Guys,
I'm starting to feel some vibration in the truck in my legal street runs. My best times are realized by 4WD, brake pressure till about 5psi boost and releasing. Starting to feel the vibration from the front end....

My questions are for those that choose to abuse thier trucks in 4WD do you remain in 4WD the whole run to 100mph. I don't know that you can push button back to 2wd after the launch? Afraid to try. Do you have vibrations?

 

When I play around with mine in 4wd, i will go back into 2wd at 55 or 60 mph. Speakin of vibration I have the same. Just decided to leave the stop light in 4wd and about 55 and up its got a vibration. Havent really looked into it . 4hi will be ok but dont try 4 lo.

 

At high HP levels I just have to leave it in 4wd the whole time. It wont come out of 4wd even if I wanted it to. LOL

I felt a lil vibration when launching hard under boost but it was due to my tires trying to spin. I lowered the front end for races and it cured everything. It launches straight as an arrow and feels smooth.

 

I launch in 4hi and hit the 2hi button after the 1-2 shift. It takes a second, but comes out every time.

 

what if you put it in auto 4-hi? I don't know if you guys have autotrac or not, I do, but I haven't tried it yet?

 

After I did my cam I tried doing that and it would shudder realy bad like something was about to break. Before the cam that's who I would launch bu tonce I had the extra power and the harder hit from the stall it just didn't like to be launched in Auto 4wd.

I used to launch in 4Hi then switch to 2wd but after the turbo I couldn't even do that anymore.

 

I'm with FL8 Z71 on this. I was driving around right after the radix install in the rain and decided to try out the auto 4wd. I pulled away from stop light under moderate power and the rear end broke loose, the 4wd kicked in and it was a horrible transition. Kind of like revving the engine up to 4 grand and dropping into drive from neutral except applying the power to the front diff. I will not use auto again.

 

I finally tried to shift on the fly under hard pull via the 2hi. It works. Didn't like the feel of it but I did it before the 1-2 shift and it transferred out at the shift. I'll try after the shift because I sure didn't like that shudder slip...

 

same experience here. i broke transfer case output shaft seals using auto4wd. i am more comfortable launching in 4hi. i usually switch back to 2wd after the 1-2 shift