TCC shudder / tuning solution

EFI Tuning · 10-13-2017, 09:35 AM

I had the shudder start on my car last spring (MY16). I had the flush procedure done and for about 4 months it was resolved. Unfortunately the shudder has returned.

I noticed that if I command the TC to lockup manually (via HP Tuners) it goes to maximum pressure and it will not shudder at all. As of the most recent beta HP Tuners has added some additional TCC tables. I began doing some testing and for a few days now I have not had the shudder occur at all.

There are allowable slip tables per each gear relative to engine torque output. At low torque output GM allows up to 10 RPM of slip. This results in minimal pressure on the TCC apply. This is the design intent but because of whether it is a fluid friction modifier issue or a clutch material issue on the TC it allows the shudder to be felt.

I changed the table to allow 0 slip in 7th and 8th gear. This resulted in increased line pressure and the shudder does not occur. There is also a table that affects ramp rate of pressure based on slip but I did not need to touch that table.

I'm not saying don't go to the dealer and let them flush/replace the TC per the TSB but if you don't want to go that route it appears it can be mitigated via the TCM calibration.

I thought I'd share for the benefit of the community.

Tim

parish8 · 10-13-2017, 09:48 AM

That is great. I could have used this a year ago.

We probabbly want to 0 out the slip tables with an aftermarket converter?

EFI Tuning · 10-13-2017, 10:06 AM

On my car I have zeroed our all of the allowable slip tables. GM has to think about how the car feels to the average buyer so I get why they allow for some slip but in a performance application I don’t see the need. The apply ramp table will really dictate how abrupt the apply is. I did not notice any difference in feel after zeroing them out.

My Yank 3400 is going in soon. I will have to wait and see how it behaves before I can comment. But HP Tuners has exposed enough tables that I think it can be dialed in correctly. It’s a triple disc clutch in the Yank so I’m not sure what to expect in terms of feel. I’ve been told that this TC has really nice driveability characteristics.

GM had to appease the EPA and as a result we got this low pressure mode at low loads. Great in theory but obviously didn’t pan out well long term.

Tim

LibertyHill · 10-13-2017, 01:35 PM

Quote:

Originally Posted by EFI Tuning

GM has to think about how the car feels to the average buyer so I get why they allow for some slip

Please explain? Seems it would just generate heat, waste fuel.

EFI Tuning · 10-13-2017, 02:54 PM

To control parasitic losses at the high duty cycle areas (ie... cruising) they use a different pump (there are effectively two). Why they allow so much slip at cruising I do not know. The loss of TC slippage there may be offset by the lower parasitic losses of the pump in that zone.

If you have HP Tuners log your TCC slip while cruising in 8th. You will see how it behaves.

I will post if I see any issues with the tune approach but so far it has been rock solid. At high torque levels they move to 0 slip.

Tim

Darth Martel · 10-14-2017, 07:54 AM

Tim, my hat is off to you sir. That's an amazing discovery. GM has been doing testing to figure out what the deal is with this shuddering problem and haven't been able to figure it out. I'll pass this info to my buddy at the test facility and hopefully it will get to those who need it. I'll also pass this info to my tuner so, he can implement this fix. Hopefully, this fix works for everybody out there.

EFI Tuning · 10-14-2017, 09:13 AM

I won't claim it will work for everyone because I've only been able to test on my car. However, I've not had any issues since I made the table change. I'd love to see some other people test it out that are experiencing the issue.

If anyone has already tuned their TCM and want help on identifying the exact table to change let me know. The latest beta is required to access these tables. They are not yet available in the public release.

Tim

Darth Martel · 10-14-2017, 09:29 AM

Gotcha, thanks Tim

Darth Martel · 10-20-2017, 12:55 PM

Tim, I had Ted tune my TCM for me for this and other tweaks and it's like I have a new car. To be fair, I also had the triple flush done this week as well but, I had a day to drive around after the triple flush and still felt the car wanted to shudder but, didn't. After the TCM tune, the car doesn't want to shudder anymore. That convinces me that the TCM tuning is doing some good. I'm not noticing much difference in my mpg. Maybe a half mpg lower. I'll report back over time.

glenB · 10-22-2017, 08:27 PM

I would think the same reason the engine oil pump pressure is regulated by the PCM, the trans pump is regulated to achieve fuel mileage standards.

If increasing the pump pressure isn't causing any noticeable feel in shift quality then fuel mileage, as parasitic drag, would be the likely reason.

EFI Tuning · 11-02-2017, 12:32 PM

I'm glad to see someone else tried the TCM changes. I'm leaving my tables zeroed out with the Yank 3400. I see zero reason to allow any slip during lockup. I've also given my ramp rate table a bump of 20%. It feels crisp.

Tim

wrankin · 11-02-2017, 03:36 PM

Quote:

Originally Posted by EFI Tuning

I changed the table to allow 0 slip in 7th and 8th gear. This resulted in increased line pressure and the shudder does not occur.

Tim

Interesting information, and over my head.

I had the shudder at about 40 mph and in the 60 to 70 mph range also. Does that mean transition between some other gears need to be zero out too?

The flush has done the trick for now, but I see it comes back for many.

Bill

PolynesianPowerhouse · 11-02-2017, 04:23 PM

Quote:

Originally Posted by EFI Tuning

I had the shudder start on my car last spring (MY16). I had the flush procedure done and for about 4 months it was resolved. Unfortunately the shudder has returned.

I noticed that if I command the TC to lockup manually (via HP Tuners) it goes to maximum pressure and it will not shudder at all. As of the most recent beta HP Tuners has added some additional TCC tables. I began doing some testing and for a few days now I have not had the shudder occur at all.

There are allowable slip tables per each gear relative to engine torque output. At low torque output GM allows up to 10 RPM of slip. This results in minimal pressure on the TCC apply. This is the design intent but because of whether it is a fluid friction modifier issue or a clutch material issue on the TC it allows the shudder to be felt.

I changed the table to allow 0 slip in 7th and 8th gear. This resulted in increased line pressure and the shudder does not occur. There is also a table that affects ramp rate of pressure based on slip but I did not need to touch that table.

I'm not saying don't go to the dealer and let them flush/replace the TC per the TSB but if you don't want to go that route it appears it can be mitigated via the TCM calibration.

I thought I'd share for the benefit of the community.

Tim

You are possibly saving ALOT of people, the time away from their cars and the headaches of said issues.

Thats what some hace poasted saying the dealers were finding when they hooked up the computers.

With that being said, do you know of any tuners savvy with the v6 lgx in tuning with hp tuners on the 6th gen. I remember Matt @ FSP was a good go to on the LFX 5th gens.

I think in the future ill be in the market for remote tuning or dyno tuning.

JaxChris · 11-02-2017, 11:04 PM

This thread was started by one of the two people I would go to first for a safe email tune if you already own your own HPT cable and spent the credits on your vehicle. And for someone that hasn't gone crazy with their power mods, both of these guys are more affordable than Matt was.

EFI Tuning - Tim - Mt Dora, FL
Tampa Tuning - Phil - Tampa Bay, FL

Central Florida is lucky to have a number of good GM tuners. Not sure if Tim does LGX, but he is an E85 pioneer on the 6th gen (unfortunately no corn gas in the Aloha state). Phil does do LFX/LGX, but he charges +100$ over his normal fee for direct injection motors (including LT1/LT4/LTG as well).

10-13-2017, 09:35 AM	#1
EFI Tuning Drives: 2016 Camaro SS Join Date: Oct 2016 Location: Mount Dora, FL Posts: 792	TCC shudder / tuning solution I had the shudder start on my car last spring (MY16). I had the flush procedure done and for about 4 months it was resolved. Unfortunately the shudder has returned. I noticed that if I command the TC to lockup manually (via HP Tuners) it goes to maximum pressure and it will not shudder at all. As of the most recent beta HP Tuners has added some additional TCC tables. I began doing some testing and for a few days now I have not had the shudder occur at all. There are allowable slip tables per each gear relative to engine torque output. At low torque output GM allows up to 10 RPM of slip. This results in minimal pressure on the TCC apply. This is the design intent but because of whether it is a fluid friction modifier issue or a clutch material issue on the TC it allows the shudder to be felt. I changed the table to allow 0 slip in 7th and 8th gear. This resulted in increased line pressure and the shudder does not occur. There is also a table that affects ramp rate of pressure based on slip but I did not need to touch that table. I'm not saying don't go to the dealer and let them flush/replace the TC per the TSB but if you don't want to go that route it appears it can be mitigated via the TCM calibration. I thought I'd share for the benefit of the community. Tim

10-13-2017, 09:48 AM	#2
parish8 Drives: 17 SS a8 Join Date: Feb 2010 Location: omaha Posts: 1,678	That is great. I could have used this a year ago. We probabbly want to 0 out the slip tables with an aftermarket converter? __________________ dropped a valve in the 6.2. now running a drop in rods and piston 5.3 best et 5.83@121 with the 5.3 http://www.camaro6.com/forums/showthread.php?t=465472

10-14-2017, 07:54 AM	#6
Darth Martel Darth Martel Drives: Black 1SS with 20% tinted windows Join Date: May 2009 Location: Bizzaroland Posts: 1,496	Tim, my hat is off to you sir. That's an amazing discovery. GM has been doing testing to figure out what the deal is with this shuddering problem and haven't been able to figure it out. I'll pass this info to my buddy at the test facility and hopefully it will get to those who need it. I'll also pass this info to my tuner so, he can implement this fix. Hopefully, this fix works for everybody out there. __________________ 2016 Black 1SS w/ MRC, low-gloss black wheels, auto trans. Self-created custom Dark Knight Edition accents. Rotofab CAI with dry filter and sound tube delete, PRAY ported intake manifold and throttle body, Texas Speed cam, Stainless Works headers and exhaust, Skid Mark garage E85 kit, JMS fuel pump voltage booster, Circle D torque converter. Custom E85/mod tune by Jannetty Racing.

10-14-2017, 09:29 AM	#8
Darth Martel Darth Martel Drives: Black 1SS with 20% tinted windows Join Date: May 2009 Location: Bizzaroland Posts: 1,496	Gotcha, thanks Tim __________________ 2016 Black 1SS w/ MRC, low-gloss black wheels, auto trans. Self-created custom Dark Knight Edition accents. Rotofab CAI with dry filter and sound tube delete, PRAY ported intake manifold and throttle body, Texas Speed cam, Stainless Works headers and exhaust, Skid Mark garage E85 kit, JMS fuel pump voltage booster, Circle D torque converter. Custom E85/mod tune by Jannetty Racing.

10-20-2017, 12:55 PM	#9
Darth Martel Darth Martel Drives: Black 1SS with 20% tinted windows Join Date: May 2009 Location: Bizzaroland Posts: 1,496	Tim, I had Ted tune my TCM for me for this and other tweaks and it's like I have a new car. To be fair, I also had the triple flush done this week as well but, I had a day to drive around after the triple flush and still felt the car wanted to shudder but, didn't. After the TCM tune, the car doesn't want to shudder anymore. That convinces me that the TCM tuning is doing some good. I'm not noticing much difference in my mpg. Maybe a half mpg lower. I'll report back over time. __________________ 2016 Black 1SS w/ MRC, low-gloss black wheels, auto trans. Self-created custom Dark Knight Edition accents. Rotofab CAI with dry filter and sound tube delete, PRAY ported intake manifold and throttle body, Texas Speed cam, Stainless Works headers and exhaust, Skid Mark garage E85 kit, JMS fuel pump voltage booster, Circle D torque converter. Custom E85/mod tune by Jannetty Racing.

10-13-2017, 10:06 AM	#3
EFI Tuning Drives: 2016 Camaro SS Join Date: Oct 2016 Location: Mount Dora, FL Posts: 792	On my car I have zeroed our all of the allowable slip tables. GM has to think about how the car feels to the average buyer so I get why they allow for some slip but in a performance application I don’t see the need. The apply ramp table will really dictate how abrupt the apply is. I did not notice any difference in feel after zeroing them out. My Yank 3400 is going in soon. I will have to wait and see how it behaves before I can comment. But HP Tuners has exposed enough tables that I think it can be dialed in correctly. It’s a triple disc clutch in the Yank so I’m not sure what to expect in terms of feel. I’ve been told that this TC has really nice driveability characteristics. GM had to appease the EPA and as a result we got this low pressure mode at low loads. Great in theory but obviously didn’t pan out well long term. Tim

10-13-2017, 02:54 PM	#5
EFI Tuning Drives: 2016 Camaro SS Join Date: Oct 2016 Location: Mount Dora, FL Posts: 792	To control parasitic losses at the high duty cycle areas (ie... cruising) they use a different pump (there are effectively two). Why they allow so much slip at cruising I do not know. The loss of TC slippage there may be offset by the lower parasitic losses of the pump in that zone. If you have HP Tuners log your TCC slip while cruising in 8th. You will see how it behaves. I will post if I see any issues with the tune approach but so far it has been rock solid. At high torque levels they move to 0 slip. Tim

10-14-2017, 09:13 AM	#7
EFI Tuning Drives: 2016 Camaro SS Join Date: Oct 2016 Location: Mount Dora, FL Posts: 792	I won't claim it will work for everyone because I've only been able to test on my car. However, I've not had any issues since I made the table change. I'd love to see some other people test it out that are experiencing the issue. If anyone has already tuned their TCM and want help on identifying the exact table to change let me know. The latest beta is required to access these tables. They are not yet available in the public release. Tim

10-22-2017, 08:27 PM	#10
glenB Drives: Chevrolet Camaro SS Join Date: Mar 2015 Location: Planet Earth Posts: 721	I would think the same reason the engine oil pump pressure is regulated by the PCM, the trans pump is regulated to achieve fuel mileage standards. If increasing the pump pressure isn't causing any noticeable feel in shift quality then fuel mileage, as parasitic drag, would be the likely reason.

11-02-2017, 12:32 PM	#11
EFI Tuning Drives: 2016 Camaro SS Join Date: Oct 2016 Location: Mount Dora, FL Posts: 792	I'm glad to see someone else tried the TCM changes. I'm leaving my tables zeroed out with the Yank 3400. I see zero reason to allow any slip during lockup. I've also given my ramp rate table a bump of 20%. It feels crisp. Tim

11-02-2017, 11:04 PM	#14
JaxChris Drives: '16 2SS GD1 MX0 NPP F55 IO6 Join Date: Jun 2013 Location: Florida Posts: 1,298	This thread was started by one of the two people I would go to first for a safe email tune if you already own your own HPT cable and spent the credits on your vehicle. And for someone that hasn't gone crazy with their power mods, both of these guys are more affordable than Matt was. EFI Tuning - Tim - Mt Dora, FL Tampa Tuning - Phil - Tampa Bay, FL Central Florida is lucky to have a number of good GM tuners. Not sure if Tim does LGX, but he is an E85 pioneer on the 6th gen (unfortunately no corn gas in the Aloha state). Phil does do LFX/LGX, but he charges +100$ over his normal fee for direct injection motors (including LT1/LT4/LTG as well).

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