2H to 4H on the fly

[mrpanic7]

I just tried this at about 40 mph on a completely snow covered freeway and no go. It wouldn't engage and all the 4wd lights started flashing...pulled off at the next exit and turned the truck off...then back on and shifted going slow and all was well. So, for me i'm going to stick to really low speeds. However mine is an 03 with like 135k on the clock so i'm a bit older than most...

mine's an 04 with 137,000 miles and changing on the fly works perfect

 

[scottm]

Sometimes the teeth aren't aligned to smoothly engage right away, then one wheel has to turn slightly more than the others for the gears/splines to match and slide into position. So going straight you might have a little hesitation until you turn a little. If the gears have a load on them they might not slide easily, you might need to let off the gas slightly for quickest engagement.

 

[settytb]

Tried neutral and slightly turning left to right in my lane and still no go. It scared me. It's the first time it didn't engage when i wanted it to. I've done it at around 25-30 a few times before. Not sure why it didn't do it that evening but it's worked since then... Who knows.

 

[Iron Clad Lou]

the 4th gen 4WD system on the V6s is far and away the best system I have ever had the pleasure of using!

 

[TechWrench]

I just tried this at about 40 mph on a completely snow covered freeway and no go. It wouldn't engage and all the 4wd lights started flashing...pulled off at the next exit and turned the truck off...then back on and shifted going slow and all was well. So, for me i'm going to stick to really low speeds. However mine is an 03 with like 135k on the clock so i'm a bit older than most...

I have had my '03 since new, and have never had a real problem switching while in motion. But, I have noted a few things to keep in mind. Don't make the switch while turning. Don't make the switch while under load (accelerating), and when it is real cold out, it seems to take longer. I have found that if I engage switch while driving, it seems to work better if you ease off on the throttle and let it coast a bit. Also, if you switch while standing still, it helps to switch from reverse to neutral or drive to neutral. And if you are going to 4low, you should be stopped, and in neutral. And the same goes for the diff lock function.

Finally, don't expect the change to be immediate. Mine usually switches within 3-4 seconds, but it has taken as long as 10-15 seconds on some occasions.