Transmission shudder

16LT4 · September 17, 2022

I typically to a drain/fill every 25-30k miles on transmissions, and don't even bother with the multiple drain/fills within a short time interval anymore due to the frequency of replacement. Filter every 50k. I installed a drain plug in my transmission pan so a drain/fill is stupid-easy, and any particulate that has fallen out of suspension is removed as well. I also pour in a 10oz bottle of Lubegard Red on every fill to every transmission.

Here's the UOA on the ATF in my '08 E83, which has the GM 6L45 transmission. Not completely apples-apples compared to a 6L80/90 transmission, but not exactly Apples-Ford either. Other than fluids/filters, the transmission is completely stock at 190,500 miles, and has never offered a hint of shudder, trouble, or shifting issue. The fluid was last drained/filled at 165k miles, when the LG was added. Is there life left in the fluid? Sure. But as fluid and suspended particulate vary inversely, and my goal is to maximize the life of the unit, not the fluid. I'm too cheap to skimp on maintenance, and treat the K2 to the same service regimen as the old Roundel. The K2 is due for a fluid change in ~10k miles, and I'll send the fluid in at that point as well. I'm not concerned with the fluid as much as I'm looking for metals, especially in the 6L90 transmission, considering the known TC issues. Note Blackstone's comment about the amount of metal in this sample: proof that the LG works awesome? Not quite. Support for that hypothesis? Certainly. Also from experience, the LG works great for knocking out the shudder from an older, neglected transmission; it cured all shift issues in my '05 F150 FX4 which didn't receive its first ATF change until 145k miles.

Edited September 17, 2022 by 16LT4

pokismoki · September 19, 2022

On 9/2/2022 at 4:58 AM, virtuallyunlimited said:

Same issue here, 2014 Sierra, around 98K miles. To prevent it I can either put it in 5th gear, or put it in tow mode.

yeah , makes sense,since 5th gear disables v4 mode... if you go into the trans lock up and tcc slip tables, the settings for v4 mode is completly different tcc lock up slip, then when your on all 8 cylinders. the truck likes more slip when on 4 cylinders then when on 8 cylinders. i guess v8 smoothes the shakes out vs when on 4 banger mode

Edited September 19, 2022 by pokismoki

ACE86 · January 25, 2023

I have a 2019 Chevy Silverado LT. Took it in for rattling noise at 48k miles. Lifters and cam shaft were bad. Got it back and it shudders at coasting/maintaining speeds of 20-25, 30-35, 40-45...Shuddered bad once in a right-hand turn, right back wheel froze for a second. I call the dealer, of course the first said well maybe it's not a shudder, just a vibration from the tires. Smh..LOL...I said, Naaa, this is somewhere in that drive train; transmission, torque converter, drive shaft or somewhere. This was before I even new these forums and problems existed. It's going to the dealer tomorrow. WISH ME LUCK!!

Rob Seed · March 8, 2023

Have a 2015 GMC Sierra 4WD. Replaced tranny at 165K because TC was bad. At 185K and bad shuddering noise when going from V8 to V4 mode. Took it back to dealer they said it’s not TC it’s in drivetrain. Any thoughts would help. I’ve been keeping it in M5 and runs great!

Rob

JimCost2014 · March 9, 2023

On 3/8/2023 at 12:20 PM, Rob Seed said:

Have a 2015 GMC Sierra 4WD. Replaced tranny at 165K because TC was bad. At 185K and bad shuddering noise when going from V8 to V4 mode. Took it back to dealer they said it’s not TC it’s in drivetrain. Any thoughts would help. I’ve been keeping it in M5 and runs great!

Rob

Welcome to the site.

Did you ask if the dealer could possibly expand on their very vague statement about the driveline? At this point all you will get here are random guesses and stories about what was wrong with other trucks, which may or may not apply to your situation.

D. McKeithan · June 4, 2023

I have a 2018 Chevy Silverado 6.2l with the 8L90 transmission, which had the shudder and a hard shift since 50,000 miles or so, I'd change the transmission filter and fluid around 54,000 miles, shudder went away and returned around 58,000 miles.

At 72,000 miles I purchased a 12V vacuum pump, vacuumed the two oil cooler lines, drained the transmission and replaced the transmission filter, went back with 7 quarts of the AMSOIL special blend transmission fluid, and immediately the shudder went away and the shift is so much smooter.