6l90E 2wd 36 spline to 27 spline drive coupling idea??? - The 1947 - Present Chevrolet & GMC Truck Message Board Network

NDM · 02-09-2024, 12:21 AM

I am curious why this idea that I have would not work. Please check my proposed idea.

I have my 72 that is getting a Gen V L8t 6.6 swap. Currently I am 4x4 but my new trans is 2wd 6l90e. I know I could find a 4x4 trans. I know I could convert the 6l90e to 4wd. But..... why could I not simply buy a new 27spline to 27 spline th350 to np205 drive coupler for about $50 and take it to a machine shop to have it resplined to 36 spline (to match the 6l90E). Then simply fabricate the required spacer/ adapter tube to bolt the two together like the timberline no cut adapter kit (1800 bucks). I am a welder/ fabricator so the adapter is not a problem.

Here is the replacement drive sleeve but I can get one much cheaper elsewhere. https://www.offroaddesign.com/drive-...27-spline.html

I am trying to retain the ability to go back to my SBC 350 in the future if I so desired. Once I machine my np205, no going back. Also, I really want to run my 6l90E. The modern motor and trans have 25k miles and were from the same truck. I am building a daily driver with the option for some future owner to go back to the OEM parts if they want to.

Why would my idea NOT WORK?

Here is the timberline adapter tube thing that I would fab up on my own.
https://timberlinesupply.com/product...conversion-kit

NDM · 02-09-2024, 12:29 AM

Fyi, for anyone wondering why not just buy the timberline kit.
1. It is $1800
2. It still requires machining the np205.
3. It comes with a male/female adapter and I need a female/female adapter.

Also, the parts and tools required to convert my 2wd 6l90e to 4x4 is about $400. I could pay the machine shop and still have cash for the material required to build the adapter tube for $400.

NDM · 02-09-2024, 11:57 AM

Anybody???

**HO455** · 02-09-2024, 08:46 PM

You might try posting your question in the 4x4 section or the LS swap section. You might have a chance of finding someone who did it but not for a 67-72. And give it some time many of us don't check the site daily.

NDM · 02-09-2024, 09:25 PM

Quote:

Originally Posted by HO455

You might try posting your question in the 4x4 section or the LS swap section. You might have a chance of finding someone who did it but not for a 67-72. And give it some time many of us don't check the site daily.

You are 100% right. I should have thought about that!

NDM · 02-09-2024, 09:30 PM

I reposted this thread in the 4x4 area. Mods you can delete this one if you like.
reposted this thread in the 4x4 area. Mods you can delete this one if you like.

02-09-2024, 12:21 AM	#1
NDM Registered User Join Date: May 2022 Location: Illinois Posts: 223	6l90E 2wd 36 spline to 27 spline drive coupling idea??? I am curious why this idea that I have would not work. Please check my proposed idea. I have my 72 that is getting a Gen V L8t 6.6 swap. Currently I am 4x4 but my new trans is 2wd 6l90e. I know I could find a 4x4 trans. I know I could convert the 6l90e to 4wd. But..... why could I not simply buy a new 27spline to 27 spline th350 to np205 drive coupler for about $50 and take it to a machine shop to have it resplined to 36 spline (to match the 6l90E). Then simply fabricate the required spacer/ adapter tube to bolt the two together like the timberline no cut adapter kit (1800 bucks). I am a welder/ fabricator so the adapter is not a problem. Here is the replacement drive sleeve but I can get one much cheaper elsewhere. https://www.offroaddesign.com/drive-...27-spline.html I am trying to retain the ability to go back to my SBC 350 in the future if I so desired. Once I machine my np205, no going back. Also, I really want to run my 6l90E. The modern motor and trans have 25k miles and were from the same truck. I am building a daily driver with the option for some future owner to go back to the OEM parts if they want to. Why would my idea NOT WORK? Here is the timberline adapter tube thing that I would fab up on my own. https://timberlinesupply.com/product...conversion-kit Last edited by NDM; 02-09-2024 at 12:32 AM.

02-09-2024, 12:29 AM	#2
NDM Registered User Join Date: May 2022 Location: Illinois Posts: 223	Re: 6l90E 2wd 36 spline to 27 spline drive coupling idea??? Fyi, for anyone wondering why not just buy the timberline kit. 1. It is $1800 2. It still requires machining the np205. 3. It comes with a male/female adapter and I need a female/female adapter. Also, the parts and tools required to convert my 2wd 6l90e to 4x4 is about $400. I could pay the machine shop and still have cash for the material required to build the adapter tube for $400. Last edited by NDM; 02-09-2024 at 12:35 AM.

02-09-2024, 11:57 AM	#3
NDM Registered User Join Date: May 2022 Location: Illinois Posts: 223	Re: 6l90E 2wd 36 spline to 27 spline drive coupling idea??? Anybody???

02-09-2024, 08:46 PM	#4
HO455 Post Whore Join Date: Feb 2016 Location: Portland Oregon Posts: 11,526	Re: 6l90E 2wd 36 spline to 27 spline drive coupling idea??? You might try posting your question in the 4x4 section or the LS swap section. You might have a chance of finding someone who did it but not for a 67-72. And give it some time many of us don't check the site daily. __________________ Thanks to Bob and Jeanie and everyone else at Superior Performance for all their great help. RIP Bob Parks. 1967 Burban (the WMB),1988 S10 Blazer (the Stink10 II),1969 GTO (the Goat), 1970 Javelin, 1952 F2 Ford OHC six 4X4, 29 Model A, 72 Firebird (the DBP Bird). 85 Alfa Romeo If it breaks I didn't want it in the first place The WMB repair thread http://67-72chevytrucks.com/vboard/s...d.php?t=698377

02-09-2024, 09:30 PM	#6
NDM Registered User Join Date: May 2022 Location: Illinois Posts: 223	Re: 6l90E 2wd 36 spline to 27 spline drive coupling idea??? I reposted this thread in the 4x4 area. Mods you can delete this one if you like. reposted this thread in the 4x4 area. Mods you can delete this one if you like.



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