Hills/mountain descending?

Driving a truck isn't rocket science but for christ sake have a little pride in yourself and what you do.

 

I have been purposely laying off of the specifics on this threads for a multitude of reasons--and I am in NO WAY picking on or disagreeing with your basic points Steve--I am only using your post to make a point I have made many times throughout this(and other)forum and discussions,,,,,,,,,,,,
IMHO--it is not a good practice to discuss particular gears used(in any given situation)when dealing--especially w/newer drivers--while it may work as a guideline--the typical fatal flaw in this thought process is gearing---
A trucks gearing(rear end ratio)has MUCH more to do with gear selection--than almost anything else--including weight--and while weight in a downgrade is the MAJOR factor--it is still the gearing in the truck that will determine how much braking power has in any particular gear--and while many of the fleet trux may be very similar--it is again IMHO--not a good way to look at it--the old adage of one gear lower than you climbed the grade in still works very well--and is a much safer generalization---even in many of today's--hi torque low rpm motors..........
because as always--errin on the side of caution ALWAYS works..like the sayin goes--you can go down a mountain too SLOW forever--but---you can only go down too fast ONCE
Just my $.02
Be safe y'all

 

↑ ↑ ↑ THIS! ↑ ↑ ↑ (Post #62)

'olhand,, likely the best and most important post on this thread.
We too often mistakenly give out specific numbers (gears, speed, rpm's, etc) to others, but the fact is...
those numbers only apply to a driver's individual truck. A truck with a 3.25 rear end will be far different final gearing than one with a 4.11 rear end.
In other words, to simplify, YOUR 9th gear may be MY 8th gear (equal final combined gearing).

Roadranger has an online road speed calculator
Its primary purpose is to demonstrate/calculate road speed, with (3) user-selectable data of transmission final drive gear ratio,
tire specs/diameter, and target RPM. However it makes a great example of overall gearing, as you pointed out.

Here's a screenshot, just as an example (I set parameters at 0.75 final trans ratio, 275/80R22.5 tires, and 1500 RPM):

 

Great info, KW. Thx.

 

One reason would be for the oil to thin too much or just a Jake problem, a long time ago I drove a Pete built from a glider and after a while the Jake would fade out and just stop working.
It turned out that the engine had the wrong oil dipstick in it, it read full at about 4 gallons...the oil was overworked and the Jake quit working.

The last time before it went to Cummins it quit working on the downstroke of Mountain Pass, I 15 NB Cali/Nv border about a mile off the top on Friday evening traffic....that was a fun ride to the bottom.

 

If you lose compression, you've got no engine brake. No matter what mechanical failure. A broken drive shaft would do same. Heeeeeeeeyahh!

 

Makes sense as the jake uses hydraulic oil pressure to open exhaust valve early. No oil pressure, no jake.

 

To the OP(but applies to everyone) YOUR comfort level is the most important part of this equation. Nervous mistakes are almost always worse than stupid mistakes. DO NOT let anyone(Super Truckers on the radio, dispatchers etc...) push you beyond your comfort level, the only thing that raises your confidence and comfort level is experience period.

 

..............

 

going slow down grades is fine, but dont go to slow and drop the rpms to much that will kill the engine,and if its icy that should start a chain of events called the oh poop factor slow is fine just watch your rpms