Ok, sorry for the delay on the update. The crank was NOT broken, just broke the center out of the flywheel. I found that after I got the motor out Oh well, I enjoy pulling this motor every month or so!

I found a couple probs so hopefully it wont happen again. And I went ahead and put my forged motor back together so it is going back in with a fresh 4l80 and a Yank pro 3400. We will see in a couple weeks, I guess.

Anyways, I have learned that the 6 liter spacer and flywheel is necessary with the 4l80. I was running the 5.3 flywheel with no spacer. It will physically work, but what I didn't know is that the spacer not only serves as a spacer, but also as a crank pilot extender, effectively extending the rear of the crank, giving the converter snout something to center into. So my converter was centered on nothing but 3 little bolts and at almost 7000rpm it needs to be perfect!

My other prob was that I have been trying to run a trans case that was busted into 8 pieces at one time and was welded back together. It is evidently not 100% inline with the motor and that is causing major probs.

I should be back in business soon.

 

Is that 6.o flywheel the same as the 5.3? I would think the spacer would be the only change needed, but I need to know for sure since I will be doing this very thing soon.

 

Flyer, No-the 6 liter flywheel is flat and uses a spacer. The 5.3 flywheel has curvature made in it so that the starter ring gear comes out in the same place as the 6 liter flywheel does with the spacer. So yes, the 5.3 flywheel will work with a 4l80, but like I said, not advisable cause of the pilot issue.

 

The reason for the flywheel change is to keep the teeth lined up with the starter. They bow the flywheel differently; otherwise when you add the spacer you would be moving the flywheel teeth away from the starter.

It would be a shame to go thru all the work of the changeover and then just hear the starter zing but not engage.

 

I was thinking that would be possible then I read it. I'll keep that in mind if I ever go to a 4l80.

 

Wow .. some more great info! John, I'll be contacting you probably next week about the harness. I will send you my ls1edit file if Allen can't help me out with it, I still haven't talked to him about it yet though.

L-Eater .. sounds like you had some messed up stuff going on. That's good advice for the next guy.