Does anyone know anything about the 6t80 Cadillac XTS transmission, I can't even find a picture of it, all I found was a small mention of its ratings on Wikipedia and that it's built on the same platform as the 6t70 and 6t75, definitely worth looking into for a v8 build, all I can find is that's it'd being coupled with the twin turbo v6
It's basically the same as the 6t70/75, but with some stronger components. It will also have the High Feature bell housing pattern that the High Feature DOHC V6 engines use. Archie's adapter plate is made for metric bell pattern transmissions, and not the HF bell pattern. It should be possible to make a custom adapter plate for the newer bell pattern though, if you wish.
While the 6t80 is rated for the higher output engine, the LF3 still only makes 369 lbs-ft of torque, so you may likely still need to get a performance build done on it, to be able to support the 570 lbs-ft you were claiming would need to be supported in your other thread. A performance build of the 6t80 might end up with the same specs for max torque that a built 6t75 would take. I'd get in contact with a couple of the shops that do performance builds of the 6t transmissions, and see what they offer for both, and what the cost difference would be.
I read the thread on the ls4 with the pcs controller for the transmission and how the biggest issue wasn't torque per say but the torque management, and the transmission was still holding up, and if torque management was the biggest issue, the 6t70 and 75, I've also been doing some more research and I've found that the xts actually uses the 6t70 for the fwd version and the 6t80 is actually the awd version, from what I have found, which is why I'm not able to find much on it but if the 6t70 is holding up to that twin turbo, it should be able to hold up to the v8 with proper torque management
I read the thread on the ls4 with the pcs controller for the transmission and how the biggest issue wasn't torque per say but the torque management, and the transmission was still holding up, and if torque management was the biggest issue, the 6t70 and 75, I've also been doing some more research and I've found that the xts actually uses the 6t70 for the fwd version and the 6t80 is actually the awd version, from what I have found, which is why I'm not able to find much on it but if the 6t70 is holding up to that twin turbo, it should be able to hold up to the v8 with proper torque management
From what I can see, the engine/trans pairings are as such:
LTG - 6t70 LFX - 6t75 LF3 - 6t80
The LFX is available in AWD or FWD. The LF3 is only avaialble with AWD. The LTG is not available in the US. The comparison page on the Cadillac web site also doesn't list the 3.16 axle ratio as available for the Premium model, which has AWD as an option, but only the 2.77 ratio, so I think the only difference in the transmissions between AWD and FWD, is that the AWD transmissions have the extra output housing added, to support a driveshaft for the rear wheels.
I expect even the 6t80 won't hold up to full abuse from the LF3 engine, with torque management fully disabled. The factory programming for the torque management tends to be conservative though, to protect the transmissions. A built trans with the torque management pulled back a bit, or all the way out, should be able to handle the power though.
Lol, Ive Googled the 6t80 and can find hardly anything, though probably the 6t75 is sufficient once built, I found some companies that rebuild them but haven't found much as far as making them much stronger
How does the AWD work with the 6T80 transaxle? Is the transaxle mounted longitudinal rather than transverse, where outputs and half shafts become drive shafts to the differentials?
quote
Originally posted by dobey:
From what I can see, the engine/trans pairings are as such:
LTG - 6t70 LFX - 6t75 LF3 - 6t80
The LFX is available in AWD or FWD. The LF3 is only avaialble with AWD. The LTG is not available in the US. The comparison page on the Cadillac web site also doesn't list the 3.16 axle ratio as available for the Premium model, which has AWD as an option, but only the 2.77 ratio, so I think the only difference in the transmissions between AWD and FWD, is that the AWD transmissions have the extra output housing added, to support a driveshaft for the rear wheels.
I expect even the 6t80 won't hold up to full abuse from the LF3 engine, with torque management fully disabled. The factory programming for the torque management tends to be conservative though, to protect the transmissions. A built trans with the torque management pulled back a bit, or all the way out, should be able to handle the power though.
[This message has been edited by Civil (edited 11-02-2021).]
If someone is looking to do an LF3 swap with the 6T80 transmission, it sounds great . but it won't fit in the available space in the Fiero engine compartment. The trans is large, heavy and the engine with twin turbos takes up a lot of space.
------------------ " THE BLACK PARALYZER" -87GT 3800SC Series III engine, custom ZZP /Frozen Boost Intercooler setup, 3.4" Pulley, Northstar TB, LS1 MAF, 3" Spintech/Hedman Exhaust, P-log Manifold, Autolite 104's, MSD wires, Custom CAI, 4T65eHD w. custom axles, Champion Radiator, S10 Brake Booster, HP Tuners VCM Suite. "THE COLUSSUS" 87GT - ALL OUT 3.4L Turbocharged engine, Garrett Hybrid Turbo, MSD ign., modified TH125H " ON THE LOOSE WITHOUT THE JUICE "
Fitment is not an issue for my build. I am curious of how the AWD works with the transaxle. Isn't this a transverse transaxle? So how does the transaxle shafts connect to the front and rear wheels?
quote
Originally posted by Dennis LaGrua:
If someone is looking to do an LF3 swap with the 6T80 transmission, it sounds great . but it won't fit in the available space in the Fiero engine compartment. The trans is large, heavy and the engine with twin turbos takes up a lot of space.
Fitment is not an issue for my build. I am curious of how the AWD works with the transaxle. Isn't this a transverse transaxle? So how does the transaxle shafts connect to the front and rear wheels?
The transmission has an external differential on the output shaft of the transmission, passenger side. This differential sends a drive shaft to the rear wheels (in the case of the Fiero that would be your rear bumper). All wheel drive in a Fiero is a bit more tricky than a front wheel drive. The extra differential regulates differences in front wheel speed vrs rear wheel speed. This is needed to prevent scuffing. An all wheel drive car requires 3 differentials. In the transverse transmission two of the differentials are on the transmission. It is large. But this same type of all wheel drive system is also in F40 6 speed manuals as well in the Saab and other applications.
[This message has been edited by Rickady88GT (edited 11-02-2021).]
Is the differential / transfer case only for the 6T80? If not, are they rated the same, or is the 6T80 differential / transfer case rated higher?
quote
Originally posted by Rickady88GT:
The transmission has an external differential on the output shaft of the transmission, passenger side. This differential sends a drive shaft to the rear wheels (in the case of the Fiero that would be your rear bumper). All wheel drive in a Fiero is a bit more tricky than a front wheel drive. The extra differential regulates differences in front wheel speed vrs rear wheel speed. This is needed to prevent scuffing. An all wheel drive car requires 3 differentials. In the transverse transmission two of the differentials are on the transmission. It is large. But this same type of all wheel drive system is also in F40 6 speed manuals as well in the Saab and other applications.
[This message has been edited by Civil (edited 11-02-2021).]
think of your normal FWD trans except that one side has a kind of "T" where the drive axle is connected to a 90 deg output. The drivers side is normal, coming out of the FWD trans and on the other side, where the "half shaft" would be the front/rear diff is bolted on. The pass side axle attaches to the diff and then the rear is "T" off of it headed to the back of the car just like a RWD would do.
