Custom Tune Review!

[jdwood1111]

@NickTransmissions Hey Nick! I have been seeing you getting really active here and I am relatively new as well and trying to contribute but my current job and 5 kids keep me busy. I was hoping to maybe get your opinion on my situation which I will summarize below so you do not have to read through all the thread or others. Here is the quick history and issue:

2011 - Yukon XL Denali w/ 97k. Bought 1 year ago at 92k and its a second vehicle with unknown history.
Drove it to FL and noticed a rough 3-2 and 2-1 downshift when coming to a stop ONLY when trans was hot. It kind of banged into gear.
Took it to 2 tranny shops, 1 drove like a grandpa and said it was fine and the second said he drove it hard and it never skipped a beat. I had him change the filter and fluid since I was not sure of the history and he reported the pan was clean as was the fluid.
The truck definitely seemed to shift better and then I never got the tranny hot enough to feel the rough down shift over the winter and decided to have it tuned.
Wouldn't you know, the week before taking it to the scheduled tune, it resumed the harsh downshift when coasting to a stop. ALL other gears shift fine.

Went through with the tune and he greatly improved the shifting and he felt the rough down shift and I THINK he decreased the pressures for the 3-1, 3-2 and 2-1 downshifts and it definitely made it better but still not great. He increased the pressures a bit and that made it worse. It basically seems like when going from 3-2 the rpms want to rise a bit and it slowly goes into gear. Again, all other gears are fine.

I was going to throw a reman Sonnax valve body from Rock Auto and rebuild the pressure switches but not sure that will resolve the problem and did not want to waste time and money. I did just order the clone Tech2 so I can run some diagnostics but not sure how to use it.

Any input is greatly appreciated!

 

[NickTransmissions]

@NickTransmissions Hey Nick! I have been seeing you getting really active here and I am relatively new as well and trying to contribute but my current job and 5 kids keep me busy. I was hoping to maybe get your opinion on my situation which I will summarize below so you do not have to read through all the thread or others. Here is the quick history and issue....

Any input is greatly appreciated!

Hey @jdwood1111 - The only 'normal' 6L80 intermittent harsh downshift condition is one associated w/vehicles equipped with a 5.3L where the harsh downshifts are associated with a vehicle self test of the O2 sensors. This occurs as speeds above 45 mph where the ECM commands the O2s to adjust and run the engine rich momentarily then cuts off the fuel for a split second to test O2 response. This split second transition from rich to lean will case a mildly harsh downshift if one occurs because the torque converter clutch remains applied (i.e. in lock up) during the test.

The above out of the way, harsh downshift conditions in these transmissions can be due to:
1. Adapts (or lack thereof) resulting from either mechanical issues, programming changes -- a fast adapt may correct the issue) or TEHCM-related problems)
2. Torque converter clutch apply and release out of synch with clutch apply and release timing due to either tuning or converter clutch or internal components wear
> did the tuner do anything in the TCC tables to change the apply/release speeds or mess w/the torque management?
3. Wearing/worn compensator feed regulator valve - this valve is specifically tasked with 'smoothing' shift feel (laymen's explanation)
4. Wearing/worn torque converter clutch regulator valve (lower valve body), TC control valve or limit valve (pump)

Any codes being set (i.e. check engine light on)?

High on my list of suspects is the valve body, pump and torque converter, especially #3 and #4 as they will essentially be the underlying causes if #2 (failing converter) is the proximate cause. Anytime I see shifting issues only after a transmission gets warm, it's almost always worn valve trains or excessively worn clutches (though worn clutches would be indicated via slipping or flare shifting, which isn't in your description of the problem so would rule that out).

Next Steps
> Consult your tuner and get his thoughts on performing a fast adapt relearn to see if simply resetting the TCM back to factory settings fixes the problem (simplest option, least LOE/expense)
> If a fast-adapt doesn't fix the problem, I would pull the valve body and TEHCM and replace w/a Sonnax reman and overhaul the TEHCM (verify it's in serviceable condition prior to overhaul)
> If you were local to me, I would test your valve body assemblies (upper and lower) to confirm my hypothesis so as to avoid spending money if you don't have to (i.e. the problem is the converter or valves in the pump, not the valve body)
> If the entire valve body passed the testing and the tuner didn't see anything problematic with the TEHCM or the values in the various transmission shift strategy tables, including the TCC table then the next step would be to pull the unit and test the pump cover valve trains then perform a teardown and inspection of the main case, focusing on the 2-6 clutch pack, 1-2-3-4 clutch pack and low-reverse clutch pack as all are involved in the 3-2 and 2-1 down shift process.

 

[jdwood1111]

@NickTransmissions thanks for your quick response and information! Where are you located by the way? So to respond in order:

-No check engine lights or codes according to a scan with the GM Tech2.

1. Adapts (or lack thereof) resulting from either mechanical issues, programming changes -- a fast adapt may correct the issue) or TEHCM-related problems)
Can I do this with the Tech2? Is it worth using the Tech 2 to check the solenoids that I found in the unit?

2. Torque converter clutch apply and release out of synch with clutch apply and release timing due to either tuning or converter clutch or internal components wear
> did the tuner do anything in the TCC tables to change the apply/release speeds or mess w/the torque management?
I have downloaded HP Tuners and have my tuned file but I have not gotten the base file to compare it to. However, in comparing it to another yukon file I found, it appears he did change some things in both the apply/release and torque management. However, I had the problem before he made any changes anyway. He improved it slightly.

3. Wearing/worn compensator feed regulator valve - this valve is specifically tasked with 'smoothing' shift feel (laymen's explanation)
Is this in the pump or the valve body?

4. Wearing/worn torque converter clutch regulator valve (lower valve body), TC control valve or limit valve (pump)
Again, would a Sonnax valve body correct this?

> Consult your tuner and get his thoughts on performing a fast adapt relearn to see if simply resetting the TCM back to factory settings fixes the problem (simplest option, least LOE/expense)
Is this necessary if A, I can do it with the Tech2 or B, since I had the problem before he made any changes? Of should i reset to factory settings and then do a relearn?

> If a fast-adapt doesn't fix the problem, I would pull the valve body and TEHCM and replace w/a Sonnax reman and overhaul the TEHCM (verify it's in serviceable condition prior to overhaul)
So this would be the Sonnax reman valve body and then test the electric solenoids via the Sonnax rebuild videos before replacing the pressure switches?

> If you were local to me, I would test your valve body assemblies (upper and lower) to confirm my hypothesis so as to avoid spending money if you don't have to (i.e. the problem is the converter or valves in the pump, not the valve body)
I would think if it was the converter i would have issues at other shifts, no?

> If the entire valve body passed the testing and the tuner didn't see anything problematic with the TEHCM or the values in the various transmission shift strategy tables, including the TCC table then the next step would be to pull the unit and test the pump cover valve trains then perform a teardown and inspection of the main case, focusing on the 2-6 clutch pack, 1-2-3-4 clutch pack and low-reverse clutch pack as all are involved in the 3-2 and 2-1 down shift process.
Are you familiar with HP Tuners that if I sent my file to you it would be advantageous or not? I am slowing doing research to try and confirm this but its beyond my quick understanding. I am going to try and meet with the tuner to ask him some questions but I do not want to be a pest about it either.

 

[NickTransmissions]

@NickTransmissions thanks for your quick response and information! Where are you located by the way? So to respond in order:

-No check engine lights or codes according to a scan with the GM Tech2.

1. Adapts (or lack thereof) resulting from either mechanical issues, programming changes -- a fast adapt may correct the issue) or TEHCM-related problems)
Can I do this with the Tech2? Is it worth using the Tech 2 to check the solenoids that I found in the unit?

2. Torque converter clutch apply and release out of synch with clutch apply and release timing due to either tuning or converter clutch or internal components wear
> did the tuner do anything in the TCC tables to change the apply/release speeds or mess w/the torque management?
I have downloaded HP Tuners and have my tuned file but I have not gotten the base file to compare it to. However, in comparing it to another yukon file I found, it appears he did change some things in both the apply/release and torque management. However, I had the problem before he made any changes anyway. He improved it slightly.

3. Wearing/worn compensator feed regulator valve - this valve is specifically tasked with 'smoothing' shift feel (laymen's explanation)
Is this in the pump or the valve body?

4. Wearing/worn torque converter clutch regulator valve (lower valve body), TC control valve or limit valve (pump)
Again, would a Sonnax valve body correct this?

> Consult your tuner and get his thoughts on performing a fast adapt relearn to see if simply resetting the TCM back to factory settings fixes the problem (simplest option, least LOE/expense)
Is this necessary if A, I can do it with the Tech2 or B, since I had the problem before he made any changes? Of should i reset to factory settings and then do a relearn?

> If a fast-adapt doesn't fix the problem, I would pull the valve body and TEHCM and replace w/a Sonnax reman and overhaul the TEHCM (verify it's in serviceable condition prior to overhaul)
So this would be the Sonnax reman valve body and then test the electric solenoids via the Sonnax rebuild videos before replacing the pressure switches?

> If you were local to me, I would test your valve body assemblies (upper and lower) to confirm my hypothesis so as to avoid spending money if you don't have to (i.e. the problem is the converter or valves in the pump, not the valve body)
I would think if it was the converter i would have issues at other shifts, no?

> If the entire valve body passed the testing and the tuner didn't see anything problematic with the TEHCM or the values in the various transmission shift strategy tables, including the TCC table then the next step would be to pull the unit and test the pump cover valve trains then perform a teardown and inspection of the main case, focusing on the 2-6 clutch pack, 1-2-3-4 clutch pack and low-reverse clutch pack as all are involved in the 3-2 and 2-1 down shift process.
Are you familiar with HP Tuners that if I sent my file to you it would be advantageous or not? I am slowing doing research to try and confirm this but its beyond my quick understanding. I am going to try and meet with the tuner to ask him some questions but I do not want to be a pest about it either.

@jdwood1111 ,

Here are my responses to your questions (yours in bold, my responses are in reg font below them)

Can I do this with the Tech2? Is it worth using the Tech 2 to check the solenoids that I found in the unit?
> Yep, the TECH2 or any bi-directional scan tool that has adapt functionality will do the fast adapt
> You can fully bench test the solenoids for mechanical function using a Kent Moore test plate and TECH 2 (full comprehensive test) and use a multimeter to evaluate electrical health though if you had a solenoid or pressure switch issue, chances are you'd throw a code by now (but not always).

Review this article for the TEHCM testing procedures.

> Using a multimeter to test resistance for shift and pressure control solenoids (shift solenoids: 20-40 ohms; line pressure/clutch pressure control solenoids: 3-8 ohms).

clutch pressure control solenoid


shift solenoid


Pressure switch resistance (closed circuit): .7-1.9 ohms ( this is pressure switch #1 which sends a signal to the TCM reporting the status of the 3-5-R clutch reg valve in the valve body)


Pressure switch resistance (open circuit, pressure applied to switch) 11.5-12.9 kohms

Use pencil eraser to put pressure on switch to open circuit

Pressure switch resistance should drop back to .7-1.9 ohms or so (may vary a bit but should not be significantly different)

If any of those pressure switches are not reading like the above when you do this test, then the TEHCM is bad and should be replaced!

Is this (compensator feed regulator valve) in the pump or the valve body?
> It's in the lower valve body which is the half that faces you when looking up at the transmission from below

Is this (consulting the tuner) necessary if A, I can do it with the Tech2 or B, since I had the problem before he made any changes? Of should I reset to factory settings and then do a relearn?
> This is a question for your tuner when you meet up w/him. Since he made changes to the factory transmission control strategy he's best suited advise if a fast adapt should be done prior to resetting all values to factory or not.

So this would be the Sonnax reman valve body and then test the electric solenoids via the Sonnax rebuild videos before replacing the pressure switches?
> Yes but pull your valve body assembly and do whatever solenoid testing you can prior to spending the money on a new valve body as they DO NOT come with a new TEHCM, IMS, Harness or Speed Sensors

I would think if it was the converter I would have issues at other shifts, no?
> Maybe, maybe not. When the TC starts to go, the symptoms can vary in the earliest stages. I'm not suggesting that it is converter, only that it can potentially be. You'd have to go through the diagnostic progression to rule in or out all of the possible causes (direct causes and contributory causes) of your drivability symptoms. So (1) test solenoids (no DTCs makes solenoids unlikely to be your issue), (2) test valve body. If valve body fails testing, either install valve body reconditioning kit or purchase re-man valve body assembly. If TEHCM and VB pass all tests, (3) remove trans, pull and test pump. Even if the cause is found in the pump, at this point it only takes an additional 30 minutes to tear down and inspect the trans so (4) tear down and inspect transmission for mechanical failures.

You have to keep progressing through the diagnosis until you have found the cause(s).

Are you familiar with HP Tuners that if I sent my file to you it would be advantageous or not?
> Unfortunately, I wouldn't be able to assist w/interpreting or assessing the tune as I have no experience with tuning (HP Tuners or otherwise). I just rebuild the transmission. If there's a tuner involved in the project, I would provide to him an inventory of all mechanical hydraulic calibration mods performed so he can account for those in his tune.

If I was a full service shop (i.e. had bays w/lifts and performed the removal/reinstallation), I'd probably hire a tuner or learn the software myself so that I can take over that part of the service delivery chain but as of now I just to carry out builds. When the transmission leaves my shop, the owner has a tuner come by to do the fast adapt once it's back in the vehicle and ready or tows it to the dealer for the reinstallation and fast-adapt.

Hope that helps you!

 

[jdwood1111]

@NickTransmissions

Sorry for the delay but family stuff and work were crazy and I was not really driving the truck much until recently when kid activities started back up. In doing so, the 3-2 downshift and sometimes 2-3 shift are still not great. Mostly still just the downshift. All other gears seem ok so my plan at this point is follow mostly what you said and I am going to buy the Sonnax reman valve body from RA, test out the Ohms on the TECHM and replace fluid and see how it performs. Then I will review things with my Tuner if needed after that since this issue was already in play before he did the tune. He actually smoothed it out a bit.

However, in reading through the Sonnax and GM manual, for the trans adapt that must be done anytime the valve body is removed, they both say the transmission needs to be up to 158 degrees in one place and 185 in another. I RARELY see these temperatures unless I am in stop and go traffic after driving for a while. If it is 158, that may be alittle more doable. How will I get the transmission that hot without driving it once all this work is complete to use my Tech 2 to try and perform the trans adapt correcty?

 

[NickTransmissions]

@NickTransmissions

Sorry for the delay but family stuff and work were crazy and I was not really driving the truck much until recently when kid activities started back up. In doing so, the 3-2 downshift and sometimes 2-3 shift are still not great. Mostly still just the downshift. All other gears seem ok so my plan at this point is follow mostly what you said and I am going to buy the Sonnax reman valve body from RA, test out the Ohms on the TECHM and replace fluid and see how it performs. Then I will review things with my Tuner if needed after that since this issue was already in play before he did the tune. He actually smoothed it out a bit.

However, in reading through the Sonnax and GM manual, for the trans adapt that must be done anytime the valve body is removed, they both say the transmission needs to be up to 158 degrees in one place and 185 in another. I RARELY see these temperatures unless I am in stop and go traffic after driving for a while. If it is 158, that may be alittle more doable. How will I get the transmission that hot without driving it once all this work is complete to use my Tech 2 to try and perform the trans adapt correcty?

You won't have a problem getting to required operating temp. Here's a video showing the fast adapt procedure being done by someone with an Autel scanner. His temps were around 180-190 for most of the test.

 

[jdwood1111]

You won't have a problem getting to required operating temp. Here's a video showing the fast adapt procedure being done by someone with an Autel scanner. His temps were around 180-190 for most of the test.

Well any other suggestions? Now that’s it’s been cold out I cannot get and keep the trans above 158 degrees. I drove it to VA and back and it was around 123 on the highway and it would go up to 165 in traffic but cool off and then every time I park it, it just cools off lol. I just want to try and reset the adapts since the 3-2 shift is not getting any better and now I am noticing an occasionally rough 4-3. It gets a little jumpy going from 2 back from 3 but that I think is a tune thing. I pulled into my driveway and it was 158 and I let it idle for 10 mins and it went down to 139.

 

[NickTransmissions]

Well any other suggestions? Now that’s it’s been cold out I cannot get and keep the trans above 158 degrees. I drove it to VA and back and it was around 123 on the highway and it would go up to 165 in traffic but cool off and then every time I park it, it just cools off lol. I just want to try and reset the adapts since the 3-2 shift is not getting any better and now I am noticing an occasionally rough 4-3. It gets a little jumpy going from 2 back from 3 but that I think is a tune thing. I pulled into my driveway and it was 158 and I let it idle for 10 mins and it went down to 139.

Yes - Why in the world did you wait until now to do the fast adapt (or did you do a fast adapt in September and it didn't resolve the symptoms?)?

If you had done the F/A in Sep (assuming you haven't) you would have had no issues keeping a 158+ trans temp. Now, in the winter not so sure...Maybe get it in a heated garage or take it to a shop/dealership?

Your symptoms don't sound like 'tune-related' to me but I could be wrong...Do whatever you have to do get and keep trans temps up then run the relearn procedure using your TECH2. Once complete, drive it and monitor/assess its behavior. If you continue to have drivability symptoms, take the next step (tune / re-tune / modify existing tune)..If that still doesn't work, trans has to be worked on.

 

[jdwood1111]

Yes - Why in the world did you wait until now to do the fast adapt (or did you do a fast adapt in September and it didn't resolve the symptoms?)?

If you had done the F/A in Sep (assuming you haven't) you would have had no issues keeping a 158+ trans temp. Now, in the winter not so sure...Maybe get it in a heated garage or take it to a shop/dealership?

Your symptoms don't sound like 'tune-related' to me but I could be wrong...Do whatever you have to do get and keep trans temps up then run the relearn procedure using your TECH2. Once complete, drive it and monitor/assess its behavior. If you continue to have drivability symptoms, take the next step (tune / re-tune / modify existing tune)..If that still doesn't work, trans has to be worked on.

So I took 3 stabs at it back in September and still couldn’t get it hot enough. Every free chance I had it was a cooler day believe it or not it would not stay hot! Then I started working days, nights and weekends and with 5 kids at home including a 8 month old, I don’t have a lot of free time lol. Unfortunately I can’t fit the truck in my garage.

Been a little frustrated with the truck but my lack of time doesn’t help. Bought the truck 18 months ago in great condition with everything working and since then, the trans is acting as described, slight oil leak from I think oil pan gasket, pass side view mirror stopped moving, dash cracked on drivers side and started getting a slight valve tick. Otherwise it rides great and I love the truck!

My goal was reset adapts and then I have been waiting for the Sonnax valve body to drop in price on rock auto again if it ever does and do that in the spring for sure.

 

[NickTransmissions]

So I took 3 stabs at it back in September and still couldn’t get it hot enough. Every free chance I had it was a cooler day believe it or not it would not stay hot! Then I started working days, nights and weekends and with 5 kids at home including a 8 month old, I don’t have a lot of free time lol. Unfortunately I can’t fit the truck in my garage.

Been a little frustrated with the truck but my lack of time doesn’t help. Bought the truck 18 months ago in great condition with everything working and since then, the trans is acting as described, slight oil leak from I think oil pan gasket, pass side view mirror stopped moving, dash cracked on drivers side and started getting a slight valve tick. Otherwise it rides great and I love the truck!

My goal was reset adapts and then I have been waiting for the Sonnax valve body to drop in price on rock auto again if it ever does and do that in the spring for sure.

Gotcha...Yours is a great problem to have, except when it comes to doing fast adapts! Most folks struggle to keep those things cool and burn up the transmission so it's good to know the transmission is able to shed heat very efficiently. Drive around with the TECH2 hooked up and transmission live data displayed...look at various things like shift speed, torque converter efficiency and pay close attention during 2-3 and 3-4 up and down shifts to see if anything anomalous pops up in the data. Feel free to reply back w/photos of what the TECH2 displays if there's any question about the numbers, etc..