Is it safe to launch in 4wd, then press it to 2 hi once i take off?

 

Good for traction, bad for the drivetrain. I really never had an issue with my trans, gears, or transfer case. I launched quite a few times spraying a 100 shot out of the hole. Even with a converter, it never felt unstable. When I wan't racing, I took it easy on it. Parish8 made the statement that some nights he would make 15 hard launches on his truck. He did have a few drivetrain issues because of it. Not that its bad, you just have to pay if you want to play.

 

would it be ok to launch in haul/tow mode??? i've heard of people doing this to get better 60' times.

 

I actually ran my best time in 2WD. I think it varies on how you launch though.
I am still a bit used to launching with a supercharged FWD

 

It would be ok to do tow/haul mode, but you will run slower times because of the lowered shift points and you probably get more shift retard too.

 

i launched MANY times in 4hi, once i started really hiting it hard out of the hole i figured out it was smoother to launch in 4hi than auto4wd. auto4wd gave it a chance to get spining and then had to try and get some grip back.

when i got over 100mph in the 1/4 i started to feel quite abit of driveline vibration in 4hi so one day a tryed pushing the 2wd button at about 60mph while at WOT and belive it or not it sliped right out of 4wd. that was with a 6.0+8psi+75shot and it came right out. after that one scary test i did it every time and was thinking about hooking some kind of time delay switch up to the button, something like after 3sec give it the 2wd signal. all the vibration went away when i did this so it was really coming out of 4wd.

one thing i tried to do was as soon as i got off the track i shifted it back into 4wd to give it a little time to get fully engauged, i didn't want to try and hit 4wd at the line and have it get 1/2 way engauged and break something because of that. there were a couple of times i forgot to put it in 4wd and had something like 2.6 60'times. it was like being on ice.

 

I launch my Dmax in tow/haul with 4 hi engaged.I button out into 2-hi at about 60mph.If I button any sooner the tires spin really bad.I have no worries about hurting the Allison or rearend.The half-shafts up front make me nervous though.

 

422SS, what all do you have done to your D-max? Ive got one too, the sucker flys! They are fun!

 

I've only done Edge Hot Juice and amsoil air filter.My best pass was made on a less than ideal day weather and track prep wise.I'm waiting to improve on times when it get's cool in the fall.