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02-18-2012, 11:33 AM
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#1
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Senior Member
Trailer: Casita
Posts: 651
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What gear?
Since our trailers are on the light side I was wondering what mode of drive everyone uses to pull their units? Most TV's have that button to push for trailer hauling but I always thought it was more for the heavier trailers or hilly terrain. Regular overdrive mode is better mileage but it could be hard on the tranny under the right conditions.
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02-18-2012, 11:51 AM
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#2
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Senior Member
Trailer: 1996 Casita Freedom Deluxe 17 ft
Posts: 454
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I have always pulled my 17" Casita with my Ford Escape in regular overdrive. I let the transmission downshift itself when going up grades, which we have a lot of in Colorado. With most newer vehicles, there's enough stuff to protect you from damaging your rig. My TV transmission has a cooler and a temperature sensor. I would suggest that people change their transmission fluid when it's due.
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02-18-2012, 11:52 AM
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#3
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Senior Member
Name: Greg
Trailer: 72 Boler American
Indiana
Posts: 1,557
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As far as I can tell the tow/haul mode keeps you from using the overdrive feature, then that burns more gas, but they say if you don't use it that you can damage the transmission. That said is why I pull with a 5 speed manual transmission.
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02-18-2012, 12:44 PM
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#4
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Senior Member
Trailer: 2004 13 ft Scamp Custom Deluxe
Posts: 8,519
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Quote:
Originally Posted by Greg H
As far as I can tell the tow/haul mode keeps you from using the overdrive feature, then that burns more gas, but they say if you don't use it that you can damage the transmission. That said is why I pull with a 5 speed manual transmission.
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Bear in mind, that when towing in overdrive, in virtually every manual transmission, you exert more stress on the input and output shaft bearings, than if you tow in the 1/1 ratio gear(usually 4th, check your manual)
That said, I use overdrive consistently when pulling my little Scamp and shift when appropriate.
All my vehicles are manuals
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02-18-2012, 08:09 PM
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#5
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Senior Member
Name: Mike
Trailer: 2012 Escape 19
Oklahoma
Posts: 6,018
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My 17' Burro was only about 2400 lbs. loaded, but I used 4th gear rather than 5th on my automatic transmission. The problem with OD automatics is that they allow the tranny to slip too much when it's under some strain, and the tach will rise about 500 RPM. Locking out OD makes the RPMs go up about 1000 on mine, so I know the 500 rise is not a shift. That slippage increases friction in the tranny, which increases temperature. Higher temp is the enemy.
Floyd, I never knew that about the bearing stress. I always wondered. I guess at least the manual isn't going to build up temps from slippage like the automatic can, but it's nice to be aware that there is some downside.
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02-18-2012, 11:54 PM
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#6
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Moderator
Trailer: Fiber Stream 1978 / Honda Odyssey LX 2003
Posts: 8,222
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I towed in regular "Drive" (which is overdrive) all of the time in my 2003 Odyssey for the first 90,000 miles and then I had to replace the transmission. Yes, I had both the transmission cooler and the power steering cooler installed from the beginning. I also had the transmission recall repair done. It was very expensive ($5000 at the dealer with a 50,000 mile warranty) but much less than the $30,000 for a new 2010 Odyssey. It has 120,000 miles on it now, and I drop to D3 when climbing hills.
__________________
Frederick - The Scaleman
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02-19-2012, 02:14 AM
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#7
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Senior Member
Name: Dave
Trailer: ,Bigfoot 25 foot plus Surfside 14 foot
British Columbia
Posts: 1,148
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Mike - I suspect that when your tach climbs by 500 RPM or so, it is the "lock-up" torque converter unlocking. The next RPM jump is actually the trans going down one gear.
If you manually shift down, you are unlocking the torque converter anyway. Very few can run with the T/C locked if you are in any gear other than the highest one available.
Running with it unlocked creates huge amounts of heat. Heat destroys auto transmissions. The ones with Tow/Haul mode have the ability to either run unlocked all the time when that is selected or the ability to go down a gear while staying locked up.
For those who actually care about getting their money's worth out of a vehicle, there are some gauges / instruments you should have.
If your vehicle does not already have these - consider getting them
Volt meter
Oil Pressure ga
temp ga
transmission temp ga
vacuum ga.
Tachometer
The lower the trans temp the longer your (horribly expen$ive) trans will live.
The higher the vacuum reading the better the fuel economy
On my truck, I just put it in O/D. The trans will unlock the T/C, and then downshift if needed. However, remember that mine has a humongous super duty (4L80E Series) trans. Lighter duty ones found in lighter duty trucks are not as robust. (Ask me about blowing up 2 transmissions in one day using a lighter-duty truck for the sort of stuff that "Babe the Blue Ox" does on a regular basis!)
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02-19-2012, 02:24 AM
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#8
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Senior Member
Name: Bill
Trailer: Lil Snoozy / Jeep Cherokee
Pennsylvania
Posts: 401
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Bearing Stress?
I never thought much about "bearing stress" as Floyd points out. But, practically thinking, he is correct. However, I don't see bearing stress as a factor when cruising in overdrive in a no strain on your engine situation and down shifting as soon as the need arises. I, too, have always had manual transmissions as I have never been able to adjust to having a vehicle that shifts when it wants to rather than when I want it to. Saying this, I do know that some automatics are pretty good at shifting when they need to. I have even raced against some competitors that found advantages to road racing with automatics while showing me the backs of their race cars.
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02-19-2012, 10:03 AM
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#9
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Senior Member
Trailer: 2004 13 ft Scamp Custom Deluxe
Posts: 8,519
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Quote:
Originally Posted by Bill in Pittsburgh
I never thought much about "bearing stress" as Floyd points out. But, practically thinking, he is correct. However, I don't see bearing stress as a factor when cruising in overdrive in a no strain on your engine situation and down shifting as soon as the need arises. I, too, have always had manual transmissions as I have never been able to adjust to having a vehicle that shifts when it wants to rather than when I want it to. Saying this, I do know that some automatics are pretty good at shifting when they need to. I have even raced against some competitors that found advantages to road racing with automatics while showing me the backs of their race cars.
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As we get ever closer to "auto pilot", I am sure that we will see the complete elimination of manual transmissions. Heck...computers may even refuse to tow at some point, unless allowed by the manufacturer.
As for road racing....too many factors to give any advantage credit to automatics,like ABS and traction control,they are just poor substitutes for driver skills IMHO.
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02-19-2012, 10:14 AM
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#10
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Senior Member
Name: Jon
Trailer: Escape 21C
New York
Posts: 2,387
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I follow Toyota's manual for my RAV4 & Escape 17B - Tow in 4th (locks out overdrive). The few times I have tried in 5th it shifts far too often.
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02-19-2012, 10:18 AM
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#11
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Senior Member
Name: Bill
Trailer: Lil Snoozy / Jeep Cherokee
Pennsylvania
Posts: 401
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One other point
I think the reason that it is a good idea to not tow in overdrive mode with an automatic is to eliminate the frequent shifting your transmission would be required to do. Almost every type of machinery as a finite life cycle, and every shift puts it one step closer to the end of that cycle (not to mention factors such as heat and others).
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02-19-2012, 12:43 PM
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#12
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Senior Member
Name: Mike
Trailer: 2012 Escape 19
Oklahoma
Posts: 6,018
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BCDave, I believe you're right about it being the torque converter unlocking and letting the RPMs rise about 500. I'm no mechanic by any means, but when the torque converter unlocks is that allowing some sort of increased slippage in the transmission? That's how I interpreted some explanations I'd read in the past.
When OD is locked out by moving the shift lever to the next lower gear, however, I don't think the converter is unlocked. The reason I say that is, my RPMs don't ever do that halfway climb to the next gear... ever. If called for, the transmission will shift down further, but it will not do that halfway RPM thing that it does in OD. I figure the converter locks again and stays locked, at least until it calls for a full shift. What do you think?
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02-19-2012, 01:05 PM
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#13
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Senior Member
Name: Dave
Trailer: ,Bigfoot 25 foot plus Surfside 14 foot
British Columbia
Posts: 1,148
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Quote:
Originally Posted by Mike Magee
BCDave, I believe you're right about it being the torque converter unlocking and letting the RPMs rise about 500. I'm no mechanic by any means, but when the torque converter unlocks is that allowing some sort of increased slippage in the transmission? That's how I interpreted some explanations I'd read in the past.
When OD is locked out by moving the shift lever to the next lower gear, however, I don't think the converter is unlocked. The reason I say that is, my RPMs don't ever do that halfway climb to the next gear... ever. If called for, the transmission will shift down further, but it will not do that halfway RPM thing that it does in OD. I figure the converter locks again and stays locked, at least until it calls for a full shift. What do you think?
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Its not the trans that is slipping when the T/C is unlocked - it is t/c itself that now slips.
If you shift down out of O/D, it will be unlocked all the time, so moving the lever down to D (from O/D) you get the full "down one gear PLUS unlocked" effect. It will only lock in the highest gear, so unless you are in O/D, it cannot do the 400 or 500 RPM thing.
However - if you are NOT in O/D, and you lightly step on and off the gas pedal a couple of times (without actually changing speed of the vehicle), you will likely get a "bounce' in RPM of the same amount as you put "tension" on it and then back off. Adding gas brings it up to its max slip, while getting off the gas shows what the rpm would be if it was locked.
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02-19-2012, 01:14 PM
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#14
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Senior Member
Name: Andrew
Trailer: Modified Trillium Jubilee
Ontario
Posts: 240
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I keep my eye on the RPMs and speedometer. It's easy to tell when the torque converter is locked. To save the transmission, the best is to run it at a speed and gear that keeps the TC locked . For my Rainier, it means D when on flat without significant head wind. 3rd when climbing hills so; I often manually downshift when approaching a hill so the TC stays locked virtually all the time. On steep hills, sometimes I go down to 2nd. Modern engines can spin fast without any harm but running for a length of time with TC slipping will wear out the transmission faster. AFAIK TCs main purpose is to allow for smooth shifting and not for efficiency.
To be clear; From my experience, Rainier can lock the TC in 2nd, 3rd and D. Can't tell in 1st. because I never use it.
__________________
I wish to be one day at least half as good as I think I am today. Andrew Kalinowski
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02-19-2012, 02:43 PM
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#15
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Senior Member
Name: Mike
Trailer: 2012 Escape 19
Oklahoma
Posts: 6,018
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Quote:
Originally Posted by BCDave
Its not the trans that is slipping when the T/C is unlocked - it is t/c itself that now slips.
If you shift down out of O/D, it will be unlocked all the time, so moving the lever down to D (from O/D) you get the full "down one gear PLUS unlocked" effect. It will only lock in the highest gear, so unless you are in O/D, it cannot do the 400 or 500 RPM thing.
However - if you are NOT in O/D, and you lightly step on and off the gas pedal a couple of times (without actually changing speed of the vehicle), you will likely get a "bounce' in RPM of the same amount as you put "tension" on it and then back off. Adding gas brings it up to its max slip, while getting off the gas shows what the rpm would be if it was locked.
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I don't get that RPM 'bounce', though. So maybe mine is locked up in 4th. We both got a PM from another member who said his Sienna's converter is locked up in 4th as well as 5th.
Thanks for clarifying about what is slipping and what's not. I'm never too old to learn something.
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02-19-2012, 03:07 PM
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#16
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Senior Member
Name: Dave
Trailer: ,Bigfoot 25 foot plus Surfside 14 foot
British Columbia
Posts: 1,148
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I was not aware that some systems can lock up the T/C in gears other than highest - but then to me a 'new" vehicle is anything newer than the 1990's!
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02-19-2012, 03:19 PM
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#17
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Senior Member
Name: Jesse
Trailer: 1984 Scamp 13'
Maryland
Posts: 815
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Quote:
Originally Posted by BCDave
I was not aware that some systems can lock up the T/C in gears other than highest - but then to me a 'new" vehicle is anything newer than the 1990's!
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My TC locks up at about 15 MPH and stays locked through all gears. Well, I don't really have gears, but the TC stays locked until the car slows to only 10 MPH or so, then unlocks. Newfangled technology!
__________________
-Jesse
SOLD! - 1984 Scamp 13 in Maryland.
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02-19-2012, 03:27 PM
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#18
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Senior Member
Trailer: No Trailer Yet
Posts: 5,112
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Quote:
Originally Posted by BCDave
I was not aware that some systems can lock up the T/C in gears other than highest - but then to me a 'new" vehicle is anything newer than the 1990's!
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Automatic transmissions have changed a lot in the past 10 years in the quest for greater fuel economy. More lock up, more gears.
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