kdl Posted October 7, 2009 Share Posted October 7, 2009 I have read different topics on overdrive and still don't quite understand it. Do you put your rv in overdrive going up a hill, I usually put it in second when slows to 45 going up hills. Do you put it in od on a flat road. I don't understand od so am afraid to use it so as not to ruin my motor. Maybe if I understood what od does I can make an informative decision about using it. Thanks, am getting better at driving the rv, but certainly could use some tips in driving, if anyone can give me any tips driving such a heavy rv with a little motor. Quote Link to comment Share on other sites More sharing options...
WME Posted October 7, 2009 Share Posted October 7, 2009 Don't worry how it works, just DON'T use it EVER. Quote Link to comment Share on other sites More sharing options...
powdrhound Posted October 7, 2009 Share Posted October 7, 2009 It is amazing how much less I use overdrive since I installed the transmission temp gauge. At freeway speed when I activate the OD I will see the transmission gain at least 30 degrees. Downshift, and I can watch it drop. When I first installed the gauge, my 'normal' driving habits were putting the oil at above 310 degrees (on the freeway with a headwind). Everything I can find says that the trans fluid is damaged above 200 degrees. That is when I replaced the little trans cooler with the largest one I could pack in. That alone dropped the temps 30 degrees under all conditions. I may even re-install the old one for double cooling. At 55 mph in 3rd, I am clocking about 3,000 RPM. Since the power curve drops off dramatically below 2,500 RPM, shifting to OD will drop it ~ 1,000 RPM, well below the power curve. The motor may be turning slower, but it is lugging and my foot is closer to the floor. Even at 65 mph, the motor is purring ~ 3,400. I now use OD only when going downhill with the wind at my back. (Tho I still want to disable the altitude switch.) John ps. The first snow of the season for the Sierra's this weekend. Looked beautiful on the mountain tops. Bring it ON! Quote Link to comment Share on other sites More sharing options...
kdl Posted October 9, 2009 Author Share Posted October 9, 2009 It is amazing how much less I use overdrive since I installed the transmission temp gauge. At freeway speed when I activate the OD I will see the transmission gain at least 30 degrees. Downshift, and I can watch it drop. When I first installed the gauge, my 'normal' driving habits were putting the oil at above 310 degrees (on the freeway with a headwind). Everything I can find says that the trans fluid is damaged above 200 degrees. That is when I replaced the little trans cooler with the largest one I could pack in. That alone dropped the temps 30 degrees under all conditions. I may even re-install the old one for double cooling. At 55 mph in 3rd, I am clocking about 3,000 RPM. Since the power curve drops off dramatically below 2,500 RPM, shifting to OD will drop it ~ 1,000 RPM, well below the power curve. The motor may be turning slower, but it is lugging and my foot is closer to the floor. Even at 65 mph, the motor is purring ~ 3,400. I now use OD only when going downhill with the wind at my back. (Tho I still want to disable the altitude switch.) John ps. The first snow of the season for the Sierra's this weekend. Looked beautiful on the mountain tops. Bring it ON! thank you both for the reply, it seems I was correct in thinking just not to use it since I know not what i'm doing. I find it slow going up hills but I seem to have it down as to handle the motor on hills. Quote Link to comment Share on other sites More sharing options...
AJK Posted January 28, 2010 Share Posted January 28, 2010 Altitude Switch! WHere is it and why shouldn't it be disabled? We just got an '86 Dolphin and are having trouble getting to know it's quirks - and basics about RV life as well! It is amazing how much less I use overdrive since I installed the transmission temp gauge. At freeway speed when I activate the OD I will see the transmission gain at least 30 degrees. Downshift, and I can watch it drop. When I first installed the gauge, my 'normal' driving habits were putting the oil at above 310 degrees (on the freeway with a headwind). Everything I can find says that the trans fluid is damaged above 200 degrees. That is when I replaced the little trans cooler with the largest one I could pack in. That alone dropped the temps 30 degrees under all conditions. I may even re-install the old one for double cooling. At 55 mph in 3rd, I am clocking about 3,000 RPM. Since the power curve drops off dramatically below 2,500 RPM, shifting to OD will drop it ~ 1,000 RPM, well below the power curve. The motor may be turning slower, but it is lugging and my foot is closer to the floor. Even at 65 mph, the motor is purring ~ 3,400. I now use OD only when going downhill with the wind at my back. (Tho I still want to disable the altitude switch.) John ps. The first snow of the season for the Sierra's this weekend. Looked beautiful on the mountain tops. Bring it ON! Quote Link to comment Share on other sites More sharing options...
bufbooth Posted January 29, 2010 Share Posted January 29, 2010 I use the OD on flat road and seems to work great for me, I have a V6 if that matters. As long as the road is flat, the OD kicks in at about 50mph and will stay in OD even up to 65mph. I usually turn off the OD if any hills are involved to keep the transmission from shifting up and down too often. Dennis... Quote Link to comment Share on other sites More sharing options...
Maineah Posted January 29, 2010 Share Posted January 29, 2010 I agree with Dennis I can't stand to hear the engine wound up for no reason when it's so easy to use O/D. Change (flush) the fluid every 30K use synthetic put on a big cooler and drive on. Will I get 100K out of mine using O/D? Probably. Will you get 100K out of yours not using O/D? Probably. Quote Link to comment Share on other sites More sharing options...
WME Posted January 30, 2010 Share Posted January 30, 2010 The V-6s have a lockup converter so they don't suffer from the heat problem. I live at 6000ft so my O/D has never worked and I don't miss it. Think of things this way. In 3rd gear the automatic has a 1:1 ratio. In the billion or so of the older Toy trucks with a 4 sp, 4th is also a 1:1 ratio. Those trucks have done just fine running in 4th gear for 200,000-300,000 mi at 65-70 mph Quote Link to comment Share on other sites More sharing options...
Gulfstream Greg Posted January 30, 2010 Share Posted January 30, 2010 There might be some confusion about overdrive. Remember we are talking about two different beasts, the tranny behind a R22 4 cylinder and the tranny behind a V6. As far as I know there is one big difference between the two. The 4 cyl does not have a locking torque converter and the V6 does have a locking torque converter. What does this mean? When the V6 is put into over drive the torque converter locks and does not slip and as a result does not create any friction generated heat. The 4 cyl does not lock and when in over drive continues to slip creating that deadly heat. Also the V6 tranny torque converter will lock when the transmission is in drive and in 3rd or 2nd gear. It will not lock if the transmission is placed in second gear manually. I use over drive all the time with our V6. I have the temp gauge sitting on a shelf waiting to install. But my past experience with a V6 transmission and a temp gauge showed that if I could get up to 60 mph and drop it into over drive I could actually watch the temperature fall. Where I found the highest heat generated was on curvy twisty roads where I was on and off the gas constantly. That was with a A340H transmission that is behind the 4x4 V6 and 22R Turbo engines. I would be interested to hear about some similar testing with the V6 models and a temp gauge. Quote Link to comment Share on other sites More sharing options...
Maineah Posted January 30, 2010 Share Posted January 30, 2010 The lock up is a big plus no doubt both in heat and fuel economy and with a 6 it will work. The 4 does not have the power (plus the age factor, not new enough for the technology) all converters do act as torque amplifiers to some extent (if they are not in lockup) and the 4 needs that. Converter slip is what causes the heat no doubt about it but driven in a sensible manner you can reduce the converter slip, slower speeds, lower gear on the hills and don't try to keep it to the floor. Generally the trans will down shift if it's working too hard that should be the first clue to shift it out of O/D until things improve. IMHO if you take care of the transmission even with using O/D it will last a long time. Quote Link to comment Share on other sites More sharing options...
Maineah Posted January 30, 2010 Share Posted January 30, 2010 The V-6s have a lockup converter so they don't suffer from the heat problem. I live at 6000ft so my O/D has never worked and I don't miss it. Think of things this way. In 3rd gear the automatic has a 1:1 ratio. In the billion or so of the older Toy trucks with a 4 sp, 4th is also a 1:1 ratio. Those trucks have done just fine running in 4th gear for 200,000-300,000 mi at 65-70 mph Agreed. But newer 22RE's have O/D 5 speeds they are quieter, use less fuel and run just as long. Quote Link to comment Share on other sites More sharing options...
centralman Posted February 2, 2010 Share Posted February 2, 2010 Hi everyone in the past Christmas I took my 87 Dolphin MH from Vancouver down to Los Angeles. If you are familiar with Interstate 5, you know when going down there you need to pass 2 summits one on the border of Oregon/California and the other just before Los Angeles. Those summits are 4,000 plus feet elevation. I drive my MH with OD on all the time. I have a big ATF cooler up front and I use Eneos Synthetic ATF. I don't however have a temp guage on the ATF. After passing each summit the tranny seems to NOT able to engage the OD for a period of time, does this mean the tranny is overheating? I tried to drive the MH at moderate speed. How does the fuel economy affected by using OD or not? Many thanks. Quote Link to comment Share on other sites More sharing options...
WME Posted February 2, 2010 Share Posted February 2, 2010 The trannie has an altitude cutoff switch for the O/D. Usually cuts off around 4000 ft and cuts on around 3500 ft Quote Link to comment Share on other sites More sharing options...
centralman Posted February 3, 2010 Share Posted February 3, 2010 The trannie has an altitude cutoff switch for the O/D. Usually cuts off around 4000 ft and cuts on around 3500 ft What is the purpose of the altitude cutoff? Quote Link to comment Share on other sites More sharing options...
Maineah Posted February 3, 2010 Share Posted February 3, 2010 What is the purpose of the altitude cutoff? More info then you would ever need http://www.patentstorm.us/patents/4474081/description.html bottom line engine output at altitude is reduced. Quote Link to comment Share on other sites More sharing options...
centralman Posted February 4, 2010 Share Posted February 4, 2010 More info then you would ever need http://www.patentsto...escription.html bottom line engine output at altitude is reduced. Thanks for your info. Since I have absolutely no idea on how to add an ATF temp gauge I would adhere to your advice by changing the ATF more frequently and try to drive a moderate speeds. Quote Link to comment Share on other sites More sharing options...
Derek up North Posted March 3, 2010 Share Posted March 3, 2010 Since I have absolutely no idea on how to add an ATF temp gauge ... http://www.bmracing.com/SPECIALS/Transmission-temperature-gauge-kit http://www.bmracing.com/bmracing/installation_instruction/9500048-08.pdf Quote Link to comment Share on other sites More sharing options...
86rader Posted March 27, 2010 Share Posted March 27, 2010 I use my OD most of the time on secondary roads where speeds are generally kept under 50 mph. On such roads lumbering along at 40 mph on flat ground, my drivetrain seems quite happy in OD. At the slightest hint of a hill though, I usually shut OD off before hand to try to build up a head of steam. On the interstate, it depends. If I have a tailwind or am going down hill or if I'm just not in much of a hurry and am content with 50 mph, I'll might leave it in OD. If I want a little more speed or am in a headwind, OD is off. A pretty good rule of thumb is if you find yourself giving it much throttle at all, you probably should be out of OD. As for the altitude switch, mine is connected and will probably remain that way seeing as I am a lowlander (east coast). If I were out west though, I would disconnect it for sure. When we did our big road trip a few years back, driving around the rapid city, sd area in OD was annoying as oooo as it is at the altitude where the switch activiates. Nothing more annoying that putting along happily in OD and the tranny keeps kicking down and up for no apparent reason. Quote Link to comment Share on other sites More sharing options...
86rader Posted March 27, 2010 Share Posted March 27, 2010 At 55 mph in 3rd, I am clocking about 3,000 RPM. Since the power curvedrops off dramatically below 2,500 RPM, shifting to OD will drop it ~1,000 RPM, well below the power curve. The motor may be turning slower,but it is lugging and my foot is closer to the floor. Even at 65 mph,the motor is purring ~ 3,400.I now use OD only when going downhill with the wind at my back. (Tho I still want to disable the altitude switch.) not sure i agree completely with this. The power curve probably does peak somewhere around 4000 rpm or so, this does not mean that running at 2000 is "lugging". The 22R is perfectly happy at these rpms. Does anyone know the torque peak of this engine? I think this is a better gauge of where the engine is at it's happiest and most efficient. I would guess it's probably around 2500 rpm. Quote Link to comment Share on other sites More sharing options...
86rader Posted March 27, 2010 Share Posted March 27, 2010 well, i went and looked it up. the 22RE torque peak is 3400 rpm, which is a bit higher than i would have expected. so, maybe it does make sense to let'er spin away. Quote Link to comment Share on other sites More sharing options...
Maineah Posted March 28, 2010 Share Posted March 28, 2010 well, i went and looked it up. the 22RE torque peak is 3400 rpm, which is a bit higher than i would have expected. so, maybe it does make sense to let'er spin away. Works out to around 3100 at 60 in O/D and 3500 rpm in 3rd you can't "lug" an automatic it will down shift. Peak torque does not mean peak efficiency. There are two things that will shorten the life of an automatic excessive stop and go and overheated fluid both can be avoided. The O/D debate will never end it's a personal choice but I'll wager both units at 125K will need an overhaul. Quote Link to comment Share on other sites More sharing options...
Gulfstream Greg Posted March 29, 2010 Share Posted March 29, 2010 Just got back from a trip to the Sierras. On the open highways and freeways where I could keep the speed up around 60 mph plus I used OD all the time. OK its a V6. OD kept locked in just about all the time and I had no problem keeping it at 60 to 65 mph in OD. It is just about 1000 rpm difference. Quote Link to comment Share on other sites More sharing options...
WME Posted March 29, 2010 Share Posted March 29, 2010 I got a lot different numbers. 65mph = 3500 in 3rd and 2400 in OD. OD ratio in an 43D is .688. These are just the math numbers, actual numbers will be a bit higher due to torque converter slip. WME Works out to around 3100 at 60 in O/D and 3500 rpm in 3rd you can't "lug" an automatic it will down shift. Peak torque does not mean peak efficiency. There are two things that will shorten the life of an automatic excessive stop and go and overheated fluid both can be avoided. The O/D debate will never end it's a personal choice but I'll wager both units at 125K will need an overhaul. Quote Link to comment Share on other sites More sharing options...
Maineah Posted March 29, 2010 Share Posted March 29, 2010 I got a lot different numbers. 65mph = 3500 in 3rd and 2400 in OD. OD ratio in an 43D is .688. These are just the math numbers, actual numbers will be a bit higher due to torque converter slip. WME OK it's a lot deeper reduction then I came up with and I respect Greg's observations all the more reason to leave it in O/D when you can! Quote Link to comment Share on other sites More sharing options...
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