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08-23-2010, 06:43 PM
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#1
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Montana Master
Join Date: Jul 2006
Location: Pasco
Posts: 986
M.O.C. #5972
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Mountain Driving
I need some help on a mountain driving question. I have '02 F350 diesel with a PacBrake. I do not have a tow/command package. As far as I know the Pacbrake and the brakes on the trailer (3575RL) are adjusted properly. Why is it on long downgrades that I have trouble controlling the descent? Are there adjustments on the Pilot Commander that are internal that need to be adjusted for more braking capacity? Would it be to my benefit to downshift from drive to D2 - I have never tried that? I have always just let the transmission do it's own thing. I know these are basic questions I should have figured out by now, but, I have not yet figured it out. I do limited mountain driving. It just seems that the downgrades should be simpler than they are.
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08-23-2010, 07:16 PM
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#2
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Montana Master
Join Date: Jun 2007
Location: St.Maries
Posts: 1,010
M.O.C. #7329
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If you are in a lower gear you will have more rpm's and the exhaust brake would work better. A good rule is to go down in the same gear you went up.
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08-24-2010, 10:12 AM
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#3
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Montana Master
Join Date: Sep 2004
Location: Leona
Posts: 6,382
M.O.C. #2059
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Mike,
Don't you had a way to kick it out of over drive? Should be a button in the end of your shifter lever if you have automatic. Kicking it out of overdrive adds a little resistance. On long, steep grades, down shifting can be helpful.
When I had the F250 with the 7.3 L, I made sure I really controlled the down hill speed. Slower speed gave me better control. When having to stop on a down hill run, I always started early.
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08-24-2010, 10:09 PM
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#4
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Montana Master
Join Date: Jul 2006
Location: Pasco
Posts: 986
M.O.C. #5972
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I remember the rule-of-thumb about gear up to gear down. I had forgotten about the overdrive, jeez. I agree with you Stiles, I like to be in control from the top of the hill all the way down with no worries.
BTW, Stiles, are you coming to the annual meeting in the Tri-Cities. That's where I am. There may be a space in the park I am in if you want to bring your rig.
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08-25-2010, 04:48 PM
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#5
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Montana Master
Join Date: Oct 2009
Location: Indian Land
Posts: 1,142
M.O.C. #9808
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Quote:
quote:Originally posted by clutch
A good rule is to go down in the same gear you went up.
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Mike,
That is great advice. If you didn't drive up the hill and you see 6% or greater grade sign, slow down before you start down the hill. If it is freeway and no sharp corners I uses D with overdrive OFF. If there are 40-50 MPH corners, I use 2nd.
Last trip out I ran into a 11% grade, and dropped the speed down and put it in 1st at the start of the hill. RPM still got high and I had to hit the brakes to get RPM back down.
Most hills I go down, I never have to touch the brakes. If I do, I hit them hard enough to drop the RPM back down to 2,500, and then get off of them. Don't ride the brakes, if RPM is getting to high hit the brakes hard enough to drop the RPM back down and let the engine do the work.
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08-25-2010, 08:00 PM
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#6
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Montana Master
Join Date: Jul 2006
Location: Pasco
Posts: 986
M.O.C. #5972
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Are there shifting limits when you can go from drive to 2 or 2 to 1?
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08-26-2010, 04:27 PM
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#7
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Montana Fan
Join Date: Aug 2006
Location: cottam
Posts: 318
M.O.C. #6133
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do you know for sure that the pac brake is operating.they used to have problems with the butter fly would stick and needed oiling to keep it workin freely.if the butterfly stays open then it will not build up backpressure.this is what helps you slow down.
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08-30-2010, 07:40 PM
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#8
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Montana Master
Join Date: Jul 2006
Location: Pasco
Posts: 986
M.O.C. #5972
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I have heard it open and close. It seems to work, just not to the extent I think it should. I will see about oiling it however, just to make sure. It has been a year since I had it installed. I think I will test it tomorrow on the way to work. Even without the trailer it should work since I will be doing 70...just take my foot off the gas and see what happens.
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