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If your Silverado, Sierra, Tahoe or Yukon does a little shudder around 45 mph when you're barely on the gas, and the fluid comes out dark on a truck that never pulls anything, you've probably heard the line already. "These just do that."
They don't. Burnt fluid comes from heat. Heat in a transmission comes from slip. And on a GM truck with AFM, the slip is programmed in, on the easiest miles you drive.
Since 2007, GM's Active Fuel Management (DFM on newer trucks) shuts off 4 of your 8 cylinders at a light cruise to save a little gas. Here's what that does to your transmission, and what changes with FullForce.
A V8 on 4 fires half as often and every pulse hits harder. That's the deep rumble around 40 to 50 mph you've been blaming on the road.
Locked, the converter would send that shake into your seat. So the programming lets its clutch slip on purpose to hide it. GM's own patent (US8052575) describes it.
Slip is friction, and friction is heat that goes straight into your fluid. It darkens, breaks down and wears the clutch, which means more shudder and more slip.
Fresh fluid goes back into the same system. Next highway drive, the engine drops to 4 again and the new fluid takes the same heat on day one.
Repair costs are owner reported on GM owner forums. Your shop's price will vary.
No tools, no app, no tuning. It works on your very next drive.
| Other optionsFlush · Rebuild | BEST FullForce | |
|---|---|---|
| Stops the AFM slip at cruise | ✕ | ✓ |
| Fresh fluid stays out of the daily slip | ✕ | ✓ |
| Reversible in seconds | ✕ | ✓ |
| No shop visit | ✕ | ✓ |
| Install time | Shop visit | About 30 sec |
| Cost | Rebuild $3,000+ | $89.95 |
FullForce is prevention, not a repair. If your transmission already slips or throws codes, have it inspected first.
Add to cartSee what drivers like you are saying
"Truck feels stronger, shifts smoother, and no hesitation when towing. Been running it for a while with no issues."
Ryan P.Verified buyer
"After dealing with lifter issues around 100k miles, I didn't want to risk it again. Put this on my 2015 Silverado and it's been running smoother since."
Meggan M.Verified buyer
"No issues, no codes. Does what it's supposed to. Easy to install and take off if needed. Worth it."
Brad C.Verified buyer
"Glad I picked it up. No problems so far. Used to get in and mess with settings, now I just get in and drive."
Marcus F.Verified buyerNo, and you would not want it to. FullForce turns off AFM. With the engine on all its cylinders there is no 4 cylinder shake to cover up, so the converter is not told to slip at cruise and its clutch can stay locked the way it was built to.
No. It is not a transmission repair and it will not undo wear that is already there. If yours already slips, flares or throws codes, have it looked at first. FullForce takes away the reason the converter was slipping on your easiest miles.
Yes, keep up your normal service. The difference is that fresh fluid is no longer going straight back into a slipping converter on every cruise.
It does not reprogram anything. Unplug it before you drop the truck off and it is back to stock.
Expect about 1 mpg less, because the engine stays on all its cylinders. That is roughly what AFM was saving.
You have a 60 day money back guarantee, plus a lifetime warranty on the unit. Free shipping, usually 3 to 5 days.
