Newbie asking for help with 6L80 basic TCC tune to get rid of shudder

[nftrans]

We are a transmission shop and have been building a lot 6L80s. Have been using precision torque converters for a long time with no issues/shudder without tuning anything. Now we are getting a lot of them back with shudder and slip in the torque converter even though we haven't on the previous hundreds we have done. Have been just replacing torque converters with another precision and then shudder goes away. Precision saying we need to tune the TCM, I bought the MPVI3 and plan to try this. Have watched and read a lot, from my basic understanding I need to put 317 mph in the 1-3 TCC apply tables and turn off DOD. I have also read to increase line pressure by 10%, is this something I will want to do as well to help the torque converter? I guess what I am looking for is something I can have my techs do to each transmission so we do not see shudders back. I am very new to this but am willing to try a basic trans tune someone uses. I also see people share files? Not sure how this works. Thank you for any input.

[5FDP]

For the most part the transmission changes are the same for most vehicles but there are some minor differences between generations of computers. Like GEN 4 and GEN 5 computers on the V8 trucks and maybe the cars too.

Do you have any files on hand from anything you are working on yet?

Then it would be easier to show what simple changes can be made to that file or a very similar file. This way you'd have a good idea of what you want to change going forward.

[mikez71]

One newb to another..

I frequently hear about people zeroing the 'TCC desired slip' tables.
Have also heard STOCK converters don't like it as much..

tccslip.png

The experts here will hopefully correct, or go into detail on this..
If you do search here, there should be a few threads on it..

[5FDP]

It's okay to disable the converter on gears 1-4 but only reduce the slip to something like 5-8rpm if it's a stock converter on gears 5 and 6.

The stock converter doesn't like zero slip from what we have learned. Just let it slip a minimal amount to keep it happy while hoping to reduce wear. Aftermarket converters with better material can do zero slip.

I also raise the shift mph for gears 5 and 6. Push them out to 40ish mph and 50mph. I hate how they shift into 6th at like 40mph.

[2xLS1]

If Precision converters didn't used to shudder and now they are they need to figure out what they are doing different/wrong on their end. Stock replacement parts shouldn't require tuning the TMC. I have worked for a few local transmission shops that won't use anything but GM OEM converters on their 6Lxx builds for those reasons. Not saying tuning the TCM won't help with some 6Lxx issues but it shouldn't be required on a stock vehicle.

[abc]

I would use a different TC company or price out OEM only. Once you get into modifying the calibration file you will open a whole new can of worms. I'm not saying it's a bad can of worms but for a general trans. shop, you will have a hard time justifying your time and getting paid for it. I suspect you would ultimately loose money in the long run.

Now, if people are coming to you for modifications, that's a different story.

In my opinion, in order to make the trans. and TCC function better, the customer will feel what the trans. is doing much more. Explaining that to a general cust. will eat up time your not getting paid for and I imagine most won't be happy that it doesn't feel like it did when it was new even though you are extending the life of their investment.

[hjtrbo]

Late to the party, I agree with previous comments. The problem lies on the suppliers end. Nothing worse than a supplier saying something needs tuning and not being able to supply a tune file to go with it that they'll warranty. It's a blatant cop out. I'd be looking for a new supplier with a solid warranty.

[woodchuck611]

It's okay to disable the converter on gears 1-4 but only reduce the slip to something like 5-8rpm if it's a stock converter on gears 5 and 6.

The stock converter doesn't like zero slip from what we have learned. Just let it slip a minimal amount to keep it happy while hoping to reduce wear. Aftermarket converters with better material can do zero slip.

I also raise the shift mph for gears 5 and 6. Push them out to 40ish mph and 50mph. I hate how they shift into 6th at like 40mph.

Hey new member here - Just to confirm your statement here: Zeroing TCC slip for 1-4 is okay for stock converter. But for gears 5 and 6, only reduce slip to 5-8rpm? I can send you my tune file if needed.

[Tfoggy]

Just get rid of TC lock up in gears 1-3 for sure. Some do 4th gear too, depending on application.
I let mine lock up in 4th as it's a big suv-Yukon XL 6.2 and I tow with it.
Bring up all gears shift tables a few mph so it's not in the higher gears right away
Decrease the slip to minimal if stock TC. (of course no DOD?AFM allowed) - that's part of the reason
they design it to slip so much and often

[5FDP]

Correct, you can disable the lock up in gears 1-4. Then just lower the slip rpm to like 5-8rpm if it's a stock converter in gears 5 and 6.

[TGMachine]

Correct, you can disable the lock up in gears 1-4. Then just lower the slip rpm to like 5-8rpm if it's a stock converter in gears 5 and 6.

Why wouldn't you change the slip to 0?

[RC2]

Why wouldn't you change the slip to 0?

0 is not realistic with the stock converter, it will jack the pressure up trying to maintain it and never actually get there.

[Alvin]

So far in my experience.

A loose converter will need help getting the TCC to lock.. Especially over the stock converter. Going from stock tight OEM converter from locked to unlocked is barely noticeable. If its a 2800.. than the RPM have to drag down quite a bit to make a lock.

I've not had any bad experiences zeroing out the TCC slip tables. I also raise the base TCC apply pressure.. something around 65 psi typcially will get it.. Sometimes I'll go a touch higher.

I don't think that 1-4 lock is necessarily bad.. I think it just can add to a busy shifting/locking transmission. With the stock converter like I said.. its barely noticeable. but if its a loose converter you'll definitely know when it's on and off.

If the TC is loose.. or the car has a good bit of cam buck I'll make it so it won't shift into 6th unless it can also lock the converter. So for most of these builds it will ride around at 45mph in 5th. This feels really good and natural. I think this is also easier on things as opposed to riding around with a unlocked converter building heat. Or trying to keep TCC locked against a bucking engine.

I've also fixed a fair number of completely stock trucks with the TCC shudder on 6 and 8 speeds mostly. Usually by raising base TCC pressure + limiting or eliminating slip.

I can't guarantee this is the right approach but so far this has served me well for several years now. There was a period where completely stock GM trucks especially had a terrible TCC shudder. I think GM fixed it by changing the fluid. But this was a real thing just a few years ago.

[namethattune]

So far in my experience.

A loose converter will need help getting the TCC to lock.. Especially over the stock converter. Going from stock tight OEM converter from locked to unlocked is barely noticeable. If its a 2800.. than the RPM have to drag down quite a bit to make a lock.

I've not had any bad experiences zeroing out the TCC slip tables. I also raise the base TCC apply pressure.. something around 65 psi typcially will get it.. Sometimes I'll go a touch higher.

I don't think that 1-4 lock is necessarily bad.. I think it just can add to a busy shifting/locking transmission. With the stock converter like I said.. its barely noticeable. but if its a loose converter you'll definitely know when it's on and off.

If the TC is loose.. or the car has a good bit of cam buck I'll make it so it won't shift into 6th unless it can also lock the converter. So for most of these builds it will ride around at 45mph in 5th. This feels really good and natural. I think this is also easier on things as opposed to riding around with a unlocked converter building heat. Or trying to keep TCC locked against a bucking engine.

I've also fixed a fair number of completely stock trucks with the TCC shudder on 6 and 8 speeds mostly. Usually by raising base TCC pressure + limiting or eliminating slip.

I can't guarantee this is the right approach but so far this has served me well for several years now. There was a period where completely stock GM trucks especially had a terrible TCC shudder. I think GM fixed it by changing the fluid. But this was a real thing just a few years ago.

Thank you Alvin. I have a 2010 Suburban that has had 2 replacement transmissions after the first one went out at 264,000 miles. The next 2 were never right and had bad shudder and rumble strips making the truck almost undrivable - transmission shop told me nothing they could do about it. She is now at 297,XXX. A desperation purchase of an HP Tuner and few tunes later and she drives great (DOD delete, TCC lock out 1-4 and full lock up in 5,6 - need to adjust speed for 5 - 6 as you mentioned) but I think I'll need to lower my TTC line max pressure. If you don't mind me asking how high do you go?

[jaywiz]

So far in my experience.

A loose converter will need help getting the TCC to lock.. Especially over the stock converter. Going from stock tight OEM converter from locked to unlocked is barely noticeable. If its a 2800.. than the RPM have to drag down quite a bit to make a lock.

I've not had any bad experiences zeroing out the TCC slip tables. I also raise the base TCC apply pressure.. something around 65 psi typcially will get it.. Sometimes I'll go a touch higher.

I don't think that 1-4 lock is necessarily bad.. I think it just can add to a busy shifting/locking transmission. With the stock converter like I said.. its barely noticeable. but if its a loose converter you'll definitely know when it's on and off.

If the TC is loose.. or the car has a good bit of cam buck I'll make it so it won't shift into 6th unless it can also lock the converter. So for most of these builds it will ride around at 45mph in 5th. This feels really good and natural. I think this is also easier on things as opposed to riding around with a unlocked converter building heat. Or trying to keep TCC locked against a bucking engine.

I've also fixed a fair number of completely stock trucks with the TCC shudder on 6 and 8 speeds mostly. Usually by raising base TCC pressure + limiting or eliminating slip.

I can't guarantee this is the right approach but so far this has served me well for several years now. There was a period where completely stock GM trucks especially had a terrible TCC shudder. I think GM fixed it by changing the fluid. But this was a real thing just a few years ago.

Alvin,
This sounds exactly what my problem is! I recently upped the cam (btr stg 2) and while the motor was out i upgraded to a 2600 stall converter. The truck was tuned by someone else and now i have random shudder issues. Soon as you let off the throttle some it goes away and off you go. The previous tuner refuses to adjust and says the tune is right where it should be (so that's why I'M here). However, i have only ever tuned older stuff and am learning A Gen 5 is not where to cut your teeth and i may be in over my head.any and all help would be very appreciated.

[Estep40511]

I have a stock billet faced converter in my 2014 truck, with a stage 2 cam. Been going for 3 years now and I have had it unlocked in 1-3 and slip speed set at 0. I have always used Mobil 1 HP in my 6L80 and it has the Sonnax Zip kit in it. not sure if that helps it or not, but never had an issue (knock on wood lol).

[Acrosteve]

What are the different patterns in the Gen5 file? A, B, Hot Trans, Hot Engine etc.

And the D2, D1?

[Acrosteve]

Pattern A tow haul mode?