Tips for straight trucks steep grades

If it less than a 400 HP engine, might not have enough compression to hold your weight. Some medium duty trucks have lower HP ratings, usual engine size is less than a 13 liter block, might have just an “exhaust brake”, not an actual Jake Engine Brake. Sounds like that might be the problem.

From the Jacobs Vehicle Systems website:
In it's simplest description, the Jacobs Engine Brake converts a diesel engine into an air compressor. All other factors being equal, the larger the engine displacement, the more powerful an air compressor it can make, and the higher the retarding performance.

 

Gear down. 35 may be too fast.

IF the engine fails to hold her while Jaking, you may have hit a steeper section. Use your brake to firmly and slow down to about two or three gears down. Reestablish the jake.

Never mind the RPMs too much, Jakes will give you more braking towards the red line provided you have adequate oil pressure, adequate but not overhot oil temp and a overcooked pyro.

There are some mountains I don't go down at 35. 17 or so is more like it.

We don't go by MPH here obviously. So, slow down to where the jake will hold her at a constant speed all the way down. That is a perfect run.

 

You don't know how to control the truck, using the engine brake (which more likely you have an exhaust brake on that truck) and gearing down won't do it, you have to use your brakes.

Don't be afraid to use the brakes, they are there for a reason. Nothing like hitting 60 mph going downhill and hitting something.

here is a good thread about stab braking.

Stab or Controlled Breaking Which Best/Fastest ?

 

I know it's too late now, but was it an automatic, a manual tran?
Also, were the brakes properly adjusted?
If this is a rental, and you're not familiar with the equipment you won't know to look for these things.
34k is not that heavy for the Wyo grades if you're brakes are properly adjusted and you drop on or two with the Jacobs engaged.

Next time you're in this position, and not certain, find a truckstop and look for an old timer ( one not wearing flip flops and pajama pants will be your first clue... jeans, boots, and a coffee mug will be a good tell) and ASK him to give a quick look.
Any good driver worth their salt would look for someone that had the grit to admit they needed help.
I WOULD HELP, AND I HAVE.
I've helped older folks in RVs , people in Uhauls, Coaches, etc.
We have knowledge... ask for it in real time.
Don't be embarrassed.