I have a 1990 chevy blazer 4x4 i put a 4" lift on new springs, shocks, and bolts all around and i droped the caes with stock spacers. the angle is good front and rear also the rear is angled . but i get a vibration all though the truck cans anybody help?  

could be a number of things, did you put bigger tires on it? they might not be balanced right. Could be a bent driveshaft or even an unbalanced driveshaft.. bad U joint...

For more help.. try... www.67-72chevytrucks.com (they have a 73-91 blazer message board as well as a 4x4 board.. )

how noby are your tires  

Did you correct pinion angles? Pinion angles change rapidly on short wheelbase vehicles when you lift them, even if it is only 4".  

He said he lowered the t-case, which should have brought it back into the realm of ok. Sounds like a bad balanced tire or some serious ball joint wear!? Could be lots of things, can you give some more details?  

I guess I misinterpreted "droped the caes".

Could still be an issue, depending on how much the t-case was dropped, ie too much or not enough. Rotating the case (aka clocking) usually has little effect on rear D/S angle, but improves the front angle.

Can you lower the t-case w/o changing the angle of the whole engine and trans, as this isnt a divorced setup?

well it has auto locking hubs and i drove it with out drive shaft. but new one is back on, there are new front and rear shafts. i droped the case about 1 1/4 to 1 1/2 inches made angle better for rear front looks good too.i have 35" kumho m/t tires on it but did it before i got new tires. all the angles look good not sure of the problem. and like i said rear is angled also so not sure. there are new ball jonits and tie rods in the front. if i can get your email will mail u pixs. thanks  

Honestly, 4"s and 35's shouldn't have pushed the angles out of range. You probably have some slop in your steering or ball joints are going bad.  

Is the rear diff perfectly straight with the driveshaft ? You may have angled too much. If you have a one piece driveshaft without a CV joint this could be the problem. The output of the t-case should be as close to parallel with the output of the rear diff. If you draw an imaginary staight line from your rear diff axle housing to the t-case output, you should have a parallel (or as close to parallel ) line. The lines should not intersect or separate from each other. If you go too far in either direction you shorten the life of the u-joints. This may be where you are getting the vibration from. One solution may be to look into a driveshaft with a CV joint, but you may still get vibration at high speeds if your pinion angle is whacked. - Just some ideas. I'm no expert on this by any means. Something I had to fix on my truck too.