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Discussion Starter #1
We have seen stock transmissions start to have an issue at stock power levels with long term driving on them, let alone at higher power levels then stock. So we have come up with the ultimate upgrade to the stock 5 speed transmission. This T56 conversion swaps in a 6 speed T56 transmission from a Pontiac GTO with a LS2 V8 into the Pontiac Solstice or Saturn Sky.

This conversion can be completed on either an automatic car to convert it to a manual, or as a straight upgrade from the stock 5 speed. Also available as an option is to have your stock driveshaft modified, or a new lightweight aluminum driveshaft for the conversion. The base kit includes the following parts -

New GM Clutch Master Cylinder
New GM Clutch Slave Cylinder
New GM Pilot bearing
Slave Cylinder spacer
New GM flywheel bolts
New DDMworks lightweight flywheel
New DDMworks Clutch kit
New DDMworks custom bellhousing adapter
New VSS plug
New backup swithc
New T56 shifter adapter
New T56 shift ball
New DDMworks Custom T56 backbone 1/2" thick
All new associated hardware needed for install

This is everything needed to convert your car from the stock 5 speed to the much stronger T56 6 speed transmission found on our V8 swaps into the Solstice/Sky. You can choose to source your own transmission from a 2006 or newer Pontiac GTO, or purchase a new one as an option listed above and have everything delivered together. We also offer this as a conversion service here at the shop, please email or contact us for current price of installation.

If converting an automatic car, you will also need a new clutch pedal and brake pedal and a few other components. Please contact us and we can get you the additional parts needed.

The install kit starts at $3150 and goes up from there depending on what options you pick.

Installation is about the same as doing a clutch swap on the car, if converting a manual car, obviously an automatic takes a little bit more with doing the pedals and some other wiring needs to be done.

Link to the product page on our site - T56 Conversion for Solstice/Sky

We have done some of these conversions, here are some pictures from the installs:



This is a picture of the custom backbone that comes with the install kit. It is 1/2" thick and unique for this conversion, although very similar to the one used on the V8 swaps we do.



Picture of the custom bell housing adapter being fit to the engine first, then the transmission gets bolted to it in place

Please let me know if you have any other questions I can answer for you.

Thanks,
Dave
 

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Looks fantastic Dave.

This will be my next big project. Auto 5 speed to T56. Will have to do major sucking up for this one as I have just spent big $$ on wheels and tires. I want a 6 speed standard sooooooo bad. Really glad you are offering the conversion.
 

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I love the idea but $6980 for parts then you still have to add tax, shipping, and installation. That is probably just over $8000 total. I have always wondered why this car only came with a 5 speed stick truck transmission when other cheaper performance cars had 6 speed getrags or tremecs, I guess that $8000 pricetag answers my question maybe.

Has full testing been done on this? Like what kind of increase should we expect in 0-60mph and 0-100mph? what about increases in MPG?
 

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If it's similar to mine, With the stock GXP rear end it gets into fifth at 45 to 50 so you get a significantly quicker low end but in sixth it's turning very low RPMs at freeway speeds. It takes a little getting used to, but it works well.
 

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Discussion Starter #6
Is the aluminum drive shaft compatible with the factory transmission? If possible what are the weight savings?
We can do a custom aluminum driveshaft for the stock transmission, but the one for the T56 swap will not drop right into the stock transmission, they are different lengths, so I do not have a direct weight comparison of a stock length steel vs aluminum driveshaft.
 

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Discussion Starter #7 (Edited)
I love the idea but $6980 for parts then you still have to add tax, shipping, and installation. That is probably just over $8000 total. I have always wondered why this car only came with a 5 speed stick truck transmission when other cheaper performance cars had 6 speed getrags or tremecs, I guess that $8000 pricetag answers my question maybe.

Has full testing been done on this? Like what kind of increase should we expect in 0-60mph and 0-100mph? what about increases in MPG?
Here is a graph comparison between the torque at the wheels and shift points for the T56 vs stock 5 speed both with the same 3.7 rear end with a 7200rpm cutoff.



The T56 makes less torque at the wheels in 1st gear (not a bad thing since the people that have done this are making more then enough power to spin the wheels in first) but can hold the gear out much longer (52mph vs. 41mph). 2nd gear the power gets closer to the same with the T56 able to go out to 75mph, third gear goes to 109, fourth to 154. The 6th gear makes a great cruiser as it is theoretically capable of 272mph if you had the power to push that far.
 

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Here is a graph comparison between the torque at the wheels and shift points for the T56 vs stock 5 speed both with the same 3.7 rear end with a 7200rpm cutoff.



The T56 makes less torque at the wheels in 1st gear (not a bad thing since the people that have done this are making more then enough power to spin the wheels in first) but can hold the gear out much longer (52mph vs. 41mph). 2nd gear the power gets closer to the same with the T56 able to go out to 75mph, third gear goes to 109, fourth to 154. The 6th gear makes a great cruiser as it is theoretically capable of 272mph if you had the power to push that far.

these numbers are with the ecotec motors or V8?
 

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Here is a graph comparison between the torque at the wheels and shift points for the T56 vs stock 5 speed both with the same 3.7 rear end with a 7200rpm cutoff.



The T56 makes less torque at the wheels in 1st gear (not a bad thing since the people that have done this are making more then enough power to spin the wheels in first) but can hold the gear out much longer (52mph vs. 41mph). 2nd gear the power gets closer to the same with the T56 able to go out to 75mph, third gear goes to 109, fourth to 154. The 6th gear makes a great cruiser as it is theoretically capable of 272mph if you had the power to push that far.
Can you re-graph with the 3.91 ring and pinion and the T-56 vs Aisin with 3.73?
 

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Discussion Starter #11
What's the weight penalty?
The stock 5 speed weighs - 118#
The T56 weighs - 128#
The stock auto weighs - 156#

from there it gets a little tricky because we use a lightweight flywheel with the swap, which is lighter then the dual mass setup on the GXP and lighter then the stock 2.4L also. The backbone we are using is heavier then stock, but if you already have a backbone, then there would be no additional weight penalty.

In general on an automatic car you should drop around 30-40 pounds, on a manual car it will be pretty close to a wash if you had a stock flywheel and backbone already.
 

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I love the idea but $6980 for parts then you still have to add tax, shipping, and installation. That is probably just over $8000 total.
Ditto. Don't get me wrong, conversions idea is totally t*ts but the price :willy:
 

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Interim stop on the way to a V8.......:willy:
 

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Stage 3 on the way......baby steps....one of these days I'm going to take man:devil: steps...when my wife lets me :lol:
 
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