4L80E question

[SteelNinja]

I was reading discussions on using a 4L80E without a computer ( going full manual) but my question is will it bolt up to a 6.2? and I believe it will bolt to my transfer case but I may be wrong. anyone used a 4L80?

 

[Iceman3005]

Yes a 4l80e will bolt up. I did it on my CUCV. You will need an adapter for the np208. Fabtech sells them. You can use the turbo 400 flex plate. The shifter location is farther back. You will need to drill new holes in your frame to move the shifter mount back.

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[Iceman3005]

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[Iceman3005]

Pics of adapter.

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[Barrman]

The cross member is a super easy fix. The rear frame bolt hole becomes the new front hole. Then just drill the new rear hole in the frame with the crossmember as the template.
You also need to think standard and metric. The 6.2 is all metric. The TH400 is standard. The NP208 is metric as is the 4L80E. Which means the pedestal for the NP208 is sized in standard dimensions on the transmission size. That is just a hair too big to mount up to the metric 4L80E. I have very gently used a hand file to make the pedestal fit the 4L80E.
The shift rod will also have to be lengthened 2 inches.
I used the Compushift controller and love it. Having different driving modes easily selected was a big g thing for me. Basically my own tow/haul button.

 

[SteelNinja]

Thanks for all the help. Im going with the 4L80E because I want more top end without changing ring and pinion.
Is there a way I can save this thread so I can find it when needed?
also Ive thought about putting a turbo kit on the 6.2 , the dude who is trading me a 4L80 also has a 6.5 turbo engine with 29k miles- so now I need to figure what is best in that regards. I paid large dollars for my 84 Dually - completely rust free , looks very nice - But I thought the engine was just noisy - but its a rod knock. I asked the dude I got it from and he said that's why the original owner didn't want it . ( so dude got me) ..I took a loan to get the truck ( I needed a good truck for work) and now Im making a payment on a truck that's knocking...So its time to work some OT and get the truck 100%
I greatly appreciate all the help

 

[SteelNinja]

will the driveshafts need cut and or extended?

 

[Iceman3005]

Yes the drive shafts have to be cut. The 4l80e is longer.

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[Rutjes]

I'm looking into a 4L80E swap(s) as well. I have already bought one and so did my friend. Is your truck lifted? If I remember correctly, I've read where people who had about a 4" lift did not need to change the rear driveshaft length?

I used the Compushift controller and love it. Having different driving modes easily selected was a big g thing for me. Basically my own tow/haul button.

Just the other day I was putting together kits at the HGM website. Do you have the "new" Compushift? Sport and Pro?

 

[Rutjes]

Yes a 4l80e will bolt up. I did it on my CUCV. You will need an adapter for the np208. Fabtech sells them. You can use the turbo 400 flex plate. The shifter location is farther back. You will need to drill new holes in your frame to move the shifter mount back.

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An adapter like this one?

 

[Iceman3005]

GM 4L80E to TH400 NP205 Adapter/Spacer Kit

This is our 4L80E to TH400 Pilot Adapter/Spacer Kit. CNC Machined in House from 6061-T6 Billet Aluminum. This adapter is used when replacing a TH400 with a 4L80E. 1979-1984 TH400 to Fig.8 NP205 will require a 2wd 4L80E. (Short 2wd 6-1/4" Stick-out requires the Output Shaft to be trimmed 1-1/8")...

www.northwestfab.com

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[Iceman3005]

An adapter like this one?

https://www.northwestfab.com/4l80E-to-TH400-NP205-AdapterSpacer-Kit_p_3452.html

That's the one you need.

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[Rutjes]

Thanks. Googling "fabtech 4l80e adapter" did not come up with that. Not sure if I like that though. If spending this much money on swapping in a 4L80E, why not spent the extra 100 or so bucks for the ORD adapter instead of adding a spacer.

 

[Iceman3005]

Thanks. Googling "fabtech 4l80e adapter" did not come up with that. Not sure if I like that though. If spending this much money on swapping in a 4L80E, why not spent the extra 100 or so bucks for the ORD adapter instead of adding a spacer.

Your np208 is not a figure 8 bolt pattern.

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[Rutjes]

Your np208 is not a figure 8 bolt pattern.

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Always thought the NP205 and NP208 were interchangeable. Thanks for clearing that up.

 

[Barrman]

My controller is not the sport comp one. It was their latest and greatest 4 years ago. Before I bought, I called up my final 3 or 4 choices to talk about my 6.5 turbo Suburban project and how their controller would work. Computech was the only one that actually answered the phone. It might not be a one man operation, but the guy I talked to in several phone calls was the guy who built them, boxed them and did customer service. I was impressed.

Kind of apples and oranges. But my Suburban with an ORD add an inch in front and ORD 2.5 inch shackle flip in the back is still running stock drive shafts after 21,000 miles.

 

[Barrman]

Forgot to add that through our talks. Computech knew all about my truck. He had pre programmed the controller for everything. A true plug and play install with me only having to zero the throttle position input.

 

[SteelNinja]

Ive started a logbook on any and all info I can collect on this topic and other.. I really appreciate everything.

 

[Skinny]

I thought you said you were going manual valvebody? If this is the case you dont need a computer...just a manual valvebody. May want to consider a vacuum modulator mod so you dont have full line pressure all the time. Also a lockup converter is better then none.

If you decide to go with a computer you have plenty of options. I used a US Shift 4 and like it a lot. No one tells you that regardless of computer you need to find a way to route a rather large plug through the body.

I ran the stock CUCV cooler in the rad and it sucked. Immediately ran up to 260 degrees. I installed a stand alone Tru Cool with 3 8" e-fans which keeps it around 200.

All things to consider...

I also saw you wanted to go turbo. So why not just find a 6.5 driveline and add a DB2 pump and 4l80 controller? You will get an AC compressor, serpentine belt, the 4L80 is already attached, and it has the turbo on it. Lots of extras.

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[Iceman3005]

Nothing wrong with a manual valve body, but honestly if you drive the vehicle often, manually shifting an automatic will probably get old after a while. Now for controllers of you choose to go that route. I went with TCI. Nothing wrong with other controllers, I liked the easy installation, has several modes to choose from that can be done while driving. Like stock, tow, race mode. It automatically changes shift points, firmness, etc. For you. Or you can put it in custom mode and setup shift points, etc. That suite you. I also liked the fact that in normal mode it adapts shift points, etc. To your driving style without any manual input. There warranty is also very good. Plus they have great customer service in my opinion. I had to call them for a problem I was having, they helped me solve it over the phone!

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