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bkahler · 09-06-2012, 10:15 AM

Currently there is a freshly built Turbo 400 transmission sitting in my 1974 Argosy motorhome (no engine installed at the moment). We bought the Argosy with a 350 engine installed although it had never been ran before.

I also have a used 4L80E transmission from a 1992 (I think) chevy box truck that had a 350 motor in it. The truck was scrapped because the engine compartment caught on fire. If I do use the 4L80E in the Argosy I will definitely have it gone through before installation. I did pull the computer from the box truck when I pulled the transmission and I've been led to believe that the computer will require that a few sensors be added to the 454 Argosy engine so the transmission will shift correctly.

One of the questions I have is will the computer that I pulled from the box truck work with the 454 engine that I have? Or will I need to find one that was used in a 454 application?

Another question is are there any upgrades, etc that should be done to the 4L80E as it is being rebuilt?

Which sensors will need to be added to allow the 4L80E to function properly with the 454?

Any other tips or suggestions?

Thanks!

Brad

overlander63 · 09-06-2012, 10:40 AM

Brad, you will have to put nearly every sensor on the 454, and you will probably have to install fuel injection as well.
Oxygen sensors, throttle position sensor, coolant temp sensor, ambient air temp sensor, crank position sensor, knock sensor, it'll be a major thing. The computer for the 5.7 won't work on the 7.4, they are different and the engine and transmission won't work right.

Chipster · 09-06-2012, 11:21 AM

I have an 86 chev crew cab 4x4 dually. We installed a cummins turbo diesel engine with a turbo 400 and everything worked great, also we have a gear vendor installed. Now the update--- after about 150K miles the 400 needed a rebuild. We found a 4l80e and put it in place of the turbo 400. There are companys that sell stand alone computers that will adapt that trans to any computer controlled or non-computer controlled engine. It is not any big thing. Thats what we did and it is still going strong after 300K miles. The cost is around $1000. One company is called Compu-shift. Give them a call. Having the gear vendor and the 4l80e is a great combo and we are very satisfied. Don't be discouraged, you will love the result with the lock-up torque converter and the overdrive, just do it! Happy trails, Chip

bkahler · 09-06-2012, 11:34 AM

Wow Terry, way to rain on my parade

I guess I need to dig a little deeper to see exactly what year/model the transmission is and what year (for certain) that the truck was. I would hope that I could use the computer part number to determine what features it needs or doesn't need.

I'm certainly not adverse to switching it to fuel injection either.

Dang, more to think about

Brad

195Pilot · 09-06-2012, 11:44 AM

In another life I was a District Service Manager for GMC Truck . The THM400 was the strongest transmission GM ever produced. That tranny will preform with little input from engine, and again its as close to bullet proof as you can get.
With the thm400 you can keep it simple.

bkahler · 09-06-2012, 01:20 PM

Quote:

Originally Posted by Chipster

I have an 86 chev crew cab 4x4 dually. We installed a cummins turbo diesel engine with a turbo 400 and everything worked great, also we have a gear vendor installed. Now the update--- after about 150K miles the 400 needed a rebuild. We found a 4l80e and put it in place of the turbo 400. There are companys that sell stand alone computers that will adapt that trans to any computer controlled or non-computer controlled engine. It is not any big thing. Thats what we did and it is still going strong after 300K miles. The cost is around $1000. One company is called Compu-shift. Give them a call. Having the gear vendor and the 4l80e is a great combo and we are very satisfied. Don't be discouraged, you will love the result with the lock-up torque converter and the overdrive, just do it! Happy trails, Chip

Chip,

I've heard of these aftermarket companies. Probably the only concern I would have using an aftermarket part like this would be failure while out on the road. What do you do about repair service or are they that robust you don't have to worry about it?

Brad

bkahler · 09-06-2012, 01:23 PM

Quote:

Originally Posted by 195Pilot

In another life I was a District Service Manager for GMC Truck . The THM400 was the strongest transmission GM ever produced. That tranny will preform with little input from engine, and again its as close to bullet proof as you can get.
With the thm400 you can keep it simple.

I can't argue your logic on the dependability of the 400. Unfortunately I really like the idea of having an over drive to drop the rpms and increase mileage.

What I'm hoping is since a 20' Argosy motor home only weighs about 8500 lbs or so the 4L80E should actually be overkill.

Thanks for the feedback.

Brad

dirigible25 · 09-06-2012, 01:44 PM

go online and check out companies like Gear Vendors (www.gearvendors.com) or TCI (www.tciauto.com) and they all have products for many various applications, computers, cables, transmissions and any other product that you would require to swap in various transmissions to different engine combinations. They have been around the street rod market for years with very good reputations and warranties. There are others out there as well. They have good technical service folks who would be glad to talk over your particular needs and steer you in the direction that you need to go.

ElCamino Man · 09-06-2012, 03:21 PM

Its far from a bolt on upgrade. Youll need a big block bell housing to start with, and a different tranny crossmember, shorter driveshaft, AND a stand-alone controller. I did a similar upgrade to my El Camino, I know all about it lol. What you will gain is an overdrive meaning improved mpgs! Youll have some cash wrapped up in this upgrade for sure

overlander63 · 09-06-2012, 04:46 PM

Honestly, it would probably be easier and cheaper to get a Gear Vendors overdrive unit and install that.

Waipio Rim · 09-06-2012, 05:31 PM

Has anybody thrown a higher geared differential at this problem? Seems like it would be easier and cheaper, but I might regret it the first time I came to a mountain.

Mike Leary · 09-06-2012, 05:51 PM

Quote:

Originally Posted by Waipio Rim

Has anybody thrown a higher geared differential at this problem? Seems like it would be easier and cheaper, but I might regret it the first time I came to a mountain.

Our first mo/ho was a 28' Excella diesel. The PO had done the same thing, trying to get better highway speed. When we pulled hills, I could walk faster.

ElCamino Man · 09-07-2012, 07:55 AM

Whats wrong with your current set-up? Are you just trying to gain mpgs?

bkahler · 09-07-2012, 05:28 PM

Quote:

Originally Posted by dirigible25

go online and check out companies like Gear Vendors (www.gearvendors.com) or TCI (www.tciauto.com) and they all have products for many various applications, computers, cables, transmissions and any other product that you would require to swap in various transmissions to different engine combinations. They have been around the street rod market for years with very good reputations and warranties. There are others out there as well. They have good technical service folks who would be glad to talk over your particular needs and steer you in the direction that you need to go.

Dennis,

Thanks for the links. The last time (4 years ago?) I looked into transmission controllers the ones I found seemed like they were well over $1000. TCIAuto shows one at about $600. That's a lot closer to what I would be interested in.

Thanks!

Brad

bkahler · 09-07-2012, 05:36 PM

Quote:

Originally Posted by ElCamino Man

Its far from a bolt on upgrade. Youll need a big block bell housing to start with, and a different tranny crossmember, shorter driveshaft, AND a stand-alone controller. I did a similar upgrade to my El Camino, I know all about it lol. What you will gain is an overdrive meaning improved mpgs! Youll have some cash wrapped up in this upgrade for sure

I wish I could say money is no object but that certainly isn't the case

Needing a different crossmember is something I don't remember hearing about before. I'm assuming the shape is different for the 4L80E compared to the 400 and I'm guessing it is also farther back. Would getting a crossmember from a truck that had a 4L80E in it get me in the ball park? I'm not to worried about any fabrication that might need to be done. I'm fairly handy in that regard.

For some reason I thought the bell housing was integral to the transmission and the bolt pattern was the same for 350's and 454's.

Brad

bkahler · 09-07-2012, 05:39 PM

Quote:

Originally Posted by overlander63

Honestly, it would probably be easier and cheaper to get a Gear Vendors overdrive unit and install that.

Terry,

I would think I could come in cheaper using the 4L80E and doing most of the work, rebuild, etc myself that buying a gear vender overdrive, and I really like the idea of a lock up torque converter.

Now if you have a gear vendor unit lying around that you don't need...

Brad

bkahler · 09-07-2012, 05:50 PM

Quote:

Originally Posted by ElCamino Man

Whats wrong with your current set-up? Are you just trying to gain mpgs?

Probably nothing wrong with it. However the motor is out and and there ever was a good time to change setups this would be it. Plus the one in the motorhome right now is a TH400, not the TH475 as used in the motorhomes.

As I mentioned earlier I really like the idea of a lock up torque converter and getting better mpg is definitely something to think about.

Plus I just like to tinker

Brad

Mike Leary · 09-07-2012, 06:22 PM

We blew our 475 Turbo Hydra years ago, found a funky, family transmission shop in Idaho. He checked it out and said he could have a rebuilt in a couple of days, and then he'd have to tear it down to re- program it for the diesel. I sort of shrugged, and then he said, "if you've got some time, I can build you a bad boy." I went with him, he used all the Allison parts he could get his hands on, short story: best transmission I've ever had, all the shift points are smooth and at the right RPM.!

Waipio Rim · 09-07-2012, 09:19 PM

Originally Posted by ElCamino Man
Whats wrong with your current set-up? Are you just trying to gain mpgs?

Our 310 turns about 3,000 rpm at 60 mph and we get about 7 mpg on a good day. It just seems like going one tooth higher in the differential would slow the motor down and give us better mileage, but judging from Mike's experience it might mean a lot more first gear driving in the mountains.

bkahler · 09-08-2012, 08:43 AM

Quote:

Originally Posted by Waipio Rim

Originally Posted by ElCamino Man
Whats wrong with your current set-up? Are you just trying to gain mpgs?

Our 310 turns about 3,000 rpm at 60 mph and we get about 7 mpg on a good day. It just seems like going one tooth higher in the differential would slow the motor down and give us better mileage, but judging from Mike's experience it might mean a lot more first gear driving in the mountains.

Interesting. I've never paid a whole lot of attention to mph vs rpms but I seem to recall that I'm not much over 3000 rpm when I'm traveling around 65 or better. Of course this assumes that the instruments are correct. Sometime in the next month or so I'll take the rig out and use the gps for speed and hook a tach/dwell meter to the coil to see what is actually going on. Our mileage is above 7 mpg when towing and closer to 9 when we aren't.

When in the mountains on the steeper grades pulling the race car on a trailer we frequently drop down to around 50 mph but on the flats we can easily do 75 pulling the race car and trailer.

Our engine does have the Banks Power Pack.

Brad