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02-04-2025, 01:08 PM
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#15
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Senior Member
Join Date: Oct 2002
Location: Madison, MS
Posts: 10,559
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Quote:
Originally Posted by yeloduster
Ultra RV offers a grade brake modification for 2001 to 2003 W series chassis with the Allison 1000 transmission.
Click on ULTR RV GRADE BRAKE. I'm sure it works great.
Do you need a grade brake? Nope! Would it be nice...maybe!
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YES, that's it. In addition to the website link, there is a step by step installation done by DriVer up in the stickies at the top of this forum.
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02-05-2025, 10:24 AM
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#16
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Senior Member
Monaco Owners Club
Join Date: Jan 2011
Location: Rio Rancho, NM
Posts: 190
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We have the aforementioned grade brake feature on our coach with Allison 2K series tranny. Although we live 30 minutes NW of Albuquerque and all RVing whether coming or going requires traveling mountain roadways, we primarily use grade brake only on the steepest of declines.
As the vast majority of our RVing adventures take place in the four corner states at high elevations, we most often have overdrive switch off and only engage grade brake switch as outlined above. Grade brake is nice feature but is can be overly aggressive at times.
After RVing for 3+ decades in long travel trailers and fifth wheels with our kids, and now with our current 40' motorcoach utilizing mountain roadways, I prefer to manually handle the downshifting/upshifting required to get back and forth safely in our neck of the woods.
We engage overdrive switch when traveling on the flatlands in TX and eastward, and the lower elevation deserts of AZ, CA, and NV. With overdrive off we don't get into 5th gear but the added grunt helps getting through the many high elevation inclines we regularly face.
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Today, 11:08 AM
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#17
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Member
Join Date: Aug 2005
Location: Sacramento, CA
Posts: 39
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Downshifting is ok but the rpms climb and climb and speed will continue to increase out of control. It's my understanding the TGB hold the rpm's and maintains speed going downhill.
I'm researching the Ultrapower TGB to purchase to do such a thing.
I have a 2004 and the only way I have been able to keep speeds low on downhills is to put the transmission in 2nd gear to hold 25mph max. This works on steep descents (like hwy 50 into Tahoe or into Yosemite) but doesn't work with freeway speeds. Freeway speed steep descents (like hwy 80 into Truckee) it will not maintain any speed and will run-away without constant braking.
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Today, 11:16 AM
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#18
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Senior Member
Join Date: Nov 2018
Location: Fulda, MN
Posts: 1,849
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From my understanding, it downshifts every time you step on the brake pedal. If it senses that the engine will overrev then it does not. I do not drive in the mountains, just our 3% half mile long "mountains" here.
__________________
2000 Winnebago Adventurer 32v, P32 Workhorse
2005 Winnebago Adventurer 38J W24 Workhorse 8.1l, 5 Speed Allison MH2000
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Today, 03:53 PM
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#19
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Senior Member
Workhorse Chassis Owner
Join Date: Sep 2017
Posts: 2,461
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Quote:
Originally Posted by y2kbaja
Downshifting is ok but the rpms climb and climb and speed will continue to increase out of control. It's my understanding the TGB hold the rpm's and maintains speed going downhill.
I'm researching the Ultrapower TGB to purchase to do such a thing.
I have a 2004 and the only way I have been able to keep speeds low on downhills is to put the transmission in 2nd gear to hold 25mph max. This works on steep descents (like hwy 50 into Tahoe or into Yosemite) but doesn't work with freeway speeds. Freeway speed steep descents (like hwy 80 into Truckee) it will not maintain any speed and will run-away without constant braking.
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The Ultrapower TGB does essentially the same thing as downshifting. If your initial speed is too fast and or the grade too steep engine speed will increase. The transmission/engine computers will not allow the engine RPMs to get too high. The transmission will shift into a higher gear to protect the engine. In either case the operator, that would be you, has the responsibility to assure that doesn't happen by starting the grade at a slower speed and use the brake pedal as required.
You said, "Freeway speed steep descents." If by that you mean traveling at the speed limit or even 60 MPH you are driving too fast! Most interstate highways have a maximum grade of 6-7%. The max safe speed for your motorhome on a 6% down grade is about 45 MPH. For instance, I descend I70 into Denver from the west at ≈45 MPH in second gear with RPMs ≈4000. I seldom need to touch the brake. I manually shift. The Ultrapower TGB does the same thing as I do except the shifting is automatic...unless you are going too fast. If you are going too fast the transmission will never downshift by using the shift lever OR using Ultrapower TGB. It will not let you go down a 6% grade at 60 MPH without using the brake A LOT!
The Ultrapower TGB is not magic. It is just a more convenient.
__________________
2003 34' Georgetown on W20 Workhorse Chassis. UltraRV power mods. Doug Thorley Headers and MagnaFlow 12589 mufflers. Front Sumo Springs, Rear P32 Sumo Springs, UltraRV Track Bar.
1998 Jeep Toad.
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Today, 03:58 PM
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#20
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Member
Join Date: Aug 2005
Location: Sacramento, CA
Posts: 39
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Quote:
Originally Posted by yeloduster
The Ultrapower TGB does essentially the same thing as downshifting. If your initial speed is too fast and or the grade too steep engine speed will increase. The transmission/engine computers will not allow the engine RPMs to get too high. The transmission will shift into a higher gear to protect the engine. In either case the operator, that would be you, has the responsibility to assure that doesn't happen by starting the grade at a slower speed and use the brake pedal as required.
You said, "Freeway speed steep descents." If by that you mean traveling at the speed limit or even 60 MPH you are driving too fast! Most interstate highways have a maximum grade of 6-7%. The max safe speed for your motorhome on a 6% down grade is about 45 MPH. For instance, I descend I70 into Denver from the west at ≈45 MPH in second gear with RPMs ≈4000. I seldom need to touch the brake. I manually shift. The Ultrapower TGB does the same thing as I do except the shifting is automatic...unless you are going too fast. If you are going too fast the transmission will never downshift by using the shift lever OR using Ultrapower TGB. It will not let you go down a 6% grade at 60 MPH without using the brake A LOT!
The Ultrapower TGB is not magic. It is just a more convenient.
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Copy, not a magic wand. My issue is I crest the summit at 35, downshift to 3rd, proceed down the hill, and within 1/4 mile I'm doing 60 with the engine at 4,000-rpms. This is pulling the towd. Yes; brake, slow to 35-40, release brake, and back to 60.
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