T-56 swap, no cruise in 6th
09-13-2007, 02:58 PM
#12
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Ok , here are the tune for my 06 silverado and I think an 05 SSR 6 spd. I have an SSr trans. in my truck (slightly different gear ratios than the m6). I am going to check my tire roll out in a few minutes .
Thanks
Ron
Thanks
Ron
10-31-2007, 10:33 AM
#13
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just a wild thought but can you get a copy of an 07 (i think) with the 6-speed auto and combine that with our computers to get the computer to see 6 gears?
03-03-2013, 06:04 PM
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No Cruise in 6th ?
A dude who installed the 40 tooth Automatic Speedo Gear in his T56 said it fixed the problem. I have the gear but after swapping out a good LS1 for a good LS2 / 402 ci. Have had no time to change out the gear. Tho going to have to do this quick as I have a road trip back to Kansas in June.. Don't know if an SSR tune would work or not ?
The 402 is so nice chugging around in 5th or 6th.
The 402 is so nice chugging around in 5th or 6th.
03-17-2013, 07:39 AM
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Finally installed the 40 tooth gear in the T56 yesterday.
Edited my tune to reflect the 40 teeth.
Drove it and still no cruise in 6th.
No change with 40 tooth gear. Changed axle ratio in tune to 4.56 = no change.
I don't think there is any switch or sensor that tells the ECM/TAC what gear the trans is in ?
On the old 5 spd trans, there was only the rev light switch and speedo connection. T56 I added the rev lockout powered by brake lights.
Edited my tune to reflect the 40 teeth.
Drove it and still no cruise in 6th.
No change with 40 tooth gear. Changed axle ratio in tune to 4.56 = no change.
I don't think there is any switch or sensor that tells the ECM/TAC what gear the trans is in ?
On the old 5 spd trans, there was only the rev light switch and speedo connection. T56 I added the rev lockout powered by brake lights.
Last edited by silverado2003; 03-17-2013 at 09:41 AM. Reason: .
03-17-2013, 01:42 PM
#20
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The only way the computer can know what gear the trans is in is by comparing RPM to VSS. I believe the computer is not engaging cruise because it sees that t-56 6th is outside the ratio of the original trans.
I think your original trans is an NV3500 that had a 5th gear of 0.73:1. 6th in your new T-56 is 0.50:1. You should be able to fool your computer into thinking the T-56 6th is 0.73:1 by adjusting the VSS pulses the computer is expecting. 0.5/0.73*40 = 27.4 so set VSS pulses in your computer to 27.
I think changing to a 40 tooth reluctor worked for the other guy because he never changed his VSS count in his computer to compensate like you did.
Your speedo will be fast and your ABS light will come on but if my theory is correct cruise should now work. Speedo and ABS both have their own output multipliers to fix those issues elsewhere. Try this and please let us know if it works.
Mike
I think your original trans is an NV3500 that had a 5th gear of 0.73:1. 6th in your new T-56 is 0.50:1. You should be able to fool your computer into thinking the T-56 6th is 0.73:1 by adjusting the VSS pulses the computer is expecting. 0.5/0.73*40 = 27.4 so set VSS pulses in your computer to 27.
I think changing to a 40 tooth reluctor worked for the other guy because he never changed his VSS count in his computer to compensate like you did.
Your speedo will be fast and your ABS light will come on but if my theory is correct cruise should now work. Speedo and ABS both have their own output multipliers to fix those issues elsewhere. Try this and please let us know if it works.
Mike
Last edited by mikesz; 03-17-2013 at 01:56 PM. Reason: Had the vss multipler backwards...