After doing so many swaps and builds I thought I got this one down but apparently not.

Everyone seems to reiterate the same thing, that is, LS engines had two flanges on the crank, early 99-00 4.8/6.0 had the longer flange and later 01+ engines had the shorter one. Except I have two engines here sitting on the stand that are neither of those.

Let's first look at what we already know. This is the longer flange crank that came on early 4.8/6.0 trucks.




And this is the shorter flange that requires a spacer when used with older transmissions.





Now this what I have on two of my engines. One is a 2005 Gen 3 LQ4 from a 2500HD Silverado with factory NV4500. The other is a 2012 Gen 4 L76/L77 from a Chevy Caprice with factory 6L80e. What the hell is this supposed to be?

 

Does it have a place to mount a starter on the block?

 

Yes both engines use a standard LS starter.

 

I've never messed with the front wheel drive engine but that is what my first thought was but I also thought they didn't have a starter boss on the block. Does the block say 6.0 or 4.8/5.3?

 

They're both RWD 6.0's. LQ4 is an iron block, L76 is an aluminum.

 

Ok, I'm confused, You have three pictures so what did the one with the odd crankshaft come out of ? I'm guessing the two you listed.

 

I think you missed what I wrote describing each image. This is what I wrote for the third image.

 

LOL you've found an intermediate bizarro crank flange

 

Lol but seriously I can't be the first one with this issue?

 

That's a stardard crank flange. The difference is the seal in the rear cover. Take a closer look.

 

The rear cover is the same part and the seal is seated all the way in both pics. What am I missing here?

EDIT: For further reference I have a third engine (2004 5.7 LS1) also on a stand. It has a crank flange that's flush with the seal exactly like the 2nd pic. What gives???

 

Your seal in the 3rd pic is sitting inside of the cover and doesnt have the same outward lip as the other pics.

Measure the difference between the cover itself and the end of the crank.

 

Is that a crank spacer on the first image or actually part of the crank? The crankshafts in the older motors such as the LQ9's do not require a spacer to attach an older style transmission. I believe the difference is like 0.33 but not 100% positive on that but if you do have the older version crank then you do not need to run the spacer or aftermarket flex plate which has the difference already built into it.

 

In the last image it looks like the rear seal was installed backwards.

 

This...two different seals in the last two pics...same rear cover. Look at it closely.

 

Or one went in backwards as has been mentioned

 

We have a winner. Somebody out there shouldn't be installing seals anymore...

 

I'll take some pics of my engines later today. One is a low miles LQ4 that's never been opened before and looks like the 3rd image.

 

Pics of the engine aren't going to help.

Measure from the face of the cover to the end of the crank on all engines.
Fix your rear seal.

 

In the end, it's not even the distance from cover face to crank that really matters--it's the depth between the bellhousing mounting flange and the end of the crank. Just run a straightedge between two of the mounting bosses and get a depth measurement. As others have said, though, it just looks like the normal "short" crank with an incorrectly installed rear seal.