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Discussion Starter #1
Greetings,

What I have is a 4x4 4L80E with a short (approx 3-1/2") output shaft. What I am looking for is a stout t-case with a pass drop with an overall length that is as short as possible.

I currently have no adapter or stock t-case.

The best option that I have come up with is stock adapter & the rare 6 bolt 32 spline pass drop NP205.

Aftermarket adapters that I have seen to go to other t-cases seem to need the long output of a 2wd transmission.

I do have a 10 spline figure 8 NP205 that I could make fit, but looking for other options I may not have thought about.

Ideas?????
 

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GM only put the NP205 behind the 4L80E for a year or two. I didn't think it took a special 205, but rather a special adapter....... but that's only from reading, not from experience. Anything from a GMT-400 on, will be drivers side drop. So you're limited to whatever else, if anything, GM put behind the 4L80E in the squarebody trucks, or an after market adapter, I believe. Sorry, I can't give better help.
 

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Discussion Starter #4
Thanks Gents,

"I didn't think it took a special 205, but rather a special adapter" ...

What I understand is the bolt pattern on the 205 needs to be the 6 bolt pattern, AND you need the 4L80E to 205/241 adapter. Another option, I think, is the same adapter plus a 6 bolt to figure 8 adapter, to fig 8 case.


"What about an Atlas t/case...you can have those built for whatever you want to use it for. "....

The Atlas adapter that Advance sells uses the long 2wd output shaft. My 4l80e is a new transmission so I really do not want to have it torn apart to swap output shafts plus it is a longer adapter. Not to mention the cost of the Atlas, plus adapter, plus shaft, plus shifter.
 

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when i first got my m-1010,i put a 4l80 overdrive trans in,to replace the stock thm-400...i installed an np 205 as well.i was able to use the 205 racetrac style case and the thm-400 adapter.the output housing of a 4l80 and the 400 are virtually identical...with one fortunate exception...the indexing ring on the 4l80 is a few thousands smaller than the one on the 400.

you need a 205 with the short 32 spline input,a ractrac adapter,and the 4x4 "short" output on the 4l80.measure the outer diameter on the adapter indexing ring,and compare it to the 4l80 output housing.on mine i was able to have about 30 thousands shaved of the diam' of the adapters indexing ring,so it matched to the 4l80 output housing.(the bolt holes match up)...next,the out put on the 4l80 needed a quarter inch removed from the end...and it all bolted together.

this will save you from a possibly friutless search for a round style 205 case.the racetrac style is very common and cheap.also,the adapter that was used between the 4l80 and 205 in factory apps' is a rare beast...iv'e only ever seen one,and it required a round input case with the long 32 spline input.
 

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Discussion Starter #6
Thanks a lot, that is exactly the info I was looking for on the 205.
 

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this is also known as turning a $500 job into a $4000 job.
yup...the atlas is a great case,but the money can go to much better things,imop...i was able to get mine together for under 350 bucks,including all the parts,machine work,a hi milage 205,and a rebuild kit for same.saved a ton of coin doing everything but the machine work myself...
 

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Greetings,

What I have is a 4x4 4L80E with a short (approx 3-1/2") output shaft. What I am looking for is a stout t-case with a pass drop with an overall length that is as short as possible.

I currently have no adapter or stock t-case.

The best option that I have come up with is stock adapter & the rare 6 bolt 32 spline pass drop NP205.

Aftermarket adapters that I have seen to go to other t-cases seem to need the long output of a 2wd transmission.

I do have a 10 spline figure 8 NP205 that I could make fit, but looking for other options I may not have thought about.

Ideas?????
i have a 4L 80 out of 99 GMC 4x4 130000 miles on truck was asking $ 700
 

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Not the best place to put a for sale item. You did notice that the last post on this thread was 8 years ago?
 
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