WOW!!!!

Drove a truck with a 450 Mercedes down a 4-1/2 mile 11% grade grossing 135,000 lbs decent at 7 mph, 2nd gear, full jakes (exhaust brake), engine fan turned on (helps with about 25 hp worth of braking) worked out just fine.
You definitely wanted to be at least into low range somewhere.

 

Could also be a broken wire from the switch to the solonoids.

 

Another possibility happened when my brother was at the wheel when we were teaming: jakes went out descending Cajon Pass. I got into the fuse panel in the glove box, started to jiggle the Jake fuse to pull it and inspect it, suddenly the jakes were working. After we finished the day we pulled all the fuse, blew an incredible amount off dust out of the sockets, then cleaned all the contacts before installing all the fuses again.

Electric gremlins are often caused by build up of dust.

 

The engine brake won't seem to do anything in high range when its that steep. You'd need to be in low range for it to start holding.

 

nicest mtn. road in the country

 

Good luck with that. No Jake and 20mph will over speed the engine. 8-10mph might even be too fast. 4th-5th gear down with no Jake. If it holds without too much braking, good to go.

 

I know the exact location of that hill....I ran Hunstville every week for years and got caught taking that short cut empty one night.
It goes through a residential area and the local cops watch it like a hawk!
Not sure but I think it is marked 13%...It is steep anyway.
If it is the same one it is called Little Cove RD. Runs off of hwy 72 to the south side of town and you pass a golf course.

 

I think maybe you should read what I said, I said 20 if your jakes are working perfect.

 

Hell.....all of these newer trucks do not have a real Jake anyway......just an exhaust brake.BIG difference!

 

sounds like it needs a name.