Newbie asking for help with 8L90e tuning for TCC shudder New TC and Mobile 1 fluid

[pecothern]

I set up the Torque convertor pressure & lock-up speeds. I don't have the same OS to see if the TC apply ramp is stock, so return the ramp table to stock.

Russ Kemp

Hey Guys I am back with a quick question I am hoping Russ K will see this and respond. I am open to any suggestion from anyone also, I have been super happy with the way my transmission shifts since Russ helped me out. No more TCC shudder. I have made one addtl tweak to have the TC lock-up in 5th also, before was locking up 6,7,8. My issue today and it is not huge really only happens when pulling my 6x12 enclosed trailer that weighs about 2500 pounds,

When I slow down to a crawl but not completely stop and push the gas to start moving again the truck will lug and jerk. I usually stop completely then start and its fine also I can press gas maybe 50% and it will shift down and take off.
I suspected and confirmed with my autel scanner the trans stay in 3rd gear all the way down till 5 mph. So if I slow to 6 mph then press the gas I'm pulling off in 3rd gear and it feels just like trying to start rolling in my standard jeep in 3rd gear.

My question I guess is how to make the trans more aggressive with the DOWNSHIFT? I'm not sure where to start, I've noticed it rarely goes from 3rd to 2nd on the downshift. It usually drops from 3rd into 1st at 4.97 mph.

I've done the fast learn twice and as I said this usually is only a problem when pulling the weight of my trailer. BTW I do have the Tow button on, Current tune attached named
6.2 with russ 33.8 tiresize 5tccon.hpt (2.20 MB)

[pecothern]

I may have figured it out using tables tcm 15034 15036 and 15037 I'll flash tomorrow and see how it does

new tune with changes attached

[pecothern]

Wow I pulled my trailer around today and the truck does great. Essentially the current table stated downshift 3-2 at 5 mph and 2-1 at 5mph thats why it always bypassed 2nd and went straight from 3rd to 1st BUT not till 5mph I changed 3-2 to 11 mph and 2-1 to 6mph. The transmission shifts exactly like that now most of the time I get below 11 at least and it drops into 2nd and pulling off in second works fine. I am astounded the factory program had the truck not dropping out of 3rd till 5mph and bypassing 2nd all together. Are they concerned with mileage the would have me pulling off in third gear that is stupid, but now Ive learned I can control the shift points down to the mile per hour and TPS position I'm gonna really tweak it and get it exactly how I want.

[06Trophydiesel]

Hey Russ tried downloading this trans tune into TCm and it gives me an incorrect ID. Looks like the id for this file is for a T87 tcm the unlocked one I got from HPT is an T87a. Wonder if you could help me out. Thanks in advance.

[06Trophydiesel]

I set up the Torque convertor pressure & lock-up speeds. I don't have the same OS to see if the TC apply ramp is stock, so return the ramp table to stock.

Russ Kemp

Hey Russ tried downloading this trans tune into TCM and it gives me an incorrect ID. Looks like the id for this file is for a T87 TCM the unlocked one I got from HPT is an T87a. Wonder if you could help me out. Thanks in advance. Attached is the file/ tune i have in the yukon now. Its 2017 Yukon XL with the 6.2 8L90. marshall NEW NEW .hpt

[mechman22]

I set up the Torque convertor pressure & lock-up speeds. I don't have the same OS to see if the TC apply ramp is stock, so return the ramp table to stock.

Russ Kemp

Just want to say thank you Russ K!
First time tuning a GM transmission and this tune is great. I replicated the bulk of your changes to my base tune.
There?s no odd lag when accelerating, no harsh shifting coming off from coasting.
My Yukon feels like a new truck.
Really appreciate you posting to have something to compare.

[LSCALADE]

Can you please do something for me and confirm if it worked? On your scanner side when you start scanning, go reset your LTFT there is a button for it under the engine tab. I just spent 2 months dealing with saw tooth lock unlock on my car and horrible shudder and resetting this fixed my issues.

I tried everything, from cranking offset pressures to ramp up pressures, nothing seemed to move the TCC Line pressure any higher than about 45-50psi, and now it seems to climb all the way to 90psi even though the offset is set to 30psi.

Berfore LTFT Reset .jpg

After LTFT Reset.jpg

[[email protected]]

OK, so I?m fairly new to tuning. I have HP tuners and I did a flush on my transmission. I have a 2015 Sierra 6.2 with a 8L 90 shuddering but flushing helped big time but I?m a little scared to mess with the transmission, but I was going to look at your file, but I cannot see it like I can?t get it for whatever reason I could see your somebody else?s Feild down the way it?s in blue but you?re attached file I cannot see. I was just wondering if there?s anyway I could look at it and use it. Thanks for your time.