Question, ajrothm, gkull
Thread Starter
Le Mans Master
Joined: Apr 2006
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Question, ajrothm, gkull
I have a 55 series 1 3600 3/4 ton pickup with the original 235 and sm420 trans. Rear ratio 4.57 tires 31 dia. And the granny low first gear 7.05. Have decided going to put a sbc in it put in a 4L80E. Is there a paticular company you would recomend to get the trans from ?
Team Owner
Joined: Apr 1999
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From: Reno Nevada
2024 C3 of the Year Finalist- Modified
With the economy since 2008 many of the performance builders closed down. The 4l80E has lots of hidden costs that people don't think off. Like the HGM Compushift controller for transplant applications. You have to have a controller for …….E, which stands for electronic transmissions. Then you buy a higher HP unit for say $2500 - $3000. You then need a $1000 TC and they might also have a $650 core charge. So what seemed like a good deal is up to $5000.
another consideration when deciding on a auto tranny type is how much HP does it eat up. when you start putting in bigger pumps within a tranny type...…. it takes up more hp. I didn't even think of that when I when from a stage 3 or 4 TH350 to full out racing 800 hp 700R4. I was into drag racing and my built up TH350 limped home with busted metal chunk in the pan. So I bought the built 700R4. I immediately lost .3 seconds on a 12.00 previous car. It wasn't just the gearing of the 700. It was the additional 25 hp that the tranny was eating up.
The 4l80E is like a OD th400. You start adding the ability to withstand 800 hp and you really have a power sucker compared to a 700 or even a 200 which is lesser of a drain.
another consideration when deciding on a auto tranny type is how much HP does it eat up. when you start putting in bigger pumps within a tranny type...…. it takes up more hp. I didn't even think of that when I when from a stage 3 or 4 TH350 to full out racing 800 hp 700R4. I was into drag racing and my built up TH350 limped home with busted metal chunk in the pan. So I bought the built 700R4. I immediately lost .3 seconds on a 12.00 previous car. It wasn't just the gearing of the 700. It was the additional 25 hp that the tranny was eating up.
The 4l80E is like a OD th400. You start adding the ability to withstand 800 hp and you really have a power sucker compared to a 700 or even a 200 which is lesser of a drain.
Drifting
Joined: Jun 2012
Posts: 1,990
Likes: 183
From: Port St. Lucie Fl
find a running and driving 3/4 ton truck/van 96-01, it will have a sbc and the 4l80, if you swap in the efi you now have your tcm. This will also require an adapter to a tcase and modifying your drive shafts. Using a th350 or 400 may not require modifing your driveshafts.
Stock 4l80s are rated to 450tq if you exceed that then get an upgraded one.
Stock 4l80s are rated to 450tq if you exceed that then get an upgraded one.
Le Mans Master
Joined: May 2006
Posts: 9,993
Likes: 1,136
From: League City Tx
I have a 55 series 1 3600 3/4 ton pickup with the original 235 and sm420 trans. Rear ratio 4.57 tires 31 dia. And the granny low first gear 7.05. Have decided going to put a sbc in it put in a 4L80E. Is there a paticular company you would recomend to get the trans from ?
I would get a built 4L80e from Jakes Performance.
Call him and tell him what you are wanting to do and he'll spec it out for you. He is pretty much the "go to" for 4L80s. I'll likely be getting one from him myself in the next year or so.
http://www.jakesperformance.com/4l80/
That's pretty much the only option for something that will get worked hard and make a bunch of power.
Thread Starter
Le Mans Master
Joined: Apr 2006
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Not going to be racing it but would like a rugged trans for the 3/4 ton to haul an rv trailer with and it will be a daily driver. Have had the turbo 400s in my first 72 vette to different 3/4 ton pickups they were always reliable. The stock engine around 135 hp and just going to build a mild 350 in the 375/400hp range. Far as i know it will need some form of stand alone computer to shift it, the engine will just be old tech carb stuff.
Last edited by Little Mouse; Aug 2, 2019 at 03:47 PM.
Thread Starter
Le Mans Master
Joined: Apr 2006
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Rats $5600.00 i want to spend more like $2500.00 tops or less. The around 2.50 low gear combined with the 4.57 gives a hair over 11.1 overall low gear that works, need an overdrive to knock the 4.57 down some more. Current tires are 31 dia. And in the back i could go bigger dia. Maybe it will have to be a regular turbo 400 and bigger dia. rear tires to save cost. A simple cant fail lokar shifter.
Last edited by Little Mouse; Aug 2, 2019 at 04:51 PM.
Thread Starter
Le Mans Master
Joined: Apr 2006
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know nothing about it, how it works or price. But i do have to start from scratch and buy a trans. Buying both probably not worth it. I suspect my best option just to go regular turbo 400 and use large dia. Rear tires. Right now it has 235/85 16 at all four corners a little over 31 in dia. Im sure i could go 33 on the back without and fender mods. Guess i need to go to wallace calculator and figure out how much a 33 tire is knocking down the engine revs. 4.57 rear in a car with say 26 dia. Tire would be a blast to drive stop light to light with no overdrive. But without having an overdrive a 33 dia. Tire should go a long way to making it more freeway reasonable.
Last edited by Little Mouse; Aug 3, 2019 at 12:50 AM.
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Le Mans Master
Joined: May 2006
Posts: 9,993
Likes: 1,136
From: League City Tx
Really a stock 4L80 would do what you want to do fine. Looking for a junk yard take out trans, then buy the aftermarket controller and harness from PCS, Compu Shift or the other ones. I bet you can do it all for $2500 or less.
Thread Starter
Le Mans Master
Joined: Apr 2006
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Ya nothing cheap anymore, stage 1 turbo 400 looks to be around $1500 at most companies, then say $400 for hughes tq converter, another $200 for a lokar shifter then say $150 for a good trans cooler. You gave me some good options on places for parts, thanks. Might even consider if it could be found a good used turbo 400 and $260 worth of new bigger dia. Rear tires. Right now the rims and tires previous owner put on the rim is about a fingers width clearance on the tie rod ends. One of the original tires and rim is mounted on the left side bias ply tube 6.50 16 with the death trap lock ring rim. The SM420 iron case and 7.05 low gear considered strongest 4 speed made and lowest 1rst gear. There very popular for rock crawler crowd. Trans is only 10 1/2 long, top loader with center mounted shifter.
Last edited by Little Mouse; Aug 3, 2019 at 04:44 PM.
Drifting
Joined: Jun 2012
Posts: 1,990
Likes: 183
From: Port St. Lucie Fl
Rats $5600.00 i want to spend more like $2500.00 tops or less. The around 2.50 low gear combined with the 4.57 gives a hair over 11.1 overall low gear that works, need an overdrive to knock the 4.57 down some more. Current tires are 31 dia. And in the back i could go bigger dia. Maybe it will have to be a regular turbo 400 and bigger dia. rear tires to save cost. A simple cant fail lokar shifter.
Thread Starter
Le Mans Master
Joined: Apr 2006
Posts: 5,403
Likes: 95
I once got away with buying a $50.00 turbo 350 out of the junk yard replaced all the seals and put it in my cousins 54 vette. Summit racing has B & M turbo 400 street/ strip trans for $1120.00. Thinking i will go this rout. As much as i like the .075 overdrive 4L80E not a fan of computer running things, something else to fail cause me grief.
Last edited by Little Mouse; Aug 4, 2019 at 01:02 AM.