I have a 2000' Silverado and I just pulled the 5.3 and put in a 6.0. I got it all put back together and the motor started and ran fine. The problem I am having is now it won't go into gear. I am using the old wire harness and computer from the last truck and it starts/runs fine with the 5.3 computer minus the SES light. I am also using the original tranny. Another wierd thing happens now. When I shift the tranny from "3" to "D" the starter engages. With the truck off if I hold the shifter in between "3" and "D" I can actually start the truck. I am at a loss here. I have checked all the wires I can and I can't find any that might be pinched causing a short and I have no idea why the tranny now won't work when it worked fine before.

I am in desperate need of help,

Adam

 

So, you are using the harness , computer, & trans from the truck? The only thing changed is the motor correct? I would say something is pinched or maybe a connector reversed, go over everything assume nothing.................

 

My first advice would be to check all the grounds.

 

Sounds like you've got some wiring issues. But none of that will cause the trans not to go into gear. I would double check the shift linkage.

 

You are correct, the only thing "new" here is the motor and it is an '05 6.0L. It even has the driverside fuel rail, x-over tube and oil pressure sender from the old motor. I have checked and re-checked the connectors about 20 times now and have traced dang near every wire in the harnes. Like i was saying early the motor runs like a champ starts up like it should and purrs like a kitten when idling. I can put it in gear and the dash says its in gear but nothing. It still acts like it is in Park/nuetral.

Thanks for the help, please keep it coming.

Adam

 

I have tried this also, with no luck.

Adam

 

Did the torque converter slip out of the pump when you removed the engine?

 

Yes, but I got it slid all they way back in. I used the flexplate from the old motor. When I went to bolt the plate to the TC it did seem to have an excess amount of space in there around 3/16" gap.

Adam

 

Hopefully the tc got seated all of the way, or your front pump may be damaged which would explain the trans not going into gear. The starter engaging in 3-D is interesting though, that has to be some sort of short...

 

is the tranny pumping fluid? pull a hose off.

6L have a different flexplate spacing