Experiencing what feels like a shudder on the 1-2 shift at slow speeds as well as at around 2000 RPM in OD (no other gears). Wondering if this is TC shudder? I know that the TC's are prone to go and when they do, they take the trans with it
I'm in Dallas metroplex
Lived in DFW metro for a decade, great place.
preface this with: I've got a 6L80 trans so not apples to apples
-and-
In the end, it's a decision you'll make based on your financial situation and your plans for the truck.
My truck first started the TCC shudder in Nov 2020. Took few months to figure it out. Had suspicions, they were confirmed in June '21 for $93 by mechanic. Been driving in M5 (manual mode 5th gear max) ever since to keep from reaching 6th gear and trying to lock up.
Mine has never exhibited any shudder at the 1-2 shift, but Ive felt it so many times in 6th gear between 40-65mph I can describe it in my sleep.
There are several other things it could be. There's also several diff ways to confirm it's the TC causing the vibration. Pretty much all of them require specialty tools that you may never use again though. The cheapest is probably the oscilloscope($50ish). (Pretty sure I've got an article explaining how to use it for this somewhere? Let me know if you want it) Or you can pay a shop you trust to diagnose it for you.
You can also feel for it yourself on any flat road that transitions to a mild incline (metroplex has dozens). Get the truck up to 55-60mph on flat section and hold your foot with just enough pressure to maintain speed and the trans should lock-up with flywheel via the TC. When you start up the hill the amount of torque needed to maintain that speed will increase. There's a (not so)sweet spot in there where the extra torque required is not enough to cause a downshift but IS enough to cause the TCC to lose it's grip on the TC housing.....and you'll feel --duh-uh duh-uh duh-uh-uh-uh duh duh-- The tachometer needle will bounce along with the slips (mine from 2000 down to 1700 then to 1850 then 18 then back to 2000 for a second then back to 1800 then....you get the picture). Those duh-uh's are happening because the TCC and the TC housing are not the same shape(think two different style dinner plates) and that duh-uh is also rubbing TCC clutch material off(think spray-in bed liner) which then goes through the trans and starts gumming everything up, causing heat, friction, eventual failure.
**To (I hate to say confirm but) confirm that is what's happening: When the duh-uh'ing starts and without moving your right foot at all, gently and barely depress the brake pedal with your left foot. Like an 1/8th of an inch, just enough to make light come on. **If the vibrations stop, it's most likely TCC Shudder** The TCC won't/can't lock-up with the brake switch engaged. I recommend repeating this a few times so you know you're doing it correctly
There's numerous videos on youtube about this subject.....numerous!
From what you described, I would change the TC, and have the TCC lockup tuned out of my truck, and drive it. The trans may go the next day or may last forever? but if it goes it won't hurt the new TC(as long as you don't try and drive around after).
If you want to better understand what's happening, read these:
Last October, I was lucky to spend a few days with Bob Warnke, the Vice President of Technical Development at Sonnax Corporation. He did the big 13+ hour drive to come to SIU so I could help him record and edit his seminar for Expo. In exchange, I gained a wealth of information regarding torque […]
gearsmagazine.com
A common problem for many General Motors cars is when the Torque Converter Clutch (otherwise known as TCC) fails to release. Learn how to diagnose it.
www.liveabout.com
Sorry for being so long-winded. This subject is what started my education on modern computer controlled vehicle systems. Spent dozens of hours reading/researching. Talked to engineers at Sonax, Circle D, Valvoline, GM, Lube Guard...technician at my local dealership. It taught me what planned obsolescence was, and obviously I took it personal lol
