# 1996 Tahoe Conversion



## Tator (Dec 14, 2018)

Hello all!
I am new here to the forums, and am looking for some surface level help (at least, at the moment I am). I have a 1996 2-door Tahoe that is my pride and joy... except the mileage. On a good day i get about 13mpg city and doesnt really change with towing. With that mileage and a 30gal tank it leaves a sore spot in my pocket. 

I've been thinking about this, would it be possible to swap the current 4l60e transmission with a 2ml70 that is in the ~2008 tahoes? The 2ml70 contains seemingly everything I would need to mount and apply electric power to the drivetrain, and then I can handle finding and mounting the batteries. I would like to keep 4WD as well as the stock 5.7L Vortec. I'm just not sure how much of the wiring and datat would transfer over. Would the hybrid control unit that is in the 2008 series tahoes act independently from the ECM? Or at least have some common wires with my stock ECM and be able to emulate others? Possibly I could buy a aftermarket ECM that would have the wires needed for the ECM.

I have mechanic experience and have no fear of ripping anything out, its just choosing the right parts and compatibility that I'm not too sure with. I also have a general knowledge of electronics and ideas behind motors and their controllers.

I know this thing is heavy, and i'm not looking for massive increase in mpg, I just want a cool project that maybe will cost ~$5000 and bring me up into the low 20s at least. While still keeping the majority of the Tahoe stock (low priority, but its a cool truck as it is)

TLDR; Can I convert my 1996 5.7L with ~2008 tahoe hybrid parts?

Thanks guys! Appreciate any help/references that would help!


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## Synonym9 (Sep 15, 2017)

Electric Tahoe? Thats my thing.....a Squarebody would be even cooler.
Cannot wait for this to start


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## brian_ (Feb 7, 2017)

Synonym9 said:


> Electric Tahoe? Thats my thing.....a Squarebody would be even cooler.


Not an electric Tahoe... a hybrid Tahoe. I had a "Squarebody", and sent it to a scrapyard, which is definitely where it belonged... but some people do like them.


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## brian_ (Feb 7, 2017)

I have no idea how compatible the electronic systems are of these two different generations - and you have already identified that as the key issue - but at least physical mounting of the transmission should be practical.

I have no idea what the salvage value of a 2ML70 might be, but GM lost many thousands on dollars on each one of these vehicles that they sold, because the hybrid system was so expensive. Keep in mind that you need all of the associated electronics - the controller/inverters are external to the transmission.

For a trailer tow vehicle, I would be more interested in the entire GMT900 hybrid Tahoe... with the 6.0 LFA/Z1 engine that it is supposed to have, or even better a later generation engine. One reason that GM dropped the hybrids was that with the newer Gen V engines and 8-speed transmissions they improved fuel economy to the point that the hybrids (with their Gen IV engines) were not justified.


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## rmay635703 (Oct 23, 2008)

https://www.cars.com/vehicledetail/detail/759431374/overview/

Or you could just spend $9995 and have a working example you can tinker on while driving?


That particular 2 mode hybrid was the progenitor of the Volt and far as I can tell was usually in a 2wd Tahoe or a couple 2wd Pickups.


To be honest you could get more bang for your buck with a manual transmission conversion or even a 4.3/5.7 or 6.2 c-code diesel (with said MT) to get better economy.

A couple folks have dumped a FWD Hybrid car platform under a truck body, 
my guess is the same technique would work with a Volt if you want a more powerful plug in.


In so far as a pure Bev only a junk bolt drivetrain/battery would be adequate for a driving brick and even then you may only have an 80 mile range.

Ah well
good luck


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## Synonym9 (Sep 15, 2017)

Squarebody belongs to the scrapyard???
SOME people like them???

BOY, what did I turn myself into here???


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## brian_ (Feb 7, 2017)

rmay635703 said:


> That particular 2 mode hybrid was the progenitor of the Volt and far as I can tell was usually in a 2wd Tahoe or a couple 2wd Pickups.
> ...
> A couple folks have dumped a FWD Hybrid car platform under a truck body,
> my guess is the same technique would work with a Volt if you want a more powerful plug in.


While the 2ML70 was an early GM multi-mode power-split hybrid transmission, and the Volt's transaxles (two different generations) are also of that general type, that's where the similarity ends. The Volt hardware is great for a compact plug-in hybrid car, but would not be very useful in a Tahoe. Two of them (one per axle) might be adequate (with a massive amount of work), but the Two-Mode system designed for the truck would be a much easier fit.

The Two-Mode hybrid was available across the GM light truck range (1500 level), including both the SUVs and both brands (Chevrolet Silverado and GMC Sierra) of pickup. It's rare to see a 2WD pickup or SUV here, and I don't think the hybrids were any exception. The 2ML70 is designed as a bolt-in replacement for the conventional automatic transmissions (I don't think there was a manual in the GMT900 generation), so the 4WD system is the same for hybrid and conventional variants.

The hybrid GMT900 series was never offered as a plug-in hybrid. It could be done, of course, if you can find enough space for battery, if you can tolerate the loss of payload, and if you can handle the battery management complications of using something other than the OEM hybrid battery.


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## brian_ (Feb 7, 2017)

Synonym9 said:


> Squarebody belongs to the scrapyard???
> SOME people like them???


Mine belonged in a scrapyard; I assume yours is very nice.  I don't think it's the most popular generation of GM pickup truck - and it may be my least favourite - but fortunately different people have different preferences. Personally, I like the styling of the first-generation Silverado and other GMT 400-series models best (which includes Tator's Tahoe).


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## rmay635703 (Oct 23, 2008)

brian_ said:


> While the 2ML70 was an early GM
> . It's rare to see a 2WD pickup or SUV here, and I don't think the hybrids were any exception. The 2ML70 is designed as a bolt-in replacement for the conventional automatic transmissions (I don't think there was a manual in the GMT900 generation), so the 4WD system is the same for hybrid and conventional variants.


Ive never seen a 4wd hybrid Tahoe for sale so I took a look nationwide and it appears to be a 50/50 mix of RWD and 4 wheelers (at least for sale)

My guess being a California special alters the drivetrain mix.


Personally I prefer RWD manual transmission diesel Suburbans with bench seats for work activities and ditto trucks, would love to see a 50/50 mix like that.
The maintenance and fuel economy benefits exceed any winter traction benefit , too bad people forgot how to drive RWD vehicles 

Ah well


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## brian_ (Feb 7, 2017)

rmay635703 said:


> Ive never seen a 4wd hybrid Tahoe for sale so I took a look nationwide and it appears to be a 50/50 mix of RWD and 4 wheelers (at least for sale)
> 
> My guess being a California special alters the drivetrain mix.
> 
> ...


Popularity of *4WD* is certainly regional. While I've never owned a 4WD/AWD vehicle, and I live in a rural area in a region where winter is half of the year, I don't question the appropriateness of 4WD/AWD for others... especially for front-heavy pickups in which the 2WD alternative is rear wheel drive. Personally, I can't image owning a truck-based SUV with only 2WD - it seems like a lot of weight and bulk without the expected capability - but I don't live in California. In contrast, my motorhome has about 60% of its weight on the rear axle, so 2WD is fine and 4WD would be relatively pointless. I don't know how Tator uses, or intends to use, his Tahoe.

*Manual transmissions* are inherently a bit more efficient, but three factors argue in favour of conventional automatics for both performance and fuel economy:

lock-up torque converters eliminate most of the efficiency difference,
more ratios can be practically used in an automatic (manuals for light vehicles effectively max out a six speeds, and automatics are currently at 10 speeds), and
most drivers don't shift at appropriate points.
Power-split hybrid transmissions such as the 2ML70, Volt, and Toyota Synergy hybrids are automatic, so there's no choice in that case. Even in parallel hybrids, getting the driver to effectively work as part of the powertrain management system is largely futile. For most modern vehicles there is no choice offered - while a manual was available for a Tahoe or pickup of Tator's era, I don't think a manual has been offered for any of these vehicles in this century.


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