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Re: Manual Shifting Allison

Reply #25 –
Quote from: gootie –
In the mountains getting coolant flow increase with a selection of a lower gear on the uphill will aid in keeping temps reasonable. Coming down intermittent app of retard will run tranny temp up but if already in a lower gear will also expedite tranny temp reduction. I miss my coach


Excellent point.  When descending long grades with a transmission retarder, you will keep transmission temps in check by staying at the high end of engine RPM, as that spins the water pump faster.

A LONG time ago, I was in Skagway, AK when a Foretravel Caravan came into town.  A couple of extremely overheated transmission.  Evidently, the wagon master did not review this before the incredible descent of the Chilkoot pass.
Brett Wolfe
EX: 1993 U240
Moderator, ForeForum 2001-
Moderator Diesel RV Club 2002-
Moderator, FMCA Forum 2009-2020
Chairman FMCA Technical Advisory Committee 2011-2020

Re: Manual Shifting Allison

Reply #26 –
Quote from: gootie link=msg=269851 date=1493413390  I miss my coach[/quote

And well you should!  :))  Every year, with SOB coaches, pulling I-17 from Phoenix to Flagstaff  (prolly 6k pull) was daunting. With this coach, she just does what she wants to do, I don't fool with the Allison at all, and once the retarder is engaged on drops, I don't do much either. I do keep a close eye on the gauges, though.
1993 U-240 "La Villa Grande"..CAT 3116 w/ Pacbrake PRXB...Allison 3060 6-speed..
Previous: 1983 Airstream 310 turbo diesel, 1979 Airstream 280 turbo diesel
                                      Build # 4297
                                      PNW natives
                      Home base:  'Cactus Hug' (Ajo, Arizona)
                        DW Judy & Chet the wonder dog
                        Full-Timers 'Sailing the asphalt sea'

Re: Manual Shifting Allison

Reply #27 –
I know the peak torque on my M-11 is 1500rpm.  If the tach drops below 1300 climbing I start downshifting.  Coming downhill, if I see a sign for 6% or steeper grade, I downshift to 4th at the top.  If my retarder is not keeping my speed in check, I brake firmly and shift to 3rd, repeating as needed.
Regards,
Brett

'99 42' Foretravel Xtreme
'14 Brown Motorsports Stacker
'05 Chevy SSR
'02 BMW R1150R

Re: Manual Shifting Allison

Reply #28 –
Quote from: amos.harrison –
I know the peak torque on my M-11 is 1500rpm.  If the tach drops below 1300 climbing I start downshifting.  Coming downhill, if I see a sign for 6% or steeper grade, I downshift to 4th at the top.  If my retarder is not keeping my speed in check, I brake firmly and shift to 3rd, repeating as needed.
I believe our peak torque is at 1200 rpm.
1999 40 ft. U-320 wtfe build 5563 Chuck & Lynda's "Rollin' Inn"  2030 watts solar
prev. mh's 71 GMC 5 yrs. 73 Pace Setter 1 yr. 78 Vogue 5 yrs 81 FTX 40ft all electric 18 yrs. 1996 Monaco Signature 3 yrs.
2014 Grand Cherokee Overland
Dream as if you will live forever. Live as if you will die today.  James Dean

Re: Manual Shifting Allison

Reply #29 –
1350-1400 if memory serves me.  Fat torque curve about there. Hp going up at that point.

"Riding and rejoicing"
Bob
1997 U320 40' Mid entry, build 5132,  wtbi ce27, 4th owner
2007 Solara convertible
2 prodeco tech outlaw ss electric bikes

1095 watts solar
08 Ls 460 and a sc430
2000 Ford F-250 superduty 4x4

Re: Manual Shifting Allison

Reply #30 –
1200 across the board
Cummins M Series engine - Wikipedia
1999 40 ft. U-320 wtfe build 5563 Chuck & Lynda's "Rollin' Inn"  2030 watts solar
prev. mh's 71 GMC 5 yrs. 73 Pace Setter 1 yr. 78 Vogue 5 yrs 81 FTX 40ft all electric 18 yrs. 1996 Monaco Signature 3 yrs.
2014 Grand Cherokee Overland
Dream as if you will live forever. Live as if you will die today.  James Dean

Re: Manual Shifting Allison

Reply #31 –
We have all noticed the ability to pull grades seems to be as good or better at 1400-1500 rpm.

Flite10(bob) and I talked about this today.  We both noticed it on our 97 m11 celect plus engines. 

If that'past the torque peak on a chart which is fairly flat at those rpms then the rising hp curve must work with the torque at those rpms.

The additional power seems to allow somewhat higher road speeds without a mpg loss.

That being said we both have the dynamatic 199 degree hydraulic fan controllers and aero 5050xl resonators.

He showed me on his glass dash his run into Orange County towing a dolly at 63-64 mph and the VPMS showed 10.2 mpg.

That's when he mentioned the better hill climbing over the nominal 1200 rpm rating.

Amos Harrison is saying the same thing.

Running hard in wind to Vegas and back at 37,000 pounds I averaged 8.2 mpg at 70 minimum and downshifting on all grades and revving the motor up. 



"Riding and rejoicing"
Bob
1997 U320 40' Mid entry, build 5132,  wtbi ce27, 4th owner
2007 Solara convertible
2 prodeco tech outlaw ss electric bikes

1095 watts solar
08 Ls 460 and a sc430
2000 Ford F-250 superduty 4x4

Re: Manual Shifting Allison

Reply #32 –
For the Alaska pass I actually thought about a Jake brake for my m11.

I think both the retarder and Jake could be on at the same time if wired that way. 

I had  to try hard to get the trans buzzer to come for testing purposes.

Full speed downhill at grapevine ca.  And again at monarch pass. 

Trans Buzzer on at 250.  Bottom of grade and two miles with retarder off the buzzer ceased.



"Riding and rejoicing"
Bob
1997 U320 40' Mid entry, build 5132,  wtbi ce27, 4th owner
2007 Solara convertible
2 prodeco tech outlaw ss electric bikes

1095 watts solar
08 Ls 460 and a sc430
2000 Ford F-250 superduty 4x4

Re: Manual Shifting Allison

Reply #33 –
For extreme grades (length as well as steepness) like descending into Skagway Alaska, down arrow to a low gear--perhaps even second gear and use the least amount of retarder that you can. Keep engine RPM near the high-end of the RPM range so the water pump turns faster.

If transmission temperature becomes excessive use a pull-out (there are several on that particular road-- we have driven it several times).
Brett Wolfe
EX: 1993 U240
Moderator, ForeForum 2001-
Moderator Diesel RV Club 2002-
Moderator, FMCA Forum 2009-2020
Chairman FMCA Technical Advisory Committee 2011-2020

Re: Manual Shifting Allison

Reply #34 –
Yes on what Wolfe10 said.  Definitely lowered the trans temp from less load and higher coolant speed
"Riding and rejoicing"
Bob
1997 U320 40' Mid entry, build 5132,  wtbi ce27, 4th owner
2007 Solara convertible
2 prodeco tech outlaw ss electric bikes

1095 watts solar
08 Ls 460 and a sc430
2000 Ford F-250 superduty 4x4

Re: Manual Shifting Allison

Reply #35 –
When climbing, the rule is:  if the coach will not accelerate with more go pedal, you are in too high a gear-downshift.  My engine will bog down at 1200rpm.
Regards,
Brett

'99 42' Foretravel Xtreme
'14 Brown Motorsports Stacker
'05 Chevy SSR
'02 BMW R1150R

Re: Manual Shifting Allison

Reply #36 –
Quote from: amos.harrison –
When climbing, the rule is:  if the coach will not accelerate with more go pedal, you are in too high a gear-downshift. 

Good rule-- I agree.
Brett Wolfe
EX: 1993 U240
Moderator, ForeForum 2001-
Moderator Diesel RV Club 2002-
Moderator, FMCA Forum 2009-2020
Chairman FMCA Technical Advisory Committee 2011-2020

Re: Manual Shifting Allison

Reply #37 –
To add to Brett, it seems like pressing accelerator without increased RPM, indicates fuel being added could cause engine to run hotter with no gain in power.  We never have throttle pedal to the floor.  It take patience to let up on throttle when the heart says press harder on throttle.

Re: Manual Shifting Allison

Reply #38 –
Quote from: Barry & Cindy –
To add to Brett, it seems like pressing accelerator without increased RPM, indicates fuel being added could cause engine to run hotter with no gain in power.  We never have throttle pedal to the floor.  It take patience to let up on throttle when the heart says press harder on throttle.
The electronic engines control the fuel with sensors so there is no worry about EGTs as the Allison will downshift on it's own. Still a good idea to keep RPMs up to circulate coolant. That's why you don't see any black smoke out the exhaust. With the mechanical engines, back off the throttle when you see smoke in the mirror as that can raise EGTs especially up at altitude plus is rude to cars behind.

I am almost always throttle to the floor off stop signs, on ramps, hills, etc. When I reach the speed I want to drive at, then I back off. Sensors/ECU keep it smoke free. On grades, if it won't accelerate or starts slowing down, it's time to manually shift down a gear. 200 degrees makes me ease up on the throttle and drop a gear. Back roads with a lot of turns also make me treat the tranny like a manual so I do most of the shifting. Heading steep downgrades on two lane roads also sees me using the touch pad, service brakes and Jake. Interstate downgrades are usually high gear, Jake only with few exceptions.

Pierce
Pierce and Gaylie Stewart
'93 U300/36 WTBI
Detroit 6V-92TA Jake
1140 watts on the roof
SBFD (ret)

Re: Manual Shifting Allison

Reply #39 –
I've always heard this: Torque gets you up to speed, HP helps keep you at that speed.
Jerry & Nona and Kimeru the cat that thinks she's a dog
1998 36' WTFE U320  #5314 Motorcade #17711
USAF 1975-1995
2019 Subaru Crosstrek 'toad'
2003 Subaru Legacy touring car
jerry Fincher | Flickr

Re: Manual Shifting Allison

Reply #40 –
I always thought it was the other way around................
HP to accelerate and torque to keep you at speed...................
Justin & Cathy Byrd
1995 U280 "Old Faithful"
36' Build #4673
C8.3 Cummins
Allison MD3060R 6 speed - retarder
Powertech 10KW  4cyl Kubota

Re: Manual Shifting Allison

Reply #41 –
You are probably both right....I knew I liked more of each! 😀
Mike
2001 U320 4010 Build 5878 (Gus)
Wrangle Unlimited Toad
Nacogdoches

Re: Manual Shifting Allison

Reply #42 –
Bigdog has it correct, the horsepower rating does not come in until much higher rpm. When driving up a grade engines like to be at or above the max torque rpm. Think of torque, launches you, and HP keeps the acceleration going after you pass the peak torque rpm.
1999 40 ft. U-320 wtfe build 5563 Chuck & Lynda's "Rollin' Inn"  2030 watts solar
prev. mh's 71 GMC 5 yrs. 73 Pace Setter 1 yr. 78 Vogue 5 yrs 81 FTX 40ft all electric 18 yrs. 1996 Monaco Signature 3 yrs.
2014 Grand Cherokee Overland
Dream as if you will live forever. Live as if you will die today.  James Dean

Re: Manual Shifting Allison

Reply #43 –
Some engines are mph faster up grades short shifted using the torque.  Most are slightly faster using the hp at high rpms.

Our m11 is around five mph faster up grades revved hard than upshifted to use the torque.

I have driven coaches where the torque is faster than the revved hp.
"Riding and rejoicing"
Bob
1997 U320 40' Mid entry, build 5132,  wtbi ce27, 4th owner
2007 Solara convertible
2 prodeco tech outlaw ss electric bikes

1095 watts solar
08 Ls 460 and a sc430
2000 Ford F-250 superduty 4x4