Made A Choice Of Of Transmission By Going With A 4L80E For A 1983 Chevy Suburban C20 454 Dually

[blackandgold51]

Is that 1 of the 2 Suburbans from Sherman?
If so, I talked to the seller and remember him thinking it had 4.10 gears. It was quite some time ago & my memory isn't what it used to be.

454/4L80E with 4.10's is a good combo.
Just got back from a 2,800 mile trip hauling a car & averaged 9.5 or so mpg.
The truck is a little newer and fuel injected (L29) and I have a 34" tire (4.56's would be perfect for this set up)

Yep , that's the same Suburban. From Sherman Texas, I had it shipped here to New Orleans.

He had or may still have another Suburban Dually he tried to sell which was a 3/4 ton with a 350tbi and 4x4 but I took the red instead, besides I don't use 4x4 much and he charged me less for the red than the other. He mainly wanted get rid of it

I forgot the guys name, but yeah same suburban from Craigslist.

I think he also had a green one too that he tried to sell.

And the red suburban was not originally from Texas, it was actually in Georgia before being brought to Sherman, Texas , which now its here in New Orleans.

And yes, the 454 with a 4L80e and 4:10 is a good combo. Before I do anything else along with a new paint on the body that turbo400 gots to go!

Mechanical first, body second

 

[blackandgold51]

GM highlighted the "55" mph on the dash cluster in red or orange due to that being the national speed limit when the truck was new --every older GM truck I have owned was the same way..

I need to pull the diff cover off my K2500 and see just what ratio gears it has--its weird,around town it seems very high geared,its rather sluggish taking off,especially if you stop on a steep grade ,and it stays in second up to 45+ mph before it sounds like its starting to wind out--but at 65 mph on the highway,it sounds like its spinning much closer to the 3600 rpm redline,and I don't like driving it at that speed or any faster for fear it'll fly apart..I "guessed" it has 3:23 or 3:42 gears,but it might surprise me and end up being 3:73's or 4:10's..
I have never had the diff cover off in the 15 years I've owned it,and I wont be surprised if it has never had new gear oil put in it,or if anyone else ever had it off..

Like the guy above said, it's 4:10 gears. Which I don't want to lose that gear just in case when I to tow heavy, so I'll go with that 4l80e , and drop that gear into "D" instead overdrive when its time to tow.

Or maybe I may drop from 4:10 to 3:73 for a little economy but not to much for some heavy towing ........

 

[blackandgold51]

Well we can figure it out.
What gears do you have and what size tires.
I am running 37" with 4.88 and a th350 so when I hit the highway at 75mph I was turning 3600 rpm, I knew it would not be good since the shroud on my radiator was cut when they did the body lift, sure enough after 20 minutes temperature started to rise, it got pretty close to 250 I eased off and it didn't get back down till I got to 65mph.
I need to put the 700r4 in mine.

Like the guy above me said which is right, it's got 4:10 gears

 

[acm]

I think you got the better of the two trucks from what I saw. Never looked at them though...but a dually burb is always cool.

 

[blackandgold51]

Is that 1 of the 2 Suburbans from Sherman?
If so, I talked to the seller and remember him thinking it had 4.10 gears. It was quite some time ago & my memory isn't what it used to be.

454/4L80E with 4.10's is a good combo.
Just got back from a 2,800 mile trip hauling a car & averaged 9.5 or so mpg.
The truck is a little newer and fuel injected (L29) and I have a 34" tire (4.56's would be perfect for this set up)

I like that picture you got, from ,

I think you got the better of the two trucks from what I saw. Never looked at them though...but a dually burb is always cool.

Thanx, it gets me where I got to go.

As for the gears I'm keeping the 4:10, especially when going up the hill it keep it in that 4th gear(overdrive ) without dropping to 3rd.

As for Dually Suburbans there's some out there still on Craigslist which the best to go. Or build one, Dually rear end and fenders.

I was going to do that with the last one which was a GMC 1990 Half Ton 4x4 with a 700r4 and 350tbi. But I didn't have time for it and sold it and got big red

 

[black dawg]

When I added overdrive to my big block suburban, I gained 1 mpg. It made it much nicer to drive, but would never pay for itself in less fuel usage

 

[1-ton]

I do not know if you plan on rebuilding your 4L80E or just throwing it in as is, but the 4L80E does have known issues that can be fixed. One modification that is done to improve the performance and reliability of a 4L80E is a thing called "dual feeding". There are other known issues as well with the valve body bores wearing out that can be fixed. I am sure somebody is going to call me a dumbsh!t that does not know what I am talking about for posting this. It happens every time I post anything.

 

[blackandgold51]

I do not know if you plan on rebuilding your 4L80E or just throwing it in as is, but the 4L80E does have known issues that can be fixed. One modification that is done to improve the performance and reliability of a 4L80E is a thing called "dual feeding". There are other known issues as well with the valve body bores wearing out that can be fixed. I am sure somebody is going to call me a dumbsh!t that does not know what I am talking about for posting this. It happens every time I post anything.

Nope. Not throwing it in, rebuild first and going in at a local transmission shop

 

[1-ton]

Nope. Not throwing it in, rebuild first and going in at a local transmission shop

Chances are that any trans shop is not going to do anything over and above a basic rebuild. Most trans shop builders do not have the time or patience for researching and reading all the material there is on fixing known problems with the 4L80E. A basic rebuild will still last you several years before the over-pressure problems that the 4L80E is known for will blow the trans. I had to rebuild my own 4L80E in order to make sure all the known weak points of the 4L80E where fixed because I know transmission shops will not want to mess with any small details of getting the 4L80E right. Most of the weak points of the 4L80E are minor fixes that require tearing the whole trans down, and after they are fixed the 4L80E is bullet proof.

 

[blackandgold51]

Chances are that any trans shop is not going to do anything over and above a basic rebuild. Most trans shop builders do not have the time or patience for researching and reading all the material there is on fixing known problems with the 4L80E. A basic rebuild will still last you several years before the over-pressure problems that the 4L80E is known for will blow the trans. I had to rebuild my own 4L80E in order to make sure all the known weak points of the 4L80E where fixed because I know transmission shops will not want to mess with any small details of getting the 4L80E right. Most of the weak points of the 4L80E are minor fixes that require tearing the whole trans down, and after they are fixed the 4L80E is bullet proof.

You are correct, there are shops out there that , like you said, don't want to take time to research and repair the problems and instead want to do a quick wamb bam repair and rebuild for quick cash grab

 

[sweetk30]

i have even seen so-called pro shops not even pre-soak the clutches . . . seen them install them dry

when i asked why not they said when you fire it up the fluid get to them just fine .

 

[imiceman44]

i have even seen so-called pro shops not even pre-soak the clutches . . . seen them install them dry

when i asked why not they said when you fire it up the fluid get to them just fine .

That's not good.
My guy taught me to soak the clutches overnight.

 

[eodcoduto]

I just priced out a US Shift controller, holy crap! Over $800 for a simple computer? There has to be a way to program an arduino or even a cheap Samsung tablet to run that transmission.

 

[sweetk30]

I just priced out a US Shift controller, holy crap! Over $800 for a simple computer? There has to be a way to program an arduino or even a cheap Samsung tablet to run that transmission.

that is not a simple controler . did you read up on i and all its options / 4 stored shift on the fly programs / so on and so on . . . .

never read 1 thing bad about them even back when the name was optishift . the company split off and made a new sub division now us shift .

i have one not installed yet . good looking quality . mrk5 has one . few others have it also .

 

[sweetk30]

That's not good.
My guy taught me to soak the clutches overnight.

i was told fan them out / cover in fresh fluid / 30 min re-fan out to get covered spots . then if no bubbles good to go .

 

[eodcoduto]

that is not a simple controler . did you read up on i and all its options / 4 stored shift on the fly programs / so on and so on . . . .

never read 1 thing bad about them even back when the name was optishift . the company split off and made a new sub division now us shift .

i have one not installed yet . good looking quality . mrk5 has one . few others have it also .

I agree it does an awesome amount of work, but when you look at a controller for a 30 year old transmission costing that much it took me by surprise. We are building robots and drones at work and it is amazing the amount of magic these small Arduino and Raspberry Pi boxes can do for under 100 bucks. I’m not the one to do it but I bet someone on here can program one to run a transmission.

 

[imiceman44]

I agree it does an awesome amount of work, but when you look at a controller for a 30 year old transmission costing that much it took me by surprise. We are building robots and drones at work and it is amazing the amount of magic these small Arduino and Raspberry Pi boxes can do for under 100 bucks. I’m not the one to do it but I bet someone on here can program one to run a transmission.

I agree that it is a little too much.
I am sure it's because they can not because it costs that much.
There are other ways much cheaper including some toggle switches for manual control and then like you said some electronic platform programmable to link them into more user friendly.
Luckily I have a 454tbi with the 4l80e and the original wiring and computer so I can at least have it run.
Until I find a cheap way to do better than stock.
I didn't even pay that much for my whole setup with the np241

 

[blackandgold51]

I just priced out a US Shift controller, holy crap! Over $800 for a simple computer? There has to be a way to program an arduino or even a cheap Samsung tablet to run that transmission.

Ha

I just priced out a US Shift controller, holy crap! Over $800 for a simple computer? There has to be a way to program an arduino or even a cheap Samsung tablet to run that transmission.

Well we can figure it out.
What gears do you have and what size tires.
I am running 37" with 4.88 and a th350 so when I hit the highway at 75mph I was turning 3600 rpm, I knew it would not be good since the shroud on my radiator was cut when they did the body lift, sure enough after 20 minutes temperature started to rise, it got pretty close to 250 I eased off and it didn't get back down till I got to 65mph.
I need to put the 700r4 in mine.

Tires are LT245/75/R16s all around

I think it's 33 inches of the tires and 4:10s in the rear.

I do daily drive the vehicle on mixed city, along with the in-city overpass bridges doing 50 to 55 in the 60mph traffic slow lane, and once or twice a week 50 to 55 on the 70mph interstate from East New Orleans, Louisiana to West Slidell, which is a 26 minute drive and back on 10 dollars of unleaded fuel.

As for city driving on the grounds/street which is 35 to 40 mph mostly . Buy even in the 40 mph speed limit areas I stay under 35 in general . I don't drive like a maniac and take my time. Even the police such as the NOPD and Louisiana State Police pass me up lol

There are a couple of bridges that connects mid downtown to the new orleans east area which includes an elevated bridge and the larger interstate, in-city 60 mph , bridge .

454 carburated/turbo400/ dually rear end with 4:10s/LT245,75,R16s/

I might post a video of the acceleration and shift points in action on this thread