91 4l80/241 diesel into a 85 5.7/700r ?

[liftmeup]

Hi, lucky me I went to the junker this morning to find another 7004 to rebuild for my 85 as mine is on the way out (4x4) and as I'm walking the yard a guy tows in a 91 suburban !! score ! I took the front core support and all with harness to swap into my truck, It was a diesel with huge hole in oil pan so I would say engine death was what ended its life. I pulled the trans and t-case out of it already and got them. The yard owner told me come back monday if I want enything else he had to close up at 11 for the day.

My question is what else do I "need" from the suburban to make this work ? I assume just start following the wires and get everything thats connected to the trans from one end to the other ?

I know I will need a gas engine converter for sure no big deal.

Thanks I have been into these truck forever but new to swaping a 4l80 in.

 

[HotRodPC]

Oneluckypops is the one to help out on this gig. He's arare of the pinout and the changes that need to be made to get the 4L80-E to work. But, are you getting the ECM and all out of this Burb? Or did the Burb have the 700r4 K Case core? The best 700r4 core you can get btw.
So are you going with the 4L80-E or the 700r4?

 

[HotRodPC]

Whoa wait a minute. Hold the Phone !!! First off, welcome to GMSB liftmeup. I like'm lifted too, fat chicks can't jump. But, before we help anyone around here, we require pics of your truck. I'm already jealous. I have K10 and K1500, but apparently going to have to convert one of them to have a 20/2500 but I'm gonna do it. I'd actually prefer a K30 but people want to much for those unless they've robbed the D60 from it.

 

[liftmeup]

If I can use the 4l80e out of 91 without to much trouble I will. otherwise just rebuild a 700, they have 2 89's burbs there with 700 trannys and one had beautiful clean fresh fluid , and a ton of reciepts from repair work in the glove box so most likely it was loved.

 

[HotRodPC]

It can be done, but keep in mind, you WILL have to have a ECM of some sort to be able to have the electonics to operate the 4L80-E. Or, there are aftermarket stand alone ECMs like Compushift, but man, they are expensive. Close to $1000 just for the computer and harness to make it work as a stand alone.
Are you a trans builder too? Are you aware on the years that you should prefer. One of those 89 700r4's should be a good choice for a build too. 88-92 4x4 K case will be your best choice to use as a core. Or, even use it till it breaks then build it with some recommeded mods to make it more durable.

 

[liftmeup]

maybe I will just get the 700 and plop it in for now and hold the 4l80e for a rainy day...

 

[GreaseDog]

why not snag the harness and controller from the Burb, hook it up, and run it? diesel 80Es come from the factory with what is basically a standalone controller, like the copmpushift.

 

[liftmeup]

see those are the things I need to know

 

[oneluckypops]

why not snag the harness and controller from the Burb, hook it up, and run it? diesel 80Es come from the factory with what is basically a standalone controller, like the copmpushift.

To run a electronic Transmission behind a carbeurated engine is going to be a chore, Honestly depending on what you use your truck for it may or may NOT be suited for you.

The electronic transmissions will need a few different sensors to operate correctly, UNLESS you want to go full manual control, (no longer automatic).

1. TPS Sensor to measure throttle angle
2. ECT Sensor to measure engine temperature (ya its a factor in how it shifts)
3. MAP Sensor to measure engine load
4. ISS Sensor to help with Transmission slip speed, and shift points
5. OSS Sensor ALSO to help with Transmission slip speed, and shift points
6. Also need a tach input or Crank sensor to the computer
7. Brake Switch to control converter lock up

The diesel harness will work just fine but you will have to adapt the sensors from it to your gasser. Probably would not be that difficult. One thing that WILL NOT work is the torque converter you will have to have a converter for a gas engine, Also the computer will need the gas engine shift points programmed in it.

IMO the compushift harness is for ******* that are scared of alittle wiring, You can build your OWN standalone system from any harness, GAS or DIESEL.

The only other thing that your going to have to deal with is driveshaft lengths, The Rear will need to be shortened 1 5/8", the Front will need to be lengthened 1 5/8".

Now a piece of advise for you. BEFORE you commit to doing this conversion beaware that the 4L80E has a HIGH first gear ratio (248:1) versus the 700R4's 306:1. So if your planning on running the 4L80E make sure you regear your Differentials to ATLEAST 410's. Any higher that that and you will not be happy with the performance, mileage, OR the durability.

I am currently installing a fuel injected 5.7 vortec with a 4L60E in my 85 K30. I took a motor, transmission, harness, and computer from a 96 and modified the harness to be basically a stand alone harness. All i need now is time to get the whole thing finished, but when your running 80-100 hours a week it doesnt leave much time to work on it.

If you have anymore questions feel free to let me know.
Welcome to the forum, But be aware of that HOTRODPC he can come off as a "know it all" LMAO

EDIT: Oh **** ya you got a K20 more then likely you already have 4.10's but double check it before you start.

 

[HotRodPC]

Welcome to the forum, But be aware of that HOTRODPC he can come off as a "know it all" LMAO
.

Hey Lift, pardon me for a minute while I borrow your thread to slap the **** outta pops.

I don't know it all, never claimed to, but do know alot. And for the things I don't know, I usually KNOW who the go to person is who will know and can get the info. Uhhhh, kinda why I suggested ******** here for info on the 4L80-E pinout and info.

 

[GreaseDog]

One thing that WILL NOT work is the torque converter you will have to have a converter for a gas engine

wrong, the diesel converter will work just fine. especially if you plan on using your K20 like a K20.

Now a piece of advise for you. BEFORE you commit to doing this conversion beaware that the 4L80E has a HIGH first gear ratio (248:1) versus the 700R4's 306:1. So if your planning on running the 4L80E make sure you regear your Differentials to ATLEAST 410's. Any higher that that and you will not be happy with the performance, mileage, OR the durability.

the 4L80E will have a higher 1st gear, and a lower OD... either way, you'll have no problems with any kind of durability.

 

[oneluckypops]

wrong, the diesel converter will work just fine. especially if you plan on using your K20 like a K20.the 4L80E will have a higher 1st gear, and a lower OD... either way, you'll have no problems with any kind of durability.

Converter for the diesel will not bolt to his flw wheel. Stall speeds are different aswell.

Yes the 4L80E has a higher first gear ratio, 248:1 and anything less then 4.10's WILL create to much slippage and heat causing failure. It's the same goes with tire sizes (final drive ratio)

 

[oneluckypops]

Hey Lift, pardon me for a minute while I borrow your thread to slap the **** outta pops.

I don't know it all, never claimed to, but do know alot. And for the things I don't know, I usually KNOW who the go to person is who will know and can get the info. Uhhhh, kinda why I suggested ******** here for info on the 4L80-E pinout and info.

ahhhh come on now ******** just wanted to have a little fun lol

 

[HotRodPC]

ahhhh come on now ******** just wanted to have a little fun lol

I knew that. I do know everything, but I don't want anyone else knowing that. My PM box fills up fast enough as it is.

 

[liftmeup]

ok tuff guys . Lets keep it.. ah **** it I love entertainment lol..