4x4 Vibration Help

[Forced Induction]

Guys, I need some help. I recently raced the old DMAX at the track with the new found juice on level 4, but it seems as if the driveline got damaged somehow. The truck has nothing done except juice and K&N. The launch was in 4wd, t/h, and power braked, but a little too much which is where the problem comes in. The rpms were around 2400-2500 or so with the brake pedal on the floor, literally. Then there seemed to be a metallic grinding sound, after the launch, it didn't seem right, so I aborted the run before half track. The next run was also 4wd but with a more controlled launch, no problem.
However, now when driving around town in 4wd, under acceleration the truck appears to have a vibration, and a resonating vibration or hum at 55mph, very annoying. 2wd seems to be fine, for the most part. 4wd is only used in the rain for acceleration purposes and for quick sprints against mustangs and the like. Please give me some ideas where to start looking for the problem and some possible troubleshooting ideas. I currently have the juice on level 1, just to avoid the vibration. It is still there but not as noticible. I'm going to perform some more tests with the juice on 1 and in 4wd to see if anything changed without the added power. Any help would be appreciated, thanks again.

[thechevyhdman]

I think a slight extra noise vibration etc etc, is normal for 4WD to a certain extent esp. on wet but not slick roads etc. Can you feel it through the steering wheel, does it feel like its coming from front end or transfer case, See if its even more pronounced in 4Lo. Check the simple stuff first. But every 4WD truck Ive driven starting with the ol 82 has always felt less smooth/more vibrationanny, even since new while in 4bad

[Lawnboy]

Well this topic has come up many times in the past, but, as I've stated before, I have to agree 100% with Thechevyhdman. Never have I been in a vehicle that I couldn't feel/hear the front drivetrain in "action". I wouldn't even attempt to travel at more than 45mph in 4x4 let alone highway speed. 4x4 is engineered for SLICK surfaces (rain, sand, snow, mud, etc) NOT LAUNCHING on the dragstrip. The slight difference in tire diameter due to the front end weighing more than the rear would cause gear bind in a short distance. Make sure that your tire pressure is adjusted to allow for this (ie: pump up the fronts and air down the rears).

As for the metallic grinding sound at launch....Maybe you weren't fully engaged? Were you bound up at the line from turning off the staging lanes? Either way, it doesn't sound good. Did your "vibration" start AFTER this launch, or was it always present?

Man o man, I'd be afraid of breaking SOMETHING launching in 4x4 in my old truck let alone a more powerfull one!

[SoMnDMAX]

See-

http://forum.62-65-dieselpage.com/cgi-bin/ultimatebb.cgi?ubb=get_topic&f=7&t=002036&p=


Since the above post, my vibration has dissappeared.

Lawnboy- The 4x4 launches won't hurt your old truck. My K3500 SRW 454(tweaked)/400(also tweaked) took one heck of a beating from me, and it's still on the road!! :D :D

[Forced Induction]

Thanks for input. I am somewhat at ease now. It just seems like it wasn't there before but who knows, maybe I'm just paranoid about the Juice and breaking things. I'll just keep on ridin it and see what happens. Thanks again guys for your help.

J.A.