6L90 option for G8- fitting for...for next trans failure

[gr8lover]

Going to do a test fit and check for a 6L90 in my G8 tomorrow. Have it all ready to go--- trans out......... 6L90 TCH/Case/extension all set to be fitted...

It appears to me that there is no issue fitting it into the car (minus the obvious Driveshaft shortening required, trans mount modifications, end of driveshaft..)

I think all I need to do is the following to make it work:

Shorten driveshaft or make new-- with new new end
modifiy mount-- will size up-- buy new mount and then modify to work-- not that bad...
replace 6L90 Valvebody TEHCM with the original g8 TEHCM
upgrade 6L90E with aftermarket clutches


The body of the case is slightly taller by maybe a 1/8" (and a slightly different slope) and the length is longer on 6L90.... everything else is same..... Torque converter housing is identical! Mounting is identical in front, Manual shaft is in exactly same positon and location, connections same location (easy fit)...

once I get mount figured out, this is my plan for after the rebuild goes.... I think a aftermarket 6L90 is the answer for many of us.... it is much stronger stock than the 6L80 and more opportunities for better aftermarket upgrades on it....

Included are some pics of the two cases (TCH is identical and is not included in pic



Dont look at extension on the 6L90 case.... i didnt put the extension on the 6L80 case so disregard relating to the difference.....

[norm8332]

Nice, How much power are you planning on putting through it?

[parish8]

hmm, didn't know there was any diference in the case.

i like where you are going with this. looks like an easy swap to me.

what does a 6l90e come in?

[bbradyc5]

hmm, didn't know there was any diference in the case.

i like where you are going with this. looks like an easy swap to me.

what does a 6l90e come in?

Think it comes in the CTS-V and STS-V cars .... not sure what else though....maybe some HD trucks

[vic2186]

What happend to your circle d tranny??

[1stGXPmaggie2.3]

gr8lover, do the 6l90 transmissions have more clutches or are they larger clutches. What aftermarket parts are you aware of that better the 6l90. If so then sounds like a great mod upgrade.

[gr8lover]

What happend to your circle d tranny??

The circle D tranny should arrive all upgraded tomorrow... I am excited about it but I guess I am looking for future options.. It was a good chance to check on this and figure it out now so if it happens again and have issues, I may just do the 6L90 upgrade with upgraded clutches and then I shouldnt ever have to worry about it... I guess I am still a bit worried on how much the upgrades will help. I am hoping for the best but looking for plans in the future.

[vic2186]

Cool bean!!keep us updated,,

[gr8lover]

gr8lover, do the 6l90 transmissions have more clutches or are they larger clutches. What aftermarket parts are you aware of that better the 6l90. If so then sounds like a great mod upgrade.

I dont have my cheat sheet with me now but the 6L90 has more clutch plates then the 6L80 and the opportunity for a much better clutch plate setup.... the 6L80 clutches surface area increased something like 50-75% with the upgrade, but the 6L90, already has significantly more and then more on top of that can be added.... also, the Output carrier is significantly larger with much larger pinions and sun gears, etc.., input carrier has 6 pinions vs 4(i upgraded this in my 6L80 already..) some of shafts are significantly larger..., case has more supports and ribbing for rigidity.... and there are things that not many people or "publications" see that make it a much stronger unit than the 6L80.... I will have to get a good list soon..... I seen some before but none of them include all the little things different....

[SinCity G8]

Thanks for being the first to try this. Is this the same tranny that is in the L99 Camaros?

[STL_G8GT]

Solid work, Chuck... I keep eyeballing a 1900... and I know that means tranny/rear diff parts... thank you for the pioneering here!!!!

FYI - still loving the cam. :-)

[gr8lover]

Nice, How much power are you planning on putting through it?

Not sure yet? but I hate to worry about stuff.... I would rather spend a bit more and have pc of mind... I hate this fixing stuff.. I like upgrading , but fixing in my opinoin stinks!!!! I will end up doing overdrive pulley on the supercharger, wider belt in the front and some pulley changes..., some new heads hopefully, and maybe meth or Nitrous.... but still undecided.... kind of watching and waiting I guess...

but I figure there are so many guys so good at all the other stuff, I figured I would try to concentrate on something I could maybe actually make a difference on and maybe help out on.....

[gr8lover]

Solid work, Chuck... I keep eyeballing a 1900... and I know that means tranny/rear diff parts... thank you for the pioneering here!!!!

FYI - still loving the cam. :-)

I am happy it is working out for you.... hopefully the new trans is still holding up for you!!!!!! :)

[Andy@SquashPerformance]

I'd still be worried about the tuning end of things. If you frag the Circle D 6l80 you're going to frag the 6l90, too...

Andy

[mi04se1]

Camaro uses 6L80 for all V8 autos. 6L90 only comes in 09+ CTS-v I believe.

[gr8lover]

Thanks for being the first to try this. Is this the same tranny that is in the L99 Camaros?

The 6L90 will be going in the new 2011 Z28 coming out in the near future.......I am not sure if they call it the L99 but last I heard it is very similar or identical to the CTS-V supercharged engine... sorry I dont know the engine info... just know we are getting ready for the 6L90 for the new Z28....

[gr8lover]

Didnt get a chance to try the 6L90 in yet- should be tomorrow. But I did get a chance to do a quick measurement on the two case Over-all-heights...I started from the case edge (where the case mates to the bell housing) and moved towards the tail.... see data below:

measurements are in mm and the "x" dim is referenced from case edge at Bell housing-to-case mating point moving toward output shaft end of trans.. The corresponding measurement is the "uppermost" point of the case relative to the Pan mounting surface...
"x" position 6L80 case-----------------------6L90 Case
at bell housing 297.1------------------------297.9
30mm 296.7------------------------297.5
100mm 271.4------------------------275.1
200mm 265.3------------------------272.1
300mm 260.3------------------------260.8
400mm 257.5------------------------258.3
418mm (for 6L80) 257.1 @end
453mm (for 6L90) -----------------------------256.53@end

I hope this makes sense but it shows the relative height of the case--- they are very close and I would think there is 7mm of clearance to the tunnel.....???...... I would hope... but a small hammer would work wonders if required.... will include pic to help explain a bit more later tonight...

[norm8332]

Looking forward to the test-fit.

[Eidolon]

I am not sure if they call it the L99 but last I heard it is very similar or identical to the CTS-V supercharged engine
The L99 is actually the DOD/AFM-enabled V8 in the automatic-equipped Camaro. It's the next-generation version of the L76 in the G8 GT. It's basically an AFM-enabled LS3, whereas the L76 is an AFM-enabled LS2. The manual-equipped Camaro uses the same LS3 stack as the G8 GXP, no AFM. (Rejoice, GXP owners, we'll be able to find all the engine parts we could ever need!)

The engine in the CTS-V is called the LSA, and is very similar to the 638-hp beast in the Corvette ZR1, the LS9. Both are based on the LS3 block, but are fitted with the Eaton roots-type supercharger. I'm not sure about exact differences between the two engines, such as whether or not the LSA gets the LS9's titanium connecting rods, etc., but Wikipedia points out that one difference is the supercharger applied: the ZR1's moves more air.

Wikipedia has a good summary of the 6.2L-engine family here: http://en.wikipedia.org/wiki/LS9#6.2_L

I believe the plan is for the Z28 to get the LSA rather than the LS9, so the Z28 would have around 550 HP. The LS9 would be a little on the pricey side for the Camaro Z28. Makes sense given what you've said, though. They'd basically be dropping the CTS-V's powertrain, tranny and all, into the Z28.

[G8-4-Speed]

Does it use the same TCM and connector? Is it a plug and play deal?

[mi04se1]

According to my parts catalog, the tcm is the same between a 6L80 G8 and a 6L90 CTS-v.

[gr8lover]

According to my parts catalog, the tcm is the same between a 6L80 G8 and a 6L90 CTS-v.

Tehcm and connector is exactly the same... the only reason why you would want to maybe use the G8 Tehcm is for the program in the Tehcm... I am not sure how it would work and if it would identify everything correctly if not flashed properly... that is why by using the G8 Tehcm would be easier overall.... (ps.. I am not a programming guy so I dont know how it would effect the trans if you use the 6L90 tehcm but by using the g8 tehcm it should work well... unless I am missing something on the programming part of it....??) but as for mechanically it is a pure plugnplay...

[mi04se1]

The tcm is the same part number. It wouldnt matter if you use the one the the 6L80, they are the same.

[gr8lover]

Quick update: 6L90 was installed in my car with no issues (temporarily)........ shifter exact same location, everything connects as in 6L80 except for rear mount and driveshaft. Everything clears and there is plenty of room for this to be installed. Only thing I didnt verify was if the pan would work and how much it would hang lower..... looks like everything around it clears but not sure on pan depth yet... I will have to look at the prints to check that. THe rear mount can be easily modified by either making new mount or cutting off two sides, making two extensions, and welding them on....due to the holes being shifted by about 34mm..

In my opinion I would get a new aluminum driveshaft made with slip yoke ... versus modifying current..... (i think would be better option..... new aluminum driveshaft and eliminate the current "tiny" driveshaft where it expands/retracts...) I was going to discuss with Chris at Gforce on when he will make it... :).. I am sure he would do this for us in a second when someone actually does it and needs it....

I will add pics tonight or tomorrow..... got to run to a Cinderella/Scorpions concert now......:) Good news overall for future mods....

[gr8lover]

The tcm is the same part number. It wouldnt matter if you use the one the the 6L80, they are the same.
thanks for the info.... that makes it easier!!!!

[gr8lover]

I'd still be worried about the tuning end of things. If you frag the Circle D 6l80 you're going to frag the 6l90, too...

Andy

I agree---- the tune is so important that hopefully it will be right... I am happy with Livernois and will stay with them on the tune.... I dont expect the Circle D rebuild will have any issues but just seeing what is possible for those that may want it or need it later on..... including myself. However, with the tune correct and good... the 6L90 is the monster we have been looking for and very easy to get into our cars... in my opinoin...

[VegasNate]

This is great stuff Chuck!! I'm waiting to see if this is a realistic solution for me too.

[Dave Ga]

I wish someone had been this smart months ago! I already paid to have my 6l80 redone and have more trouble already! everybody told me that the 6l90 was not a viable option for us when i broke my tranny the first time. i still think my tune is my main issue but, a6l90 would sure be nice, i am glad guys like you can get this done for the rest of us! keep up the good work!

[Tempest2000]

I'd be curious to see if a 6l90 holds up better than the 6l80... Hurry up someone has to try it out for the rest of us LOL

[Boostpatrol]

I am leaning towards just saying f*ck overdrives for what they really save me in fuel, cause dead cost for me to do a rossler 4l80 is 5k landed here in canada, plus a 1500 dollar controller, plus a driveshaft plus the headache of getting a speed signal to the ecm. Then theres the headache of all the testing of it. The 6l80e/90e will be a constant 1900 dollar uprgrade 2 to 3 times a season and it will still slip. So im likely gonna do a terminator 3 turbo 400 with brake from rossler in the winter.

[Robert@KBXPerformance]

I wish someone had been this smart months ago! I already paid to have my 6l80 redone and have more trouble already! everybody told me that the 6l90 was not a viable option for us when i broke my tranny the first time. i still think my tune is my main issue but, a6l90 would sure be nice, i am glad guys like you can get this done for the rest of us! keep up the good work!

Who did the work on your tranny?

[sherm6998]

I thought I should share this with all of you. I contacted Speartech about using a 6L90 in the G8 and this was their response:
"The electronics are the same between the 2 transmissions. The physical/mechanical differences are the only things you will have to deal with. The 6L90 can be flashed with your G8 program."

This means that any 2wd MYD (6L90) transmission can be sourced from a recycler and fitted into your G8. I found a few online for around $1500. Adding Red Alto clutches should be around $1000 with labor, so ~$3000 with everything (driveshaft modification, trans mount, flashing G8 program at a dealership, etc.) should get you an 800hp capable transmission!
Also, gr8lover; if you have any updated info, please continue to post. Thanks.

[gr8lover]

I thought I should share this with all of you. I contacted Speartech about using a 6L90 in the G8 and this was their response:
"The electronics are the same between the 2 transmissions. The physical/mechanical differences are the only things you will have to deal with. The 6L90 can be flashed with your G8 program."

This means that any 2wd MYD (6L90) transmission can be sourced from a recycler and fitted into your G8. I found a few online for around $1500. Adding Red Alto clutches should be around $1000 with labor, so ~$3000 with everything (driveshaft modification, trans mount, flashing G8 program at a dealership, etc.) should get you an 800hp capable transmission!
Also, gr8lover; if you have any updated info, please continue to post. Thanks.

I saw the same two for $1500..... if I wasnt redoing my complete engine now I would be buying one of them. They fit perfect and if you are going to get a new carbon fiber driveshaft from Gforce then it would be a perfect time!!!

[Boostpatrol]

In reading the ctsv forums... guys making 600whp are roasting 2 or 3 built 6l90s and running 11.07 at 127. Those def arent gonna work behind my motor. We are def gonna have to R and D this turbo 400 in my car then. Gotta find a way for engine to start without the stock tcm being there.

[G8-4-Speed]

if it can be flashed with a G8 TCM tune, then could the tune be upgraded to a cts-v tune for just the TCM? It has much higher tq maps to work withfor shifting and pressures.

[gr8lover]

if it can be flashed with a G8 TCM tune, then could the tune be upgraded to a cts-v tune for just the TCM? It has much higher tq maps to work withfor shifting and pressures.

I am not a controls or programming guru by any means.... (actually far from it)... but I would say you would want to tune the trans very similar to the CTS-V due the 6L90 being in the CTS-V..... just setup the program like the CTS-V or even refine some and you have a good package..... still not like a built up 4L60 or 4L80 but still much better than our 6L80.... it holds some promise for sure and much cheaper than trying to convert to a different transmission model....

[VETURBO]

Any Update on this>>

Has anyone completed the swap?

[wreckwriter]

We all chose different transmissions.

[Darkmanx]

That sucks