers ate the same as mine I replaced mine this spring. It was relatively easy just takes two people and a couple of screwdrivers. I purchased mine from tough top awnings and have been completely satisfied their web address is
WELCOME TO TOUGH TOP RV AWNINGS. There are several how toos on their web site. It took my son and I about 2 hours to replace both awnings. Tough Top has an orderform you fill out that is pretty self explanitory. When you order your awnings you will need to know the origional MFG of the awnings, length and depth.
Installation is pretty forward it takes two people.
1 Extend the slides.
2. Roll the awning out full length by hand and pin it in place there is a hole to do this in the awning roller assembly.
3. remove the screws from the track.
4. remove the old awning.
5. install the new awning.
6. reinstall the screws in the track.
7 remove your pin holding the awning full open.
8 adjust any anti furl devices on your awning.
All of this is explained on Tough Tops website.
Also you can check you tube for slideout awning replacement.
My awnings were A & E so my instructions were based on my type of awnings.
I hope this helps