2008 gmc 1500 speedo cuts out on slow down, abs kicks on, wont shift

vaperev2014 · July 29, 2015

hey there,

I am having an issue with my 2008 gmc 1500..

I used to work for GM but now i no longer wrench or have access to a tech 2

first things first the truck is a 2008 gmc 1500, extended cab, 5.3L 4x4

I put a 3.5 inch rough country lift in about 8 months ago, along with 20" fuel octane rims and mickey thompson 33x12.5x20 tires

I have been driving the truck lifted and all for the last 8 months without issue, but now every time i attempt to slow down and stop the speedo jumps around as soon as i hit about 40km/h as im slowing down, and then just drops to zero, and if i try to accelerate once the needle for the speedo has dropped the truck will not shift, and if i try to come to a complete stop the abs kicks on.

when this happens no lights come on, no abs or anything.

if i come to a complete stop and then start again, shifting will return to normal and all will be good until i attempt to stop again.

the truck has 180,000 miles on it, but has been extremely well maintained, i replaced the VSS on the transfer case as i know this is where the speedo gets it signal from, and this didnt change anything. truck maintenance is always kept up (synthetic fluids all around)

any ideas?????