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**Guest** · 08-29-2022, 07:06 AM

Thank you in confirming setting to 6th gear to deactivate AFM on the 8 speed.

I would like to add that Ford has moved to cylinder de-activation to improve fuel economy. Stellantis already uses this feature which is referred to as MDS (Multi Displacement System). The internal combustion engine is far from dead where work continues to improve emissions and fuel economy. Sad part is we must adapt to the new technologies.

For newer trucks with Auto Stop Start, the (A) button will also need to be pushed to disable that feature at each drive cycle.

Jim

**familytruckster4** · 08-29-2022, 09:02 AM

I had the exact same rig and heard the exact same thing, it was the truck dropping down into 4 cyl mode. I was shocked at first that it didnt lock it out when in tow/haul mode, seemed kind of silly to expect a truck to go into 4 cyl mode while towing but then again, they didnt call and ask me for my opinion. This truck was leased, had I owned it and intended on keeping it I would have had a friend do the complete delete on it, cam and all.

**Guest** · 08-29-2022, 03:47 PM

Originally posted by familytruckster4 View Post

I had the exact same rig and heard the exact same thing, it was the truck dropping down into 4 cyl mode. I was shocked at first that it didnt lock it out when in tow/haul mode, seemed kind of silly to expect a truck to go into 4 cyl mode while towing but then again, they didnt call and ask me for my opinion. This truck was leased, had I owned it and intended on keeping it I would have had a friend do the complete delete on it, cam and all.

I know you were unhappy with the feature but its easy to select out of it or the dongle is much cheaper at $260 if it bothered you than much. I explained that to lock it out in Tow Haul would make this a defeat device where there is a penalty in doing that with the government.

I imagine you would be fuming with Stop Start added in.

Keep in mind it would be easy and much cheaper to sell a vehicle without these features where manufacturers are scrambling to meet stringent fuel economy standards. This is why all light duty V8 trucks will have AFM. Many V6 vehicles has it as well as some 4 cylinder applications such as the VW Golf as an example. And all light duty vehicles will have Stop Start where its already in light duty diesels. May even end up in the HDs some day.

Jim

**kd2600RB** · 08-29-2022, 03:57 PM

Originally posted by MidwestCamper View Post

I have a 6 speed with 3.42:1 final drive and the 5.3L and rarely am I out of 5th gear. I have no issues. However, I tow with 89 octane fuel.

Here is what I would suggest without actually looking over your truck.

1) Run ONLY top tier fuel in your truck. You will feel the difference in running top tier fuel if you have been running the discount fuels. I run shell since our Kroger points will transfer there as an example.

2) Run most of the regular grade fuel out and before your next trip, fill with 89 octane. This will allow the engine to learn out any bad stuff (general term to avoid an endless discussion) and will allow the transmission adapts to settle in as well.

3) Move your trans selector to (M) while underway and tap to 5th gear to disable AFM if that's an issue.

Your transmission should almost exclusively stay in 5th gear (D and Tow Haul) unless your traveling at much higher speeds with non towing traffic. I tow at 62-65 depending on wind where RPM ranges from 2100-2800 on hills.

Don't want to go off topic so send me a PM and we can discuss further if you like.

Torque Converter Shudder is the term your dealer was trying to convey where the 6 speed has been good and largely without issue in this regard.

Jim

I sent you a PM Jim. Hopefully it's in your inbox.

**Guest** · 09-12-2022, 09:52 AM

kd2600RB Ken,

I answered your PM but will post here to help others with the 8 speed who tow rigs in the weight class of the 2600RB. A former GM co-worker ran a test and confirmed his 8 speed truck will disable AFM in gears 6&7 in tap mode (L). I checked the gear ratios in comparing my 6 speed in tap mode 5 in towing our 2600RB where this ratio compares to 7th gear in your 8 speed. So choose tap mode in 7th gear and this will work favorably for you.

Jim

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