4L80E swap questions.

[454Sub]

Ok, I have gotten (for free) all the engine wiring, fusebox, computer, dash/gauge wiring, and a 4L80. This all came out of a 1990 4wd 3/4ton Suburban with a 350. I am wanting to swap this into my Suburban. Mine originally was a 1990 1/2ton 2wd with a 350. I put this body on an 1980 frame. It runs an injected 454 to a 400/205 with a slip yolk. So mine has no speed sensor of any sort. (I know I know bad ju ju). Anyways, so Im looking over my new found loot, and I noticed the new fusebox has a fuse marked "tranny". Of course, mine with the original 700r4, does not have that in the fuse box. So it seems I will have to swap out the entire harness. Which I dont want to to, but cant be helped. Im using this tranny to calm down my 5.13s on the road a bit and at the same time get a slightly lower first gear, I need an excuse to put a speed sensor in, and to gain a little bit of front driveshaft length.

My questions are...

Who sells an adapter to mount the 205 to the back of a 4L80 or will it bolt straight up, which I doubt since my luck is that good?

Can said adapter be used with the factory 205 crossmember?

I have a Dodge fixed yolk 205, can I use the parts off it for my Chevy one so I can finagle a speed sensor in it?

And being a 90, what am I going to have to mess with to get the speedo to read correctly? I know the tranny needs the speedo input to shift correctly and I know it cant be as easy as pulling out the gear and swapping a new one like on the old cable driven systems.

As of now, I am running a chip for a factory 454 with a manual. So Im going to need a chip as well to control the tranny, plus my 454 has an intake, headers, ported heads, bored TB, and a aftermarket regulator. So I know its not running right, as the block learn and all that isnt what its supposed to be. So I either need, A a bible for tuning these things, as I have never burned chips, or B, someone to do it for me. (nothing wrong with dreaming right?)

 

[nvrenuf]

Since you don't have a lot invested yet ( ).... There are stand alone controllers and manual valve bodies to get around having to swap the fuse box / harness.

Also, a '85+ 400/205 short adapter can be modified to fit the 4L80e, search SweetK30's posts for a how-to thread about this.

 

[454Sub]

I thought about the stand alones, but they are the definition of pricey. And another reason I want to swap harnesses is mines kinda blah, and I just finished washing up underhood wiring, and its perfect, no cuts or splices anywhere, and mine has tape all over hiding who knows what. So Im tryin to prevent future heartache by swapping that part over. Thanks alot for the adapter info, I have one of them laying around as well.

 

[sweetk30]

not pricey unit and few guys here run it. use to be called opti shift . http://www.usshift.com/index.shtml

and its the 84-older fig 8 style 205 i did with my 4l80-e to 2o5 case with 1.25" spacer .

85-up some guys make spacer also to install it between tranny and adaptor.

th400 rear seal lip for adapor is 1 size. but 4l80-e is a little diffrent so watch out for that.

and best to start off with 2wd tranny and run it as 2wd for stupid easy use . but can do 4wd and make sensor out of a 231-241 style sensor and modifyed tone ring and drill/machine/tap sensor hole in tail of 205.

divorced 205 and ford 205 use 32 spline front outputs . and dodge / gm share same rear tail housing so swap over should be fine.

fyi 4l80-e didnt start till 1991 so make sure you have a 4l80-e not a th400.

and all the 4l80-e to 205 info is here . http://coloradok5.com/forums/showthread.php?t=166233&highlight=4l80

 

[454Sub]

Yea, it was my brothers old truck. Mine and his are both very late model 90s, so basically they are 91s.

Wouldnt the 2wd case shift funny in 4wd?

Mines an 80 400 with the 205, and then i have to make the 1.25 spacer separately?

 

[rksjd8420]

Northwestfab has a 0.6" spacer/adapter that goes in between a 4L80E and the factory TH400/NP205 adapter. Part # BA-4L80e-400. It has the correct indexing ring and spaces the adapter back so it will not hit the transmission oil pan.

If you are using the long input shaft NP205 (typically late 85-91) you need to use the 3 inch 4x4 output on the 4L80E. If using the short input NP205 you need to use a 2wd output on the 4L80E. You may have to cut it down a little. I think it needs to be about 5" long.

It is usually easier to just run a speed sensor off of the back of the 4L80E. 2wd transmissions already have the sensor and reluctor ring in the transmission. Some 4x4 4L80E's have the reluctor ring and some don't. The older ones usually do and the newer ones usually don't. If it doesn't you have to tear it down and add it but that is usually easier and better than most other methods.

 

[Kstanbach]

I thought about the stand alones, but they are the definition of pricey. And another reason I want to swap harnesses is mines kinda blah, and I just finished washing up underhood wiring, and its perfect, no cuts or splices anywhere, and mine has tape all over hiding who knows what. So Im tryin to prevent future heartache by swapping that part over. Thanks alot for the adapter info, I have one of them laying around as well.

http://www.msgpio.com/manuals/mshift/4L80E/4L80.html

I'm surprised this setup doesn't get mentioned much.