6speed 6T45 FWD Trans Conversion?
06-08-2010, 12:06 PM
#41
Launching!
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I don't know. The best I can answer that is that anything that the DIC/BCM/IP reads from the ECM will be unaffected. But if it needs any data from the TCM...????.
06-08-2010, 12:06 PM
#42
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Yeah, I've felt the third gear woes as well. 
Good thing the other guy gave up and turned down another street.
[scratched up record]
The 6 speed (6T75) would be our "cure" (G8 transmissions for comparison):
Transmission: 6T75 | 4T65E-HD | 6L80 | TR-6060
Gear ratios:
First: 4.484 | 2.92 | 4.027 | 2.66
Second: 2.872 | 1.56 | 2.364 | 1.78
Third: 1.842 | 1 | 1.532 | 1.30
Fourth: 1.414 | 0.7 | 1.152 | 1.00
Fifth: 1 | N/A | 0.852 | 0.79
Sixth: 0.742 | N/A | 0.667 | 0.63
Reverse: 2.882 | 2.38 | 3.064 | 2.90
Final drive ratio:
3.16 | 2.93 (GXP, Super)/3.05 (CX, CXL)/3.29 (SS) | 3.27 (G8 GXP) | 3.70 (G8 GXP)
[/scratched up record]
We wouldn't feel the third gear woes until we hit fifth! That gives us third and fourth to play with.
Good thing the other guy gave up and turned down another street.[scratched up record]
The 6 speed (6T75) would be our "cure" (G8 transmissions for comparison):
Transmission: 6T75 | 4T65E-HD | 6L80 | TR-6060
Gear ratios:
First: 4.484 | 2.92 | 4.027 | 2.66
Second: 2.872 | 1.56 | 2.364 | 1.78
Third: 1.842 | 1 | 1.532 | 1.30
Fourth: 1.414 | 0.7 | 1.152 | 1.00
Fifth: 1 | N/A | 0.852 | 0.79
Sixth: 0.742 | N/A | 0.667 | 0.63
Reverse: 2.882 | 2.38 | 3.064 | 2.90
Final drive ratio:
3.16 | 2.93 (GXP, Super)/3.05 (CX, CXL)/3.29 (SS) | 3.27 (G8 GXP) | 3.70 (G8 GXP)
[/scratched up record]
We wouldn't feel the third gear woes until we hit fifth! That gives us third and fourth to play with.
SPECIFICATIONS: HYDRA-MATIC 6T75 (MY9) | 4T65E-HD (M15/MD7/MN7)
Acadia/Enclave/Outlook/Traverse | GXP/SS/Super
Engine range:
3.6L - 4.6L | 2.5L - 5.3L
Maximum engine torque:
301 lb-ft (406 Nm) | 280 lb-ft (380 Nm)
Maximum gearbox torque:
380 lb-ft (515Nm) all gears | 400 lb-ft (542 Nm)
Gear ratios:
First: 4.484 | 2.92
Second: 2.872 | 1.56
Third: 1.842 | 1
Fourth: 1.414 | 0.7
Fifth: 1 | N/A
Sixth: 0.742 | N/A
Reverse: 2.882 | 2.38
Final drive ratio:
3.16 | 2.93 (GXP, Super)/3.05 (CX, CXL)/3.29 (SS)
Maximum shift speed/Maximum input speed:
Rev 5000 rpm | N/A
1-2 7000 rpm | 1-2 7000 rpm
2-3 7000 rpm | 2-3 6500 rpm
3-4 7000 rpm | 3-4 6000 rpm
4-5 6500 rpm | N/A
5-6 5798 rpm | N/A
Maximum validated gross vehicle weight:
2930 kg (6460 lbs) | 2903 kg (6400 lb)
Shifter Positions:
P, R, N, D, M, (DSC+/-) & L (MU/MD) | P, R, N, OD, 3, 2, 1/P, R, N, D & DSC +/-
Acadia/Enclave/Outlook/Traverse | GXP/SS/Super
Engine range:
3.6L - 4.6L | 2.5L - 5.3L
Maximum engine torque:
301 lb-ft (406 Nm) | 280 lb-ft (380 Nm)
Maximum gearbox torque:
380 lb-ft (515Nm) all gears | 400 lb-ft (542 Nm)
Gear ratios:
First: 4.484 | 2.92
Second: 2.872 | 1.56
Third: 1.842 | 1
Fourth: 1.414 | 0.7
Fifth: 1 | N/A
Sixth: 0.742 | N/A
Reverse: 2.882 | 2.38
Final drive ratio:
3.16 | 2.93 (GXP, Super)/3.05 (CX, CXL)/3.29 (SS)
Maximum shift speed/Maximum input speed:
Rev 5000 rpm | N/A
1-2 7000 rpm | 1-2 7000 rpm
2-3 7000 rpm | 2-3 6500 rpm
3-4 7000 rpm | 3-4 6000 rpm
4-5 6500 rpm | N/A
5-6 5798 rpm | N/A
Maximum validated gross vehicle weight:
2930 kg (6460 lbs) | 2903 kg (6400 lb)
Shifter Positions:
P, R, N, D, M, (DSC+/-) & L (MU/MD) | P, R, N, OD, 3, 2, 1/P, R, N, D & DSC +/-
Look carefully. 2nd gear on the 6T75 is lower than our 1st gear. So if anything, it'd be better should someone choose to start in 2nd.
The transmission should be fine for everyday driving. 1st gear included. "Racing" would be where some clever gear changes would be required. I'm not sure about everyone else, but I use TAPshift all the time.
Last edited by GXP25; 06-08-2010 at 01:34 PM. Reason: Final Drive Ratio mistake.
06-08-2010, 12:20 PM
#44
Where did you get that transmission info? I believe the GXP has the 3.29 final drive and the SS and Super have 3.06/3.05... (Or maybe I misreading your post)
I think the 2.77 final drive would be better than the 3.16 for all around driveability... As discussed on the previous page.
Yeah I would not view that as a big worry.
I think the 2.77 final drive would be better than the 3.16 for all around driveability... As discussed on the previous page.
Yeah I would not view that as a big worry.
06-08-2010, 01:32 PM
#45
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Where did you get that transmission info? I believe the GXP has the 3.29 final drive and the SS and Super have 3.06/3.05... (Or maybe I misreading your post)
I think the 2.77 final drive would be better than the 3.16 for all around driveability... As discussed on the previous page.
I think the 2.77 final drive would be better than the 3.16 for all around driveability... As discussed on the previous page.
My post and quote is wrong and will be updated.
That 2.77 final drive ratio is probably for the 6T70. The 6T75 only comes with a 3.16 final drive ratio.
I got my information from GM. I'll upload the documents again.
EDIT: Some old literature: https://ls1tech.com/forums/ls4-front...le-ratios.html
Last edited by GXP25; 06-08-2010 at 01:35 PM. Reason: Added a link.
06-08-2010, 02:08 PM
#46
Why is it that the Chevy cars seem to get better MPGs than the Pontiacs then? Hmmm... Quite strange.
I have read so much conflicting information on the internet, I don't know what to believe...
Either way on the 6 speed the 3.16 final drive is going to make first gear a smoke show.
I will read through the docs, thanks.
I have read so much conflicting information on the internet, I don't know what to believe...
Either way on the 6 speed the 3.16 final drive is going to make first gear a smoke show.
I will read through the docs, thanks.
Last edited by EmersonHart13; 06-08-2010 at 02:19 PM.
06-08-2010, 02:35 PM
#47
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GXP's have 3.29 as do the Chevys. We have sprockets, and a chain the drops the ratio to an effective gear of 2.93's. The GXP's have a taller tire I believe. Good way for GM to reduce power output to the wheels if you think about it.
06-12-2010, 01:05 PM
#48
Launching!
Thread Starter
Tried like hell to finish it up Friday, but just when we thought we were in the clear, trans fluid started gushing out of the electrical harness! So we called it a day and will see where we are at Monday.
07-21-2011, 05:18 AM
#54
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Seems that way. As long as we're on the subject of conversions that always seem to fall through, anybody seen a late model W-body RWD conversion? I'd love to have a LS2/T-56 combo
Maybe I'll try it one day when the car starts falling apart. 
07-21-2011, 10:03 AM
#56
10-20-2011, 03:35 PM
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I believe I can solve the computer problem, albeit only with the 6T70 based on information I have now. The good news though is that I believe the harder internals from the 6T75 can be swapped into the 6T70's case.
See my post below. This thread and the one below have gotten tantalizingly close to a solution to the LS4 question on the hardware side. I hope someone revives it, because I think I can solve the electronics side!
https://ls1tech.com/forums/ls4-perfo...l#post15530115
See my post below. This thread and the one below have gotten tantalizingly close to a solution to the LS4 question on the hardware side. I hope someone revives it, because I think I can solve the electronics side!
https://ls1tech.com/forums/ls4-perfo...l#post15530115
