mini-wini-dan Posted July 18, 2013 Share Posted July 18, 2013 I am en route to California in Mount Rushmore area and today it appears that I have lost my overdrive option. I notice hearing some noises in the steering column area just before I lost it. This must be an electrical problem with the switch? Any suggestions? Other wise the vehicle is running great but I have lost over-drive which will hurt gas mileage. I would like to get this fixed and could have it looked at while in San Francisco while visiting family but that is about 1500 miles away. Quote Link to comment Share on other sites More sharing options...
linda s Posted July 18, 2013 Share Posted July 18, 2013 The overdrive shuts off at anything over 4000 ft. There is no reason to use overdirve on the 4 banger. Will run just fine without it and will save your trannie. Only to be used on very flat roads with no headwind or down hill. No locking torque converter and the heat created by the slippage will toast your trannie big time. I have been driving mine for 10 years without ever turning it on and my trannie is still fine. Just checked elevation for the area and you are indeed above 4000 ft. Nothing wrong with the overdrive. Linda S Quote Link to comment Share on other sites More sharing options...
mini-wini-dan Posted July 19, 2013 Author Share Posted July 19, 2013 Thanks for the info Quote Link to comment Share on other sites More sharing options...
jmowrey Posted July 19, 2013 Share Posted July 19, 2013 I'm a new owner of an 85 Dolphin 22RE automatic with overdrive. I'm in Santa Fe at 7000+ feet. My overdrive works just fine, when I use it. But like Linda said, it's not much use except on very flat, easy cruising terrain. Otherwise, the tranny spends all its time hunting for a sweet spot and shifting up and down for no good reason. Perhaps I have a different version of the overdrive which would explain why it works at this altitude.??? Quote Link to comment Share on other sites More sharing options...
linda s Posted July 19, 2013 Share Posted July 19, 2013 I'm a new owner of an 85 Dolphin 22RE automatic with overdrive. I'm in Santa Fe at 7000+ feet. My overdrive works just fine, when I use it. But like Linda said, it's not much use except on very flat, easy cruising terrain. Otherwise, the tranny spends all its time hunting for a sweet spot and shifting up and down for no good reason. Perhaps I have a different version of the overdrive which would explain why it works at this altitude.??? If your Dolphin has been in the Santa Fe area long or anywhere along that high plateau it's possible that a previous owner disconnected the overdrive kill switch. Only way it could possibly still be working. But again even with an extra trannie cooler it can cause excessive wear on the transmission. 22re runs just fine in 3rd forever. I tried overdrive many times on a very flat road and I got worse mileage everytime. All that slipping back and forth trashes any savings you might expect to get from overdrive. Linda S Quote Link to comment Share on other sites More sharing options...
Bob C Posted July 19, 2013 Share Posted July 19, 2013 Last summer I went from Wisconsin to Wyoming/Montana. I am glad that I had heard (on this great site) that my OD would not work at higher elevations. I lost my OD somewhere in South Dakota. According to my GPS altimeter, I was at about 3800 ft when it quit working. I would have been freaking out and thinking that my transmission was about to take a crap if I had not heard about it in advance. Quote Link to comment Share on other sites More sharing options...
zero Posted July 19, 2013 Share Posted July 19, 2013 It would be intertesting to see some hard specs on the difference between using OD and not. I'm talking about flat highway driving. I never drove a heavy Toyota any distance before with the A43D until this week so I have little personal experience. I drove 75 miles mostly in OD on flat highways and it felt fine. That is . . no lugging at 55 MPH. If I'd wanted to go faster - I'd be pushing down on the pedal and working it. There was a huge difference in engine RPM between 3rd gear (1-1 ratio) and when in OD (.68 - 1 ratio). The former owner claimed he used OD most of the time and got better MPGs. True or not - time will tell. He owned the 20' RV for 40,000 miles and it presently has 140,000 miles. I have no way of knowing if it's ever been rebuilt or original. The only way to verify excess torque-converter slippage is if someone has a tachometer installed. A Toyota RV with correct tires, 4.10 rear and A43D trans with optimal slippage ought to have the engine spinning at 3000-3400 RPM at 55 MPH in 3rd gear. 2100-2400 RPM @ 55 MPH in OD. If OD was causing excessive slippage there would be more disparity between the figures. Zero slippage as with a manual trans or lock-up converter would be 2975 RPM in 3rd and 2050 RPM in OD. Normal and acceptible torque converter slippage is 10-15%. As to heat problems? The only way to verify is with a temp gauge and to measure any differences. Also - many auto transmissions for HD applications with OD have heat sensors to prevent OD when over a certain temp. I have no idea if the A43D has anything like that. There were many variations of the A43D used in Toyota trucks. An auto engine is most efficient when run at the peak of its torque curve. With the Toyota 2.4, that is at 2800 RPM which is pretty high. There are other factors that affect gas mileage though. Obviously, fuel mileage is pretty easy to check and verfify. No special equipment needed. With the RV I just got - even if fuel mileage stay the same in 3RD or OD, I'd choose OD when on flat roads simply due to the lesser noise and RPMs. That is, unless I vefiried it causes a problem. I might stick a tach on mine today and see if OD causes any extra slippage. Quote Link to comment Share on other sites More sharing options...
jmowrey Posted July 19, 2013 Share Posted July 19, 2013 If your Dolphin has been in the Santa Fe area long or anywhere along that high plateau it's possible that a previous owner disconnected the overdrive kill switch. Only way it could possibly still be working. But again even with an extra trannie cooler it can cause excessive wear on the transmission. 22re runs just fine in 3rd forever. I tried overdrive many times on a very flat road and I got worse mileage everytime. All that slipping back and forth trashes any savings you might expect to get from overdrive. Linda S Hi LInda, Very strange. I bought the Dolphin in Michigan in May. So it's been at 7000 feet for two months, though not driven more than a couple of hundred miles since I brought it home. The overdrive switch is definitely still working (assuming you mean the little button on the shifter--I don't know nuttin' about nuttin' about this stuff! I'm a real novice). I can hit the switch and it does shut out the overdrive as expected. I don't use it a lot because of the hunting problem, shifting back and forth constantly, very annoying. Besides, it does seem to cruise just fine in third. So I mostly shut out the overdrive and use it as a three speed, kinda like the standard shifters on the steering column my Chevy had back in the old days. (here I go, dating myself!) Thanks for all the good advice. It's an interesting learning curve. Quote Link to comment Share on other sites More sharing options...
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