I pull a 10,500 lb. fifth wheel with a 2015 F250 6.2. Is it practical to manually apply the trailer brakes to assist the truck engine braking?

 

You can, but you shouldn't have to. I tow a much heavier trailer (15,000 lb. fifth wheel) with a 2010 F-350 6.8 and I rely almost entirely on engine braking on some very steep, very long downhill sections of the Rockies.

Are you seeing the engine braking engaging on downhill grades? I assume that you are in tow/haul mode, and a firm press on the brake pedal should cause an upshift (or two) and you will see rather high rpm's on the tach. Like 4000+. It doesn't hurt the engine at all and creates a huge amount of braking force.

The problem with using the trailer brakes extensively is that they will heat up and fade rather quickly (assuming drum brakes). And using the trailer brakes won't signal the truck to upshift to increase engine braking.

Some folks are reluctant to FIRMLY press the brake pedal to get the required upshifts for effective engine braking, but don't be. That is how the trucks are designed to work.

 

I brake as you suggest. However the 6.4 diesel previously owned did a FAR better job of braking. And yes the much higher RPM's take getting used to but I expected better braking performance from the gasser.

 

The 6.2 doesn't have true "engine braking" like the 6.7 does. Some call it exhaust braking on the 6.7.

In my opinion, you shouldn't be tweaking the trailer brakes on a downhill run. That assumes that you have the trailer brakes / brake controller set up correctly. Shifting your focus to the trailer brake controller takes your focus off of other things. The better approach is to gear the transmission down and let the engine/transmission slow you down, supplemented by application of the brake pedal to keep things reasonable.

 

Not true. Gasoline engines don't need external exhaust brakes because the throttle plate serves that function. With the tow/haul function keeping the torque converter locked the gasoline engines provide very good engine braking. You just have to spin them up to get the most they have to offer.

I can understand that my 6.8L engine may have more effective engine braking than the 6.2L based solely on displacement, but I'd be surprised if the reduction is much more than the difference in displacement (10% +/-).

One thing that I've noticed is that getting into the engine braking very early before speed has built up is a key to keeping things calm.

 

Good point on early braking. I need to start the process much earlier than my current practice. To stay below 50 mph I tend to wait til I get to 50. I guess that puts the truck at a bad position.

 

As an old trucker. Here is what I do whenever towing a rig without engine braking....whatever speed/gear I crest a hill/mountain in, I keep it there as I start down the hill. If I top a hill at 40, I just maintain 40 as I start back down.
This is oneof the sweet things about the Ford transmission, if you top the hill in say 3rd gear, you can just lock out 4,5, & 6 with the +/- toggle button on the shifter and keep it in 3rd and maintain control without overheating brakes.

 

Having come from a 6.4 as the op did, I found that using tow/haul and expecting engine braking was not as good for the 6.7. More than likely the same for the 6.2 If use put the trans in manual mode that should help to keep the speed in check.

 

Good advice. If the speed runs up to say 47 would you put on brakes til 2nd gear or just brake to 40 and expect the truck to speed up again?

 

Depending on engine RPM, if my method doesn't hold the rig, then if I can, force another downshift without overspeeding the engine. When braking, use the "stab" braking.....I.E. brake hard for a moment to rapidly decrease vehicle speed, but not so hard as to lock up wheels....then allow engine to hold vehicle speed by proper gear selection. This method will generate less heat than trying to maintain light pressure on the brakes. Hope this helps you

 

A what if question- what if I set cruise control on 45 mph- would my truck downshift on its on to hold 45? It does this when not towing or in "tow mode".

 

I'm running a 6.2 with 4.30 gears pulling a 16K trailer and when I go down big grades I use the manual mode exclusively, the torque converter is locked in the M mode so it's just like a manual transmission. My combination is heavy enough so the motor can't hold it back completely so I have to use some braking, I let the speed build and then use heavy braking to bring it back down and then let off so the brakes came cool between braking cycles. The big grades I'm referring to are in the Rock Mountains.

Denny

 

Without an" actual engine brake, I don't see much cruise control in the hills!! I actually "drive" the truck!! Only time cruise gets used is in the flatlands!! Now, with an effective engine brake, it is a different story!

 

May sound wierd but I will give it a safe try.

 

Yes on some grades it will in TH or D.

Denny