Tow haul mode?

Here's the explanation on the 6.4 Ford operation.

"I’ll try to explain. Exhaust braking closes off (blocks) the exhaust manifold, leaving the exhaust gases in the cylinders to compress and slow down the engine. Engine braking doesn’t allow fuel to be injected into the cylinder, so a vacuum is created in the cylinders, which slows down the engine, which is connected to the transmission and slows the truck down."

Copied from The Diesel Stop".

All I know is it works. Cruise control set on 60mph. It held it at 60mph down a long 6% (marked) grade. I never touched the brake. Grossing 18,100 lbs.

Proved it to me.

PS A jake brake and an exhaust brake are different things. Look up how a jake brake works on a big truck, no flapper vales, all done by holding open valves.

avvidclif1 wrote:
Here's the explanation on the 6.4 Ford operation.

"I’ll try to explain. Exhaust braking closes off (blocks) the exhaust manifold, leaving the exhaust gases in the cylinders to compress and slow down the engine. Engine braking doesn’t allow fuel to be injected into the cylinder, so a vacuum is created in the cylinders, which slows down the engine, which is connected to the transmission and slows the truck down."

Copied from The Diesel Stop".

All I know is it works. Cruise control set on 60mph. It held it at 60mph down a long 6% (marked) grade. I never touched the brake. Grossing 18,100 lbs.

Proved it to me.

PS A jake brake and an exhaust brake are different things. Look up how a jake brake works on a big truck, no flapper vales, all done by holding open valves.

The 6.4 doesn't have an exhaust brake - the 6.7 does.

What you describe is correct for the 6.4, just simple engine braking combined with the integrated brake controller and tow haul telling the torgueshift when to shift.

Not sure where the "jake brake" came into the discussion.

I have read where using exhaust brake on wet or snow slick roads is an invitation for disaster. If that is true, then an integrated exhaust brake with TH would prohibit use of that function under those conditions?

I think it is disabled if you come out of tow haul. Tow haul in itself can cause complications on ice

Atom Ant wrote:

avvidclif1 wrote:
Here's the explanation on the 6.4 Ford operation.

"I’ll try to explain. Exhaust braking closes off (blocks) the exhaust manifold, leaving the exhaust gases in the cylinders to compress and slow down the engine. Engine braking doesn’t allow fuel to be injected into the cylinder, so a vacuum is created in the cylinders, which slows down the engine, which is connected to the transmission and slows the truck down."

Copied from The Diesel Stop".

All I know is it works. Cruise control set on 60mph. It held it at 60mph down a long 6% (marked) grade. I never touched the brake. Grossing 18,100 lbs.

Proved it to me.

PS A jake brake and an exhaust brake are different things. Look up how a jake brake works on a big truck, no flapper vales, all done by holding open valves.

The 6.4 doesn't have an exhaust brake - the 6.7 does.

What you describe is correct for the 6.4, just simple engine braking combined with the integrated brake controller and tow haul telling the torgueshift when to shift.

Not sure where the "jake brake" came into the discussion.

Jake brake was an aside.

A diesel engine has almost zero engine braking as thought of in a gas engine. Ergo the exhaust brake to create a restriction. On the 6.4 Ford did things with the turbo to create a working "engine brake".

I don't like the way the transmission shifts in T/H,so unless I want the grade brake feature,I don't use it.

Pulling my 11,000lb trailer or my 10,000lb boat,the transmission actually runs cooler without T/H.

I like tow/haul mode because downshifts sooner to respond to hills, holds the gear longer, and engine-breaking automatically occurs at higher speeds.

If we r taking a poll, I only use mine when slowing down....
Even when not towing as the engine braking and tranny downshifts save my brake pads ( which aren't under warranty)

Other than slowing I don't usually use it as it holds the gears too long IMHO :.

And since its my truck hope I can drive it like I want to :-)