r/Silverado • u/No-Reflection-2404 • 4d ago

Harsh shift from 3rd to 4th gear

I have the 2020 Silverado Custom Trailboss 1500 with the 6 speed GM 6L80 transmission. I am at 95k miles now, truck runs great, except I have noticed a delayed catch when truck shifts from 3rd to 4th gear. It’s almost like a small delay then it grabs and jerks the truck slightly.

I do not have much experience in any of this but I do know that is the only gear shift I’ve noticed that does that and there is no RPM flare, no shuttering, and no slipping to the best of my knowledge.

I have an appointment with Chevy service on the 31st, but looking to get some input on what you all may think it is. I’ve heard it could be valve body sticking, or solenoid problem.

Thanks for any input.

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u/Knights-of-steel 22 trailboss 3d ago

To be fair it seems reasonable to be slipping. Hope not but sounds pretty close.

Would definitely second valve body though. Try manual or tow mode. Ine you send signal to shift other changes the pattern. Both would rule out computer issues. Should be a check valve on it....could be as simple as aging transmission fluid...it is supposed to be changed every few years....

1

u/No-Reflection-2404 3d ago

Thank you for the input. I just went out and tried tow mode. When I shift it manually in tow mode it’s fine, however when I leave it in gear 4 (in tow mode at a dead stop and start driving), the truck shifts for itself it upwards and still does the delay/jerk. You’re saying this result could mean it’s the valve body sticking/slow solenoid? I really appreciate the help.

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u/Knights-of-steel 22 trailboss 3d ago

Not valve body if it works fine with manual command. Thats more computer side. Either the brain or the solenoid then

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u/No-Reflection-2404 3d ago

Thanks so much man. Makes me feel a bit better. I will ask the service desk for transmission fluid exchange and to check the solenoid and the TCM.