Chevrolet 1984 K30 Dually - Restoration

[Isajel]

Hello,

I am currently doing a restoration on a 1984 Silverado pickup. It currently has a 6.2L Detroit Diesel with a bank turbo, which is paired up with a TH400. I am hoping to do a swap on the transmission to one that has overdrive, as I was hoping to go above 55 without possibly causing damage. So moving on, the idea is what would be a better option: getting a TH700r4 and dealing with the shorter transmission, which would need an extension, and having to deal with a TV cable. The other option I was thinking of would be a 4L80e, which will require a computer.

Thank you

 

[Valley Rock]

Taller tires and leave it alone ?

If I had both trans at my disposal and I had to change it out, I'd definetly go with the 4l80 and a stand alone .

But I really like them old TH-400s, I cant even fathom removing one to put a 700r4 in its place .

 

[Isajel]

Alright, if I were to go with a 4L80e what would I need to make the shifting work properly without having the modern engine with it? Would I only need the stand alone controller or anything else? Then again would it even be worth all the trouble just to get overdrive?

 

[owensexport]

I put a HMMWV 4L80E in my 1986 Suburban with a bone stock 350CI engine.
Used the TCI standalone computer.
Installation was not too difficult, Make sure to buy the correct flex plate to
match your new Torque converter.
One challenge was the shifting linkage, I wanted everything to remain
original looking. Wound up using some parts from a Tahoe and the original
linkage merged together.
Cross member is easy, just drill new holes about 3 inches rearward.
Lengthen front drive shaft / shorten rear driveshaft.
Transfer linkage was just a weld up to make it longer.
Cooling lines were probably the most challenging, I wound up just making
them from premade piping sections from the auto parts store.
Functionality: FANTASTIC!
I have had multiple CUCV's and Civilian square bodies, I would never
go back to building a truck with a TH400, not worth the effort.
Its such a pleasure to be able to cruise at 70 mph and not hear the engine scream.
If the rig is a keeper for you, spend the money and make it so you can
enjoy driving it for the rest of your ownership

 

[Barrman]

This has come up a bunch. Basically it comes down to which way you want to spend money.

There are many places on line and I’m sure someone local to you that can build a 700R4 to be a very dependable long lived transmission. You will have to change the input shaft on the 208 transfer case or get a different 208.

A 1995 or newer 4L80E can be had pretty cheap. But, you have to buy the standalone controller. I went with HGM electronics for my turbocharged 6.5 Suburban.

The total spent worked out pretty close when I ran the numbers 7 years ago for my build. I went 4L80E because I planned to tow and it was made for that instead of being built for that.

Do as you wish. The 400 is the most cost effective heavy duty automatic out there and you already have one. Bigger tires as suggested above really is a valid suggestion.

 

[Valley Rock]

Then again would it even be worth all the trouble just to get overdrive?

Not to me, but it aint my truck .

If it was my truck I would remove the gutless smoke maker and drop a 454 in the same hole and add a 2" or 4" lift and taller tires and done .

The Mark IV engine will comfortably rev 2k higher and the engine trans combo will live trouble free longer than the Chevy body will last, and you will enjoy your truck exponentially more .

I dont want a computer running my trans in an older rig like that, hell I don't even want it running the trans in my SD .

But, that's just me

Take your time in weighing your options, build it how you want it with simplicity in mind would be my thoughts .

 

[Isajel]

I was really considering doing an engine swap along with it, either a 6.0 Vortec or a 454, but before that, I would need to wait for a good deal to appear.

Regarding the transmission, I will wait until I decide on the engine and consider if the time and money are worth it to me, as either way it will be a lot to consider. Then again, I would hate to have to deal with a computer, as it becomes a pain, and I only have to deal with mechanical issues right now with the system I am running.

For now, I will probably work more on the smaller items in the restoration and leave the expensive items last. Regarding bigger tires, it was an option I was considering, as either way I do have to replace all six tires as the ones I have now are cracked badly.

 

[Isajel]

Progression


Here's a late progression on the truck, but this is what I have currently and what it started as.
I had started the progress awhile ago, but I ended up deleting it, so I might as well make a new one.




At the beginning, I had gotten it from my dad, who had used it as a dump truck, so it was in horrible shape.



One of the first things I did was attempt to deal with the engine, which was leaking oil and having a rough idle, so after
Working on that, fixing only one of the issues, I decided to paint it.




I had done a paint job on it alone, but after realizing how horrible it was, I decided to seek help from the local body
shop, and they told me how to handle it, so following their advice, I started to work on each panel alone, getting
them to perfection through bodywork. In the process, I gutted the entire truck and removed all the body panels.




So far, the passenger side is the only body panel I have finished that is ready for painting. The current body component
I am working on is the cab, which has been gutted and removed. For all the panels, I will be sandblasting them and
starting fresh to get them show car perfect. I will need to locate a new door as the driver side I had was rusted and
a waste of time to patch as well as both fenders and most of the bed.

So far, that's what I have accomplished. It was slow progress as I came in knowing no idea what to do, but after time
and help, I started to understand.