I was driving my 2024 Raptor in the Pacific Northwest in 2H because the roads were dry, but as I got closer to the mountains, the rain hit hard.
Is it safe to switch to 4A at highway speeds, say 70 mph or even more? And is there a max speed limit for 4A?
Would appreciate some advice, thanks!
You’re good to go. 4A works like AWD, so you can switch to it from 2H at any speed without issues. 
I had a similar experience heading up a mountain near Steamboat Springs. Started losing traction in 2H, so I switched to 4A on the go. It handled way better. Even managed to tow a Buick SUV up an icy hill that couldn’t make it. To be fair, my Baja Boss AT tires probably helped a lot too!
You can run 4A whenever you need it; it won’t mess with your truck.
If it wasn’t safe, your truck wouldn’t let you do it.
Chance said:
If it wasn’t safe, your truck wouldn’t let you do it.
Try hitting 4L at 70 mph and see what happens! 
Chance said:
If it wasn’t safe, your truck wouldn’t let you do it.
Try hitting 4L at 70 mph and see what happens!
I’m definitely not testing that! But yeah, you have to be in neutral before switching to 4L.
Chance said:
If it wasn’t safe, your truck wouldn’t let you do it.
Try hitting 4L at 70 mph and see what happens!
We’re talking about 4A here, not 4L. 4L would be a disaster at high speed!
2WD should be fine for just rain.
Neve said:
2WD should be fine for just rain.
Haha, I gave you an upvote. Some folks think you need 4WD for every little bit of rain.
Neve said:
2WD should be fine for just rain.
I’ve noticed my back end sliding a bit in 2H when I turn in heavy Seattle rain.
Neve said:
2WD should be fine for just rain.
I’ve noticed my back end sliding a bit in 2H when I turn in heavy Seattle rain.
Picked up my '24 in April, and it rained the next day. Was merging uphill behind a slow car, floored it, and next thing I know, I’m looking at my own tailgate 
. That rear end gets loose fast! For long family drives in rain, I just keep it in 4A to be safe.
Neve said:
2WD should be fine for just rain.
I’ve noticed my back end sliding a bit in 2H when I turn in heavy Seattle rain.
Hey, that’s half the fun!
Neve said:
2WD should be fine for just rain.
I’ve noticed my back end sliding a bit in 2H when I turn in heavy Seattle rain.
Probably the tires and all that torque. 4A’s a solid choice in the rain.
Neve said:
2WD should be fine for just rain.
I’ve noticed my back end sliding a bit in 2H when I turn in heavy Seattle rain.
That’s likely the tires. Honestly, you don’t need 4A just for rain, especially Seattle’s lighter rain. Ease up on the throttle and take curves easy. She’s a big truck, not a sports car!
If you put it in slippery mode, it’ll automatically switch to 4H.
Does using 4A affect your MPG?
If you’re not sure, check the manual. Not trying to be rude, but it’s the safest way to get the right info and avoid any damage.