91RS

iTrader: (8)

I bought my 2008 thinking it was going to need a transmission and I ended up replacing the filter and resetting the adapts and have been driving it for 4 years. It has never shifted super nice like my old 12 or my 13 even after having it tuned (that did make it much better) and with 157k on it I've been considering replacing or rebuilding it as preventative maintenance. I know there are some updated seals and other parts that came in 2009 (IIRC) and I've seen some people use Sonnax's Zip Kit but I can't seem to find a good list of the parts that would need to be replaced to upgrade this transmission. I don't know if I should just buy the Zip kit and then order a GM seal kit and clutches for my year and go with that or try to order upgraded/updated parts but I don't know what I need. I don't know if I should go ahead and replace the TEHCM or just buy the rebuild kit Sonnax sells for it. Or I could just do a torque converter and the Zip Kit and keep on driving it.

I've also seen a lot of talk about an "upgraded" torque converter but haven't really seen where people are getting these from. I do NOT want an aftermarket higher stall converter. I put a Yank 3200 stall in my TBSS because the TBSS forum said it was a "must have" and I absolutely HATED it and I will never do that again. I might be ok with a slightly higher stall (no more than a couple hundred RPM) but I want it to be able to function exactly like the stock converter and the clutch not just be on-off. Seems like the CTS-V/ZL1 torque converter may fit the bill but I'm not sure if the flex plate needs to be changed also and if a stock one will work or if aftermarket would be needed. I don't tow much but I still want to be able to tow if needed. I also want to do a torque converter in my 2013 to prevent failure so I'll likely be buying two of whatever I decide on (the 13 has 170k miles but shifts great, I'll probably do the Zip Kit on this one as well). So far the only other converter I've considered is the Circle D 300mm Pro Series Triple Disk which has an option for 1800-2000 stall which should be fine but it is pretty spendy at $1000 so I think I could get the ZL1 converter and a flex plate (if that is even needed) for a good bit less.

FFDP

iTrader: (2)

Can't help on the rebuild kit parts but for the torque converter a stock 6L90e or a new OEM 6L80e converter will do just fine.

In the calibration you can do changes to the settings to make that converter last a long long time.

RDF1

I've had very good luck out of the billet converters from Transtar.
Got a buddy in Louisiana that rebuilds the 6l80/90s for me and there are quite a few updates and stuff that goes into those transmissions.

91RS

iTrader: (8)

What about the flex plate though? The LSA has an 8 bolt crank so that flex plate won't work. If I have to buy a $350 aftermarket flex plate then I think it would be easier to just go with the Circle D converter for $1000 that will bolt right up (in theory).

91RS

iTrader: (8)

Maybe it isn’t even worth doing. Maybe I’ll just get new OEM converters and be done. They’ve lasted 157k and 171k miles. The 08 is already tuned so I’m sure the slip has been reduced or turned off and I’ll probably get the 13 tuned to disable the AFM and hopefully not need to do a cam and lifters any time soon.

jclark10

iTrader: (1)

So I've heard and there is videos and threads about people putting in the CTSV 6L90 (24045127) converter. I think that PN is sold as a "GM Performance Part" not sure if that is the OEM number as well and maybe if the OEM number is cheaper.

People use their stock 6L80 flex plate as well and just leave the extra 3 bolts off.

Also I am the same exact way, I hate things that ruin the stock driveability and "luxuriousness". I bought a Circle D 8L90 stall that was supposedly their closest to stock like converter. It ended up not locking up correctly and slipping during lockup and I had to pull the whole motor out again and send it back to them. It also has a POS crappy rattle sound in P/N from the unloaded clutch plates moving around which they fail to mention will happen. I ended up putting my stock converter back in and ended up selling it for half the price after I got it back from Circle D after they went through it but they never said if they had to fix anything or not. So I asked the guy that bought it but never heard back if it worked or not. Either way it wasn't worth it to me to go through all of the trouble of reinstalling it and taking a chance it doesn't work again, as well as the rattling noise did it in for me and I just decided to go with stock. I may try to do a stall again in the future from someone else besides Circle D but its good to know all the quirks of what you are getting into before the big commitment.

Anyway you know you can be safe with a stock GM converter and not have those issues. Not sure what the stall speed will be but they advertise 2000-2400.

I bought my 2011 6.2 L9H 6L80 AWD Denali with 245k and at about 250k it started making a whirring noise in 1st and some other gears. After tearing into it I found what appeared like something hard dropped into the gear mesh and broke a few teeth off then spit it out in the pan since everything looked almost brand new with no major looking wear. So not entirely convinced it was just old age or fatigue that made it fail but can't think of anything that could break off and get in there.

Anyway I ended up buying a new GM rear planetary and the clutches and valve body and everything else looked perfectly fine with almost no wear. Some of the clutch packs may have looked a little darker than some of the others but I put it back together with the new planetary and Sonnax zip kit and line pressure booster and didn't replace any seal or bearings just used the stock ones with supposedly 250k miles. Not sure if the transmission was ever rebuilt or replaced in its life though.

So I'm at about 260k now so about 10k with my turbo setup at 10 lbs and everything seems ok. Still running stock torque management and using LS9/CTSV virtual torque tables. I've probably done at least a few hundred boosted launches at about 4-8 psi also. I will say though it seems like once the transmission gets to temperature above maybe 170F, I can start hearing a very faint whirring/wining noise coming to a stop when it downshifts into first gear. Also I have seen the trans slip pid report up to about 100 rpm for just one frame of the log in first gear during a boosted launch. Not sure if this is the stock clutches about to go (I forgot which clutch is on during 1st but I know the sprag is holding in 1st along with the lo/reverse clutch but lo/reverse only holds below like 4 or 5 mph. Not sure how much is considered just noise and how much is real slip, but I know all the other gears usually stay below about 20 or 30 rpms until its time to shift. However it still seems to meet the commanded shift times, around .450 or so, I keep them about stock. Sometimes though, and not sure if its due to the Sonnax line pressure booster or not, but it will shift hard, and before I had a lot of turblence in my MAF setup it would shift at about .125 seconds which was scarying me and I though it was going to fatigue some parts. Fixing the turbulence in the MAF with a longer tube and screen/straightener mostly fixed it.

Anyway, rebuilding the 6L80 is not hard, the only thing you need is a big pair of snap ring pliers (like the size of tree pruners) and a way to hold and compress some ridges on some of the drums to get the clutches out but that's really it unless you want to get bushing drivers and stuff like that.

Also looks like Transgo just came out with a new supposedly "performance" shift kit as there really wasn't one before. The Sonnax zip kit I think is advertised more as a problem fixer type thing and the line pressure booster from Sonnax probably has little effect.

91RS

iTrader: (8)

I hadn't read anything about noise with the Circle D but I definitely don't want any noise, I can't deal with that. So, you just went back to your stock converter? Not even the ZL1 converter?

I also didn't realize the zip kit wasn't a "performance shift kit" until after I bought them for both trucks but at least maybe it'll help. I ended up using a CVC reman 6L90 converter with a billet housing from Transtar in the 2013 but didn't go through it or anything. I want to go through the 2008 when I do it but I don't know what converter I want to go with, I may just do the Transtar there also.

smokinlmm

You can buy a zl1 converter for stock stall. Best bet is the hd2 shift kit, raybestos power pack with wave delete and new apply plates with blue Pistons. I also added red eagle clutches to every pack the raybestos Kit didn't include. Shift great and seems to be holding up to my stroker.

I have a single disk billet cover converter for the 6l80 that I put about 1000 miles on Id sell you for a song and a dance. Lol...

jclark10

iTrader: (1)

Yes I put in my stock converter back in with supposedly 250k miles. I guess it's possible someone before had replaced the transmission not sure.

I think the whole converter issue and people complaining about the horrible slipping that's killing the concepts converters in 100k miles is way overhyped and it's also commonly repeated by everyone everywhere so it gains more of like a cure all theory when something breaks.

I still have my tcc slip speed at the stock settings in both my 6L80 and 8L90 because I'm weird and want the stock luxurious experience with no perceived vibrations. I had the shutter on the 8L90 but that's because GM put in the wrong fluid and it absorbed moisture. It was fixed with the correct fluid but I will say as it has rolled over 100k I now feel and hear the torsional crank vibrations at TCC locked and low rpms. But that's in a stiffer chassis than a body on frame truck.

I know of a 100% stock 2012 6L80 that's never been opened even once and the fluid has never been changed, touched, or added and it's got close to 300k on it but I disabled the AFM at probably around 150k or so, but it still should slip even not under AFM although the AFM slip speed might be a little more. Either way the total power flow going through the clutch when the TCM is commanding slip to help with crank vibrations is relatively low so the TCC clutch is designed and can easily handle the slip and heat.

91RS

iTrader: (8)

This was the info I was looking for, I’ve been surprised there doesn’t seem to be much info out there about upgraded parts. My 08 is cammed but it’s maybe 50hp over stock and I kept the VVT. So I don’t really need big power handling but I’m more interested in nicer shifts but not so harsh it’ll spill a drink in the cup holder when it shifts or a bunch of noisy stuff. I’ve been very very careful with everything I’ve done to this truck to improve but not ruin what it’s supposed to be. This truck has done a great job and making me not like my cammed SS nearly as much as I used to.