28 or 31 spline rear end?

1988 F150 XLT LARIAT 2WD
Axle Code 18 - Ford 8.8 - 3.08 gears

From what I've read only the mustangs had a 28 spline and pretty much everything else had a 31. But I need to know which one mine is and if that's correct. Looking to get a locker for the rear, tired of the one tire fire.

My lights or stereo won't work?

So I have a Ford F-150 XLT & the headlights won't work work on it. Sometimes replacing the bulbs seem to be the only option but then after a few days they stop working. The stereo won't even turn on anymore.

Anything about the boss 508UAB radios?

I have an 87 Ford F-150 and my wife bought me this cd player. I got it all wired up but we realized that the lights stay on after I turn everything off and get out of my truck. Does anyone know why it does that and if there's a way to fix it?

2018 Ford F-150, 2018 Chevy Silverado 1500 or 2018 Ram 1500?

I'm looking to buy a new truck. Grew up in a Chevy family and have only owned a Chevy. Traded it in last year to buy something more fuel efficient since i was living in San Antonio. Now that i'm in a smaller town i wanna buy another but i'm undecided. I love Chevy but i wouldnt mind buying a F-150 or Ram if i know they are reliable enough to last me 6-7 years. Give me yalls thoughts and opinions.