New to slides

This^^^^.
Our trailer always leans a bit to the slide side after deploying it if I level the trailer first. I have found the best was to level it side to side but leave the slide slide one or two marks on the bubble level high. My bubble levels are mounted on the front of the trailer and one one the side. After a while you learn how much to leave the trailer off level before deploying the slide.

I also put down the stabilizer jacks on the slide side after leveling but before deploying it. Even if parked on concrete, the slide side will be a bit low because of springs and settling of the trailer. The reason I put the jacks out before deploying the slide is because the front jack is under the slide and it is very hard to crawl under it and operate the jack.

I only went through this routine if we were going to be parked for any length of time. Never put the jacks down for an overnight or even a couple of nights.
Hope this helps you out a bit. :)
Barney

Repeatedly operating the side(s) before the TT is leveled at the campsite can cause them to go out of alignment. When you arrive at your campsite, level the TT as best as you can first, set your stabilizers, and finally extend the slides. When leaving, retract the slides first, retract the stabilizes, and then hook the TT to your TV. The slides should operate just fine as long as the TT is within 1-2 inches of level.

I'd be more worried about the refrigerator, personally. If your camper is level enough to be comfortable, its level enough for the slide.

I just remembered a neighbor camped a few spaces down from us in Thunder Bay, Ontario. He came over and asked me to help him push his slide back in. His wife was inside pushing the button while the two of us lifted and pushed to get it back in. It was a lot harder than I expected.

After we fixed it, I asked a few questions:

"Did this just happen?"
"Do you always level up?" (I had noticed that his Class A wasn't very level at all.)

He said it happens all the time, and that he always has to find someone to help him push it back in.

When I asked him about leveling, he said "Level?" It never occurred to him.

I don't know if things went better for him at his next stop when (if?) he leveled up or if the damage was already done.

"Perfectly level" doesn't seem to exist, but you want to be as level as you can, especially front to back. You don't want the slides to be tweaked at all.

It also depends on the size of the slides and whether they're in a pair or not (where the left and right slide in and out together). If you're out of level from side to side, then the motor has to work harder to deploy the uphill slide and to retract the downhill slide.

We've run ours out without leveling up first when we couldn't help it. The smaller bedroom slide doesn't complain much, but the two large slides in the main living area audibly complain when they bind up.

Short answer: Level up.

No need to be perfect on leveling. Slides are not that temperamental.

The worse thing about a slide? Once you have one, your wife will never consider any other RV without one.

The size of the slide, and type of mechanism, can have an affect on operation. You say large slide, so I would recommend open/close when close to level. A few other tips for slide operation are keep rubber wipers slippery with baby powder, and leave door open, when running slide in/out. When setting up to camp, I level trailer, lower crank down jacks, before extending slide.

My electric awning also works best, when close to level.

Jerry

As long as you can walk in it and nt feel like you are walking uphill your fine.

With that said, invest in a good set of bubble levels and mount them inside the LF storage door. makes sure you use a carpenters level to get the trailer level first before you attach them. then you can always get the trailer clolse to perfect every time without going inside or around the trailer (other than to add leveling blocks if needed.