8l90

[DURAtotheMAX]

Well now that its confirmed for both the C7 Z06 Vette and 2015+ Silverado/Sierra pickup trucks.....I wonder what controller its using? Its externally mounted, so probably not related to the T43 in any way.

Sorry Ross, someone had to be the first jackass to ask about the new 8-speed controller!! :mrgreen: :chair:


Ben

[GMPX]

As far as I know it is an Aisin designed trans - TL-80SN (TCM is Aisin too), sorry but it probably won't be supported. :frown:

[Taz]

I believe the 8 speed is only being offered in 2015 trucks if you choose the L86 6.2L engine - won't be as many of these as there may have been, if it were to be offered with the L83 5.3L.

I'm pleased that the 6L80 is being offer with the 4.3L V6 as of 2014 - should make for great supply vs demand pricing in a few years at my local wrecking yard.

[DURAtotheMAX]

As far as I know it is an Aisin designed trans - TL-80SN (TCM is Aisin too), sorry but it probably won't be supported. :frown:

No, its 100% a GM clean-sheet in-house design.

http://www.thetruthaboutcars.com/2014/04/saturation-dive-the-gm-8l90-transmission/

I looked at the service manual and the drawing it shows of the TCM looks like it says T87 on it? Does T87 ring any bells?

[GMPX]

The only 8 speed stuff I have seen is for RPO MGG, so maybe what you have is something different. The 'MGG' trans is Aisin and the TCM is too, definitely not GM in house design. T87 means nothing to me but it sounds like GM are offering two 8 speed autos.
I also question why a 6.2L motor 'needs' 8 speeds, marketing departments need something to sell I suppose.
We have a Jeep Diesel with a ZF 8 speed and around town I don't think it ever gets above 6th and with 570 NM of torque from 2,000 RPM it could get away with a 4 speed around town, can't see the 6.2L motor being any different especially when they cruise at 1,100 RPM on the highway in 6th.

None of which changes the fact that we aren't currently working on them.

[RonC]

I found this searching for info on the new 8 speed;

"That new ‘8L90’ transmission, designed completely within GM, by a dedicated team, is a traditional hydraulic automatic—solenoids, valves, planetary gearsets and all—but GM says that it provides the super-quick shifts of dual-clutch boxes, yet with more smoothness.
The eight-speed automatic is actually quicker-shifting than the PDK gearbox in the Porsche 911, GM officials say; and that’s a transmission that engineers benchmarked for the project".

Corvette chief engineer Tadge Juechter pointed to some tough packaging challenges. There wasn't any existing dual-clutch gearbox that could take the torque of the engine and would fit in the space permitted.
“It's engineered by GM, internally, and many of the parameters were focused on this car,” said Tadge Juechter, at a pre-show event. “So it's almost a custom transmission.”

I would hope it also has a GM controller...

[GMPX]

<snip>
Go easy fellas, keep it on track.

[DURAtotheMAX]

The only 8 speed stuff I have seen is for RPO MGG, so maybe what you have is something different. The 'MGG' trans is Aisin and the TCM is too, definitely not GM in house design. T87 means nothing to me but it sounds like GM are offering two 8 speed autos.
I also question why a 6.2L motor 'needs' 8 speeds, marketing departments need something to sell I suppose.
We have a Jeep Diesel with a ZF 8 speed and around town I don't think it ever gets above 6th and with 570 NM of torque from 2,000 RPM it could get away with a 4 speed around town, can't see the 6.2L motor being any different especially when they cruise at 1,100 RPM on the highway in 6th.

None of which changes the fact that we aren't currently working on them.

Yeah the 8L90 is RPO code M5U. This is a heavy-duty trans exclusively for the trucks/SUV's, and the Corvette.

The 8-speed Aisin (MGG) is a completely different trans; its a smaller light-duty unit for the cars (CTS, etc).

I just looked up pinouts for both the 8L90 and the Aisin 8-speed. Connectors and pinouts are completely different. So the 8L90 definitely has a different TCM. Hopefully its something GM/Delphi-ish :)

Ben

[Taz]

Go easy fellas, keep it on track.

No problem here Ross, but you may want to look at the pattern of posts by slows10. In recent times he simply comes here to take shots at people, but posts nothing helpful himself.

Perhaps the Forum moderators could be proactive on this one.

Many of the "old crowd" doesn't post here anymore, perhaps as a result of these types of childish comments. Too bad, some of the people that use to participate had a great deal to offer.

In all of my posts, I have yet to ask for any help for anyone, I have always tried to help the decent folks who frequent this Forum, but draw the line at putting up with the abuse of the insolent or the arrogant.

No loss to me if I join the crowd of retirees - if fact, it would free up some of my time.

Nothing like biting the hand that feeds you ...

[DURAtotheMAX]

I did some more research on this...and it looks like the T87 is a Hitachi TCM, "running GM software".

FWIW........

Ben

[GMPX]

T87, it has a name finally ;) FWIW, the E37 was of course made by Hitachi too running GM software. I really don't know but I would guess the software for the 8 speed will be a clean sheet design from anything previous.