vibrations and clunk when i let off trottle and hit trottle
 

np203 transfer case with doug nash dne2 kit found the sticker on the sun visor i seen an other post like this one same problem but 205 but no solution is it a mount problem or transfer case. u joints r new some days after mudding drives smooth as could be no lift kit front wheel bearings r good maybe a motor mount

Re: vibrations and clunk when i let off trottle and hit trottle
 

Could be seveeral things, motor/transmission mounts or just loose, or u joints.
You can check the mount by applying the brakes and have some put it in gear, if it moves excessively it's your monts. U-joint get under the truck w/ motor off and see if their is play in the drive shafts.

Re: vibrations and clunk when i let off trottle and hit trottle
 

u joint time ........exactly the sounds and symptoms i had

Re: vibrations and clunk when i let off trottle and hit trottle
 

u joints or pinion angle?

Re: vibrations and clunk when i let off trottle and hit trottle
 

u joints r not bad i check them all the time.. pinon angle is stock and it stopped doing it after i ran the truck with it in the 4 lock postion for about 5miles with hubs unlocked it has the dne2 conversion kits still has the sticker on the sunvisor

Re: vibrations and clunk when i let off trottle and hit trottle
 

You didn't say what kind of truck you have, or if you know about the Doug Nash unit. So please excuse me if I sound like a know-it-all. I'm not, believe me. The dne2 is an overdrive that installs behind the tranny- in place of the tail stock on the tranny and hooks up to the drive shaft. It's electrically controlled by a toggle switch in the cab of the truck. The switch engages or disengages the overdrive thru a solenoid that slides a fork for engaging.
Anyway- could the overdrive be partially engaged?

Re: vibrations and clunk when i let off trottle and hit trottle
 

1978 k5 blazer with th350 tranny , np 203 transfer case, 12bolt rear end with a 2 peace drive shaft, dana 44 in front and 400sbc and it says dne2 part time conversion kit from doug nash bla bla bla drive truck with 4lock on once a week for 10miles drive once a week with hubs locked for a few miles to keep inactive parts lubricated somthing like that

Re: vibrations and clunk when i let off trottle and hit trottle
 

Could be a bad pinion bearing. Could also be an out of balance driveshaft

Re: vibrations and clunk when i let off trottle and hit trottle
 

possible its a 2 piece drive shaft and it acts like the splines are worn out when u twist it... it has no clunk when u put it in gear when u just started it and everything is cold its about 42 out side and im pretty sure 203 transfer cases take sae 30 motor oil because the book say it dose and i checked it and it looks like tranny fluid so maybe oil to thin causing clunk but vibrations idk yet