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Showing results for tags 'tcc'.
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Hello all. I am a semi-frequent user of GMTrucks.com. I’ve had several cosmetic and suspension modifications to my truck (Bilstein 5100’s, roadactive suspension, hellwig rear sway bar, interior mods), nothing major in the drivetrain. I just crossed 50,000 miles, and it looks like yet another TCC failure (first one at 24,500 to 25,000 miles). It’s a 2020 Custom Trail Boss, 4.3. When the first converter failed, they ended up putting 2 thermal bypass valves in it. After the last TBV change, transmission never sees over 150°. What do I need to do to have GM put a better converter in my truck to prevent future hangups (sonnax, maybe)? How should I approach this to ensure I don’t keep losing my truck for weeks at a time? I don’t overload it, I don’t dog it, and the fluid still looks clean (changed with last thermal bypass valve at 30,000 miles, total fluid exchange and filter replacement). It seems like every 25,000 miles, I’ll be back for another torque converter. I don’t haul or tow frequently. When I do, it’s usually no more than a single axle utility trailer with some light household refuse, or an enclosed single wheel with a flat track motorcycle in it. Bike weighs 600 pounds. Tongue weight below the 1,760 payload rating on the sticker in the door. I’ve never gone more than about 40 miles when towing. Usually interstate or rural rustic road (55 mph and no traffic) Any suggestions? I really like the truck and don’t want to trade it in. It suits me for what I need, and I’ve put a lot of time and love into this machine. -
2017 Silverado LT 5.3 4X4 6speed transmission 51,000 miles When I first bought the truck the transmission suffered from severe bucking or shudder under light load. GM calls it chuggle. The cause was "intermittent tcc delamination causing scoring on fluid pump". They replaced the torque converter, cover housing and pump cover along with a flush. This was at 10,000 miles. That seemed to solve the chugging problem. For the last year or so I have noticed that the torque converter unlocks and locks frequently at freeway speeds. When it locks, following an unlock, there is a noticeable lurching forward. This is not neck snapping but is definitely noticeable. This lurching motion also occurs when upshifting 4/5 or 5/6. While driving at freeway speeds (65 70mph) when I slightly let off the accelerator the rpm's rise about 200 then settle down. If I should slightly press down the same thing happens. However, when driving at a steady freeway speed, and holding steady on the throttle, on level ground I can feel this unlock/lock along with seeing the engine speed move up then settle down. If I engage cruise control on level ground it is worse and occurs more often. But, with cruise control on and there is a slight road incline there is no unlock or downshift. When I press hard on the throttle then it downshifts and accelerates fine. Locking/unlocking and lurching; I do not recall the transmission behaving like this in the early years. The dealer says if it doesn't throw a code then it is operating normally. I can see that there are times when it should unlock such as when under load, but should it be this happening this frequently and be so noticeable? Or maybe I am being too sensitive? Anybody experience the same thing? Is this normal transmission behavior? -
Hello all! First post here! What brought me here was the 8l90 torque converter lockup shudder issue. Most times I'd just take this truck to the dealer and let them sort it out, but as it's out of warranty, this is not something I'd like to pay >$600 to repair (this price was quoted to me for the flush and filter change). After talking to a few service advisors I've found that each of them planned on using a different solution to attempt to alleviate the shudder. The first was going to proceed via one of the bulletins and do a triple fluid swap and filter change, the others were just going to do a standard flush and fluid swap. I plan on owning this vehicle for another few months until the 19's become a little more negotiable but cannot stand to let this shudder go on that long and am a bit worried about destroying the torque converter in the process and washing a whole bunch of parts down into the transmission. So.... my question is if anyone has performed this fluid swap themselves, if it alleviated the issue, and if the filter change is necessary? I saw that many of the Corvette guys were swapping to the Mobil 1 fluid with some success, however, I didn't think this was as much of a fluid performance issue as it was a suspended clutch material / dirty fluid issue. Any help would be greatly appreciated!!!!!!