Most likely needs toe out.  If you measure lug to lug on the front/back of the front two tires, the front of the tire measurment should be like 1/16 or so More than the rear.  Make sense?

i set my toe in 1/8". i didnt think it should be set out. i guess ill try that in the morning.

What is your castor set at?

What did you set the pre-load at on the trunion bearings (knuckle bearings) at?

How long are the front shackles from bolt hole to bolt hole?

How much drop on the front hanger?

What size tires, height and width?

Are your u-bolts tight?

Are the spring bolts tight?

Are the spring center pins tight?

There are a lot of things that can cause "death wobble".

i didnt have a pull scale to set pre load. i just reused the same size shims that were there

im running 37x12.50r15 MTRs

i will recheck all bolts. i didnt think about the spring center pin.

i know a lot of things cause death wobble. but does it usually happen at only 15 mph. I'll add more info after i check everything tomorrow.
thanks for the replies