383 to 4l80e to np208

[Brad]

New user here, I have been perusing the various forums for weeks now looking for a fairly solid answer and just can't seem to find it. I have smoked 4 700r4 transmissions over the past 2 years and am finally moving up to a 4l80e platform. Questions abound, my main question is will a bowtie overdrive 4l80e bolt up to my np208 after adding a 32 spline to the transfer case? Advance adapters sell many types but that exact adapter isn't listed on their site. Is this possible? I have an autometer electronic speedo from transfer case signal so that part isn't a worry. I know i will need a standalone computer and to move the assembly rearward. Just want to make sure all the puzzle pieces will fit and if i need extra parts or where to find them.

 

[Brad]

Man... tough crowd

 

[Georgeb]

It's been kinda quiet here lately. I am sure someone will chime in soon.

 

[Camar068]

Looks like your in the right direction. You need 32 spline, you may have to shave a bit off the output shaft of the trans or take up the slack with a clocking ring. As for the adapter, it sounds like the np205 adapter may work and may/may not need a bit of machining. Info found in the 2 links at the bottom.

What gearing are you running? I've got an LS/4l60 to drop in with the NP208 with 3.08 gearing. Come to find out the 4l80 will handle the stress a lot better than the 4L60. So I'm highly interested in this....unless I figure out how to get a 6L80 in it LOL.

Also a good idea to email Advanced Adapters. They have some adapters that aren't listed using their sort tool on the left side of their site.

Few links I found by googling:

http://www.pirate4x4.com/forum/chevy/2197697-how-4l80e-np208.html

http://www.pirate4x4.com/forum/chevy/2197697-how-4l80e-np208.html

https://www.google.com/#q=4l80+to+np208

Hope this helps

 

[Brad]

Thanks y'all, looks like the 205 and 208 adapter is synonymous according to advance. The tranny I got was a 2x4 and will be using a "spud" to connect the 2. Will post pics when I have everything on a bench. Wish I knew my gearing, always figured i would mess with that when my corporate popped but 33" tires and 500 torque just won't kill it. Best I can tell is stock for that year. Anyone have experience with TCI vs compushaft? Bowtie recommended compushift but my wallet is leaning towards the 1/2 off TCI.
Camar068, that 6l80e really interested myself also. Just doesn't seem to have enough aftermarket support for me to be comfortable with it yet though :/

Thank you for the help

 

[Brad]

Starting the build

Finally got the trans this week, starting the process tomorrow. Ended up getting the bowtie overdrive, TCI computer, and keeping the 208. I'll try to keep the process up to date

 

[bucket]

I'm curious, did they not offer a trans with the 4x4 output? Then you could just bolt up a stock 241 adapter and put a 32 spline 208 behind it. Or a 241 of course.

Who makes the spud shaft?

 

[Brad]

I think any number of combinations is possible, including shaving the output shaft on the transmission to accommodate the 208. I think this particular setup, hopefully, only needed a gm 4x4 adapter that was $125 and the output shaft that was also $125. I'm sure i will find surprises in the coming day once everything is out and next to each other. Worst case scenario, I have to buy the advance adapters $700 kit to make this work where it will be real easy to talk myself into buying an atlas case instead and start calling my truck a tank.

 

[Derick C.]

I will be following this thread. I need to do the same swap in my burb

 

[Brad]

in other news, if anyone is near Austin Tx looking for a 700r4 K case (thicker aluminum) transmission with expensive internals i've got one. Obviously needs a rebuild, but better than starting from scratch.

 

[Jrgunn5150]

You can convert a 411 PCM into a stand alone controller for the 80.

 

[Brad]

already dropped the pennies on the tci, thank you though

 

[Brad]

making some progress, got everything out of the truck and on the floor. Should be way easier than i thought to be honest. Here's a few pictures to show some reference. Just gotta pop off the adapter on the np208, change out the shaft, and connect the 2.

You must be registered for see images attach

You must be registered for see images attach

You must be registered for see images attach

 

[Brad]

here's a few of the rest of the truck. 3rd engine, 5th trans now, 1 t-case rebuild...

 

[Brad]

Ok, got everything in on working order. I have a 2 wheel drive 4l80e with an np208 transfer case. We added a new 32 spline shaft to the transfer case and a clocking ring (or spud connection) to mate the 2. With a 4" suspension lift, the driveshaft was the perfect length stock so no alterations there. TCI comp was replaced once, but finally started shifting second correctly.