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07 tbss awd
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Correct it’s a custom piece. It’s never been a unicorn piece though it’s been available for a long time from Phoenix transmissions in Texas (not to be confused with Phoenix racing transmissions) Problem is there isn’t any information anywhere about who makes it and where to get it. And you can’t order from the site you have to call.

I’m sure Pete’s is probably cheaper, however Phoenix was a pleasure to deal with just the same.

If it were me I would have the t case front half modified by Pete and ditch the adapter all together. Had I known this was an option I would have used it all along. That way you don’t loose spine engagement or have to get a 2wd output shaft cut down to the correct length. And frankly the t case is already getting moved far enough back with an 80 without the additional 1/2-3/4” with the adapter.

And if your worried about taking the tcase apart don’t be this thing is as simple as can be inside.
 

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TrailblazerSS
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Discussion Starter #82
I don`t know what is all this nonsense about spline engagement.
This shaft of mine is exact copy of OEM but with 32-splines. Splines are as long as OEM.
So you get plenty of engagement, period.

No need to get this swap over complicated, I would not personally do any potentially weakening and expensive transfer case machining and welding of any sort.

All you need is 4L80E 6-Bolt Transfer Case Adapter part# 15654927 (or equivalent) from your local junkyard, craigslist etc.
And adapter plate to connect it to your transfer case. Any competent machine shop can make you one.

Thats that.
 

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TrailblazerSS
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You gain spline engagement when modifying the transfer case to bolt directly to the 4l80, since you're doing away with the adapter plate. Its only a little under an inch, but it's still more engagement, as well as one less piece involved in the setup.

Sent from my LM-X210CM using Tapatalk
 

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07 tbss awd
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The spline engagement concern comes from adding an adapter/spacer between the transmission adapter and the transfer case.

You’ve now spaced the transfer case around 3/4”further away from the transmission than a stock 4l80 4wd setup.

So my output shaft is a full spline 2wd shaft cut down to be about 3/4” inch longer than a stock 4wd shaft. This was Phoenix transmissions recommendation based on the measurements they use to make their kit with a turned down 27 spline shaft.

Granted I took some measurements with my case taken apart and I think a stock 4l80 4wd shaft would have enough engagement into the adapter.

What I should have measured and didn’t is output shaft stick out between a 4l60 4wd and the 4l80.
 

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TrailblazerSS
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Discussion Starter #86
You gain spline engagement when modifying the transfer case to bolt directly to the 4l80, since you're doing away with the adapter plate. Its only a little under an inch, but it's still more engagement, as well as one less piece involved in the setup.

Sent from my LM-X210CM using Tapatalk
The spline engagement concern comes from adding an adapter/spacer between the transmission adapter and the transfer case.

You’ve now spaced the transfer case around 3/4”further away from the transmission than a stock 4l80 4wd setup.

So my output shaft is a full spline 2wd shaft cut down to be about 3/4” inch longer than a stock 4wd shaft. This was Phoenix transmissions recommendation based on the measurements they use to make their kit with a turned down 27 spline shaft.

Granted I took some measurements with my case taken apart and I think a stock 4l80 4wd shaft would have enough engagement into the adapter.

What I should have measured and didn’t is output shaft stick out between a 4l60 4wd and the 4l80.
All this is extra welding and/or case machining completely unnecessary.
If you don`t think stock 4x4 4L80E output shaft will give you enough spline engagement, measure it, and then here is what you do....or just do this in the first place....

Jup, just like Phoenix does, you take stock 9" 4L80E output shaft and cut it to length you need, thats it.
This way you get MAXIMUM spline engagement no matter how thick your adapter plate and extension housing is.
No welding nor case machining needed.
 

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TrailblazerSS
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Discussion Starter #87
Or if you buy your 4L80E from Rossler Transmission, he can make you billet output shaft any length you want;)
 

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TrailblazerSS
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Mine has a billet output shaft, but it's the stock 4x4 length. That's why I like the modded transfer case. Especially with one less piece in the mix.

Sent from my LM-X210CM using Tapatalk
 
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