I get confused on this topic. However in your case you might have had a 6.0 that had the shorter crank. I believe that was a 99 6.0 iron block and heads that had that issue and was only used with a 4l80e. Now if you have an engine that was not equipped with an 80 originally and you do not have a custom converter with the ls1 pilot, then a spacer is needed so the pilot for the converter is supported. I could be wrong but that is my understanding. Feel free to correct me here but I build transmissions not build trucks. Vince B

 

I'm scratching my head on the subject, have no idea why it happened the way it did, but the converter is seated all the way, the flexplate came from GM with the spacer and bolts already installed, so no way to screw up the way it goes on. and without the spacer, the starter would be engaged all the time... if the flywheel could even bolt up that way being it's flat, not dished like the 65e flexplate. The converter is the factory converter that came on this 4L80, everything pointed toward a direct bolt up, but there was just no go. I used the bellhousing spacer and it's working so far, guess I will see.

I found a driveline shop open this morning and brought the whole shaft in. I ended up with a th400 1350 Yoke that worked like a charm. My truck has 1350 u-joints in all 3 locations, don't know if it is because of the LQ9, the 4L65e, or the 14 bolt rear end, but for whatever reason, my SS comes factory with 1350s, not the 3R like I thought it would have.

 

I have a feeling because your truck has some of the HD features such as the 14 bolt rear end, the swap isn't the same as it would be for a pure 1500 2wd truck unfortunately.

 

 

Well, no leaks, clean shifts, fingers are crossed but all seems well at this point. The taller first gear that so many worry about is a non existant issue. The fact that the stock 4L80E TC stalls to about 2500 rpm is more noticeable than the taller first gear.