Overdrive Swap Economics

[BigBlocksRule]

Doing something similar on my '85 with a 454.
$305 gets you a new TBI wiring harness set up for the 4L80E. Computers are cheap, so are TBI units and adapters. I have a 70K mile 4L80E that came from a wrecked truck, I paid $250 for it, changed fluid and filter and I'm going to run it as-is. The one in my current work truck has 235K with nothing more than occasional fluid/filter changes. Add a cooler if you're going to tow and that's about it. Mine is a dual tank truck, I scavenged the switch, tanks, etc. off of a parted out truck so I can use 'em both.
Don't make it more complicated than it already is!!!

[Ford Assassin]

Originally Posted by Rogier

I've spent so much more on trashing 700's that were advertized to be able to handle 1000HP etc. I've not been able to buy a 700 that handles my modest 400HP engine in the mountains with 6 guys and a loaded truck. After multiple broken 'custom' 700's I gave up. This 4L80E has not let me down thus far and has improved my economy to about 14mpg coming from 11.

I couldn't agree more. I don't care what has been done to 'allow' the 700R-4/4L60e to 'handle' more than 400HP and any type of load or abuse, its not a matter of 'if', its a matter of 'when'.

Too many times I talk to guys who spent loads of money on their 'bulletproof' 4L60e and a short time later I am hearing about broken this or broken that in the trans and the builder all of a sudden won't warranty it due to its 'nature'.

Although the overdrive is deeper on the 4L60e (.70) vs the 4L80e (.75) and the 4L60e doesn't 'eat' as much power compared to the 4L80e, I'll take a 4L80e over a 4L60e almost all the time.

[BigBlocksRule]

Even with all the upgrades, the 4L60E is still a weak design. I'll spend what it takes to have a reliable OD tranny for towing and the only one that fits the bill for me is the 4L80E. Now for daily drivers with small blocks that aren't used for towing, the 4L60E is fine, IMHO.

[Ford Assassin]

Originally Posted by BigBlocksRule

Now for daily drivers with small blocks that aren't used for towing, the 4L60E is fine, IMHO.

True, I have own three GM B-Body cars (full size) and all three had the 700R-4, with regular fluid changes, none failed. The second one had over 300,000 miles before I sold it.

Even now my daily driver, 2008 Trailblazer SS has the most updated version of the 4L60e, called the 4L70e behind the LS2. Beyond a cold air intake, custom tune, and a Trans-Go HD2 shift kit after the powertrain warranty expires (5 Year/100,000 Mile), it will be left alone since I know I'd end up killing the 4L70e sooner or later. Right now its bone stock minus a Magnaflow muffler.

[SSC's76]

its all going to boil down to what you want. its not cost effective to do this swap if it were me id wait until the th400 died before I would consider this swap unless the truck sees alot of miles does not sound like this one does.


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[68Timber]

You guys are talking me out of a Bowtie Overdrive 700R4. I know I'm going to flog it regularly and add spray at some point, I don't need a $1400 mistake.

[Firebirdjones]

Originally Posted by BRUISER

You guys are talking me out of a Bowtie Overdrive 700R4. I know I'm going to flog it regularly and add spray at some point, I don't need a $1400 mistake.

It's not as bad as these people make it out to be. Granted there are weak areas in the 700/4L60, they can all be addressed and handle more power than the average person here will throw at it. Several in this area I know of in 4th gens that run bottom 10's and make well over 700 HP and live just fine. It's not a cheap 4L60 however, you are talking $2000-$2500 or more to build it. One builder in particular that I've dealt with will dare you to break it.
Spending that kind of dough, you have to ask the question, would another trans be better suited for that kind of abuse to start with? For a driver and even mild performance or mild towing, no worries with a 700.

However, as I mentioned, for my intended purposes as a work horse overdrive setup that will see over 500 ft lbs. continuously in my 1 ton pulling 16,000 lbs, my choice was the 400 turbo with a gear vendor, as I gained more advantages that even a 4L80 couldn't provide.

[cal30_sniper]

Exactly. I just can't understand what the 4L80e gives people that the TH400/GV doesn't, other than the ability to custom tune every shift point. As for myself, I've never felt like I was in a situation that a well done shift kit wasn't handling perfectly well. If you feel the need to personally control every single gear shift, why not just swap in a manual and get the added efficiency bonus? Otherwise, why not take the great simplicity of the TH400 and gear vendors over the complicated electronics of the 4L80?

[Firebirdjones]

Originally Posted by cal30_sniper

Exactly. I just can't understand what the 4L80e gives people that the TH400/GV doesn't, other than the ability to custom tune every shift point. As for myself, I've never felt like I was in a situation that a well done shift kit wasn't handling perfectly well. If you feel the need to personally control every single gear shift, why not just swap in a manual and get the added efficiency bonus? Otherwise, why not take the great simplicity of the TH400 and gear vendors over the complicated electronics of the 4L80?

I think we're on the same page, I agree completely. I also like the idea of a manual, and run a T56 in my wifes car, she loves it.

If a manual were easily doable in my truck, I wouldn't mind going that route, but since it's factory equipped with a 400th the gear vendor made an obvious choice for me. It was just too easy.

[Chevyman350]

Originally Posted by cal30_sniper

Exactly. I just can't understand what the 4L80e gives people that the TH400/GV doesn't, other than the ability to custom tune every shift point. As for myself, I've never felt like I was in a situation that a well done shift kit wasn't handling perfectly well. If you feel the need to personally control every single gear shift, why not just swap in a manual and get the added efficiency bonus? Otherwise, why not take the great simplicity of the TH400 and gear vendors over the complicated electronics of the 4L80?

one advantage is locked torque converter for trans temps and power transfer. If your diesel this is a big plus.

You are correct for a heavy application both are great canadates it boils down to prefrence and which plusses you want, the ones from the 80 or the ones from the th400/GV.

But back to the economics as stated before assume on the lowest end of the % fuel mileage increase do to the factors stated (size "aero", weight, engine load etc.) and use that to give you an estimate of when it "could" pay for itself.

[BigBlocksRule]

A $300 4L80E core plus overhaul plus what it takes to run it is still cheaper than the GV.

[68Timber]

Originally Posted by Firebirdjones

It's not as bad as these people make it out to be. Granted there are weak areas in the 700/4L60, they can all be addressed and handle more power than the average person here will throw at it. Several in this area I know of in 4th gens that run bottom 10's and make well over 700 HP and live just fine. It's not a cheap 4L60 however, you are talking $2000-$2500 or more to build it. One builder in particular that I've dealt with will dare you to break it.
Spending that kind of dough, you have to ask the question, would another trans be better suited for that kind of abuse to start with? For a driver and even mild performance or mild towing, no worries with a 700.

However, as I mentioned, for my intended purposes as a work horse overdrive setup that will see over 500 ft lbs. continuously in my 1 ton pulling 16,000 lbs, my choice was the 400 turbo with a gear vendor, as I gained more advantages that even a 4L80 couldn't provide.

I should in the 440-460hp range on motor plus a 125 shot. I'll stick to the TH350.

[Firebirdjones]

Originally Posted by BRUISER

I should in the 440-460hp range on motor plus a 125 shot. I'll stick to the TH350.

That's really not much stronger, and would still have to be built stout to handle that kind of power. If you are that worried, I'd ditch the 350 and go 400.

We've always referred to the 700's as just glorified 350's. Biggest difference is the price.

[68Timber]

Originally Posted by Firebirdjones

That's really not much stronger, and would still have to be built stout to handle that kind of power. If you are that worried, I'd ditch the 350 and go 400.

We've always referred to the 700's as just glorified 350's. Biggest difference is the price.

I'd trust a TH350 anyday over a 700, I've had two of those fail in a stock application and never had a problem with a turbo 350. I've got a TH400 in my diesel truck ready to be swapped out, but I think I'll be fine with a built 350. No doubt a built 400 would be bulletproof but depending on who you believe, it also has 10 to 25 hp more parasitic loss over the 350.

[Firebirdjones]

Yep less HP to turn a 350 which is why I used one in the chevelle for a few years in the quest for quicker ET's. It would munch it just about every 2nd season and come out for another refresh. I did that twice so I eventually went back to the original 400 turbo, and the first one lasted 20 years I'm now on another refresh of the 400 that I did 6 years ago.