Well got the replacement tranny back in today and everything is working fine. Until I come up to a stop sign and put the brakes on hard. Truck just falls dead and wont start back up. Wont do anything and the dash and running lights wont turn off. Get it back home and disconnect the battery and tried to start it again and it would crank over and shut itself right down and gave me SERVICE BRAKE SYSTEM. So I put it in N and start it and it fires up. Do a burnout and the SERVICE BRAKE SYSTEM goes off. drive it down the driveway and hit the brakes hard again and same thing. Falls dead and nothing. Anyone got any Ideas?

 

Maybe something is lose and cutting off power you should double check everything.

 

check all your grounds and be sure no wires were pinched when the tranny was installed

 

all wires are good. nothing pinched between the bellhousing. it only does it when the brakes are applied hard and then its like it locks itself down in security mode or something. I have noticed that on the dash it shows no lines under the gear indicator that I am in after this happens until I reset the ecm.

 

Could it be something with the Neutral Safety switch/circuit?

 

My truck did the same thing but the starter would also engage while driving, I traced it back to the park, neutral switch, changed it and the problem was gone.

 

switch connection is fine. it only does it when I stomp on the brakes. then a service brakes soon light comes on along with my abs light.

 

ok update. its giving code u0107 and it says it "lost comunication with throttle body". called the dealer and they say that 90% of the time its a ground shorting at the battery but my cables are tight. anyone else experienced this?