โDec-02-2017 07:24 AM
โDec-17-2017 02:06 PM
โDec-17-2017 12:38 PM
โDec-17-2017 11:56 AM
โDec-17-2017 10:59 AM
Ductape wrote:
But that's exactly the point. You ended up in KOA... Thanks but no thanks. ๐
โDec-17-2017 09:59 AM
โDec-17-2017 07:01 AM
โDec-17-2017 12:05 AM
gutfelt wrote:msturtz wrote:
I'm running a 2014 Thor Palazzo 33.3. It has a ISB 300 and Allison 2100 MH. I could go to ISB 340 / 700 with the same transmission. I have towed a 2015 Suburban, 2015 GMC Acadia Denali, 2016 Yukon Denali XL, and 2017 Ford Explorer. The I am at my max GCWR when I tow the Yukon and the motor home is empty. The transmission does downshift. I have traveled over the rocky mountains 4 times with this setup (pulling the Acadia) we had no problems. I probably will upgrade to ISB 340.
A suburban weighs more than a 2015 yucon or explorer
โDec-16-2017 04:04 PM
โDec-16-2017 01:14 PM
โDec-16-2017 12:07 PM
โDec-16-2017 08:25 AM
Ductape wrote:
Backstory- we're in the market for a short coach, less than 36 feet. It's our preference (due to the types of parks we enjoy). Likely a Newmar Ventana or Ventana LE or Tiffen RED. We'll pull a large toad. Perhaps new, but we'll also consider going back a few years, but not before DEF engines.
I dislike a powertrain that's maxed out on torque and has to shift gears too often. Defeats the whole purpose of a diesel so to speak. And I've operated some trucks like that.
The real technical stuff: Most coaches in this range are built with the Allison 2000 series trans, a few have the 3000 Allison. The smaller transmission has limited torque handling capability and is used with the ISB 300 or 340, with peak torque ratings of 600 to 700. The Allison 3000 enables use of the ISB 360 which is 800 lb-ft torque. Which seems like not much difference, right?
But here's the thing; the 2000 series requires the use of torque managed engines, which limit the torque when shifting (not a bad thing) and also the torque in certain gears (and this is my concern). The 2000 series trans allows up to 700 lb-ft in gears 3-5. In other conditions it's limited to 575 lb-ft. Limitations on the Allison 3000 are not a concern with the ISB, as the trans can handle 1250 lb-ft and torque management is not required.
So... it would appear that the ISB360/Allison 3000 combo can draw on all 800 lb-ft of torque to maintain speed on a grade in any gear, whereas the ISB340/Allison 2500 by comparison can only use 575 lb-ft in 6th gear. That sounds like a recipe for easily dropping out of 6th with the smaller transmission. But does the real world experience match?
Thanks for your patience in reading my dissertation, and I appreciate your feedback.
โDec-16-2017 05:09 AM
โDec-04-2017 06:22 PM
โDec-04-2017 06:07 PM