1996 Dodge B3500
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'96 Dodge B3500 ... Any Idea What This Button Does?
- Thread starter CCI
- Start date
Overdrive off?
I think it turns on/off the overdrive.
Overdrive. We had a 1992 D150 that had the OD button on the upper dash.
Long before tow/haul buttons, Overdrive Off was the tow/haul button.
When you only had 4 forward gears, it was easy to lug the engine.
When you only had 4 forward gears, it was easy to lug the engine.
yes overdrive off, but what does it practically do? It doesn't prevent the use of the 4th gear, and there isn't an extra overdive unit (like some cars had). So to me it seems it actually changes the shift parameters to downshift sooner, upshift later?
It does prevent the use of 4th gear.
You get 1, 2, 3 and torque converter lockup.
Doesn't change the shift points at all on anything I've driven. Maybe on a GM. But I know Ford and Chrysler products don't change shift points when OD is locked out.
The older 4 speed automatics were kinda dumb and would prefer to be in 4th gear with the torque converter unlocked (using more fuel, making more heat) than to downshift to 3rd/direct/drive and have the torque converter locked up. Sometimes you had to do it yourself.
When towing, the lighter ones weren't able to tow in overdrive without damaging things. Sun shell failure, clutch failure, etc. Heavier duty ones could but the programming wasn't great and you'd end up in the situation above. I think that's why so many 4r100/E4ODs blew out their pump seal. They can't tolerate heat at all and the factory logic leads them to overheat very easily.
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I don't remember, but I had it on a c1500 back in the day (it was part of the shift pattern). it was kept in overdrive most of the time anyway.
Heh, my wife ignores me when I tell her to lock out OD in town or on hills (up or down). "It's an automatic, it should do it automatically." Mind you, she loved driving manual transmissions--to her, if it's going to be an automatic, and cost more, then it should just do its job correctly.
I think part of the reason for this button is because OEM's were cheap and were retrofitting 3 speed column shifters (and console) to now handle 4 speeds. It was easier to add a switch, apparently, than to redesign mechanical bits to get 4 detents. Never underestimate the desire to avoid doing work... or spend a cent. Plus by the time the overdrives were popping up, it was becoming the norm to have some level of electronics, so it kinda integrated--not all OEM's are the same, but this is my guess as to why a button and why for so long after 4AT was the norm (like most of the 90's for most of the cars, a few 3AT holdouts notwithstanding).
I think part of the reason for this button is because OEM's were cheap and were retrofitting 3 speed column shifters (and console) to now handle 4 speeds. It was easier to add a switch, apparently, than to redesign mechanical bits to get 4 detents. Never underestimate the desire to avoid doing work... or spend a cent. Plus by the time the overdrives were popping up, it was becoming the norm to have some level of electronics, so it kinda integrated--not all OEM's are the same, but this is my guess as to why a button and why for so long after 4AT was the norm (like most of the 90's for most of the cars, a few 3AT holdouts notwithstanding).
Thank you all!
This vehicle doesn't have a tach so it's all a guess until I get used to this new-to-me feature.
Is it best to engage this switch (turn OD off) if it feels a little sluggish under load, or going uphill, or when a little more engine braking is needed going downhill?
Is it best to engage this switch (turn OD off) if it feels a little sluggish under load, or going uphill, or when a little more engine braking is needed going downhill?
All of the above?
In general, it's best for the transmission to not shift when under a load. Modern setups have communication between engine and trans, and power will be cut for the time it takes for the transmission to shift. A vehicle this old? I don't think it has that.
To be clear, you should be able to drive this w/o touching the button, and it should be fine. Don't worry about damaging it.
That said, as you go about, if you know that it's going to kick out of overdrive on a particular hill... kick it out (turn off OD) at the bottom, before you have to get onto the throttle. Leave it off when descending as that saves on brakes (engine braking).
You may find that in rolling terrain, driving along at 40 or 45mph or so, that it just keeps going into and out of overdrive. Or locking and unlocking the convertor. Perfect time to lock out OD. I say 40 or 45mph, maybe it's 35/40. When it seems to just not hold overdrive and/or locked, feel free to just lock it out.
Torque convertor lockup is a bit harder to explain... it's like a gear shift, but less of an rpm change, and you can "tell" when it's locked vs not by how engine rpm changes. Locked up, rpm will not change with a bit of gas, not without it picking up speed. Unlocked, a bit extra gas will make rpm go up a bit but not actually change speed (or it seems that speed lags). Unlocked torque convertors make heat. This is what you want to avoid, when going up hills--but around town, it's not a bad thing, or I should say, nothing like the heat that will be generated while climbing hills.
Are you sure it doesn’t prevent 4th gear?
IIRC the 46re is basically just an electronic OD grafted in to an old 727 three speed, and with the lockup converter of the a500/a518.
No I'm not, it's been over 20 years since I drove anything like that. And I used it at low speeds only, with overdrive engaged 99% of the time. But if it locks out 4th, it should show 3. like you have 2 or 1 on the selector to select the highest possible gear.
The "shift" you feel into fourth is likely just the converter clutch locking. Since the Chrysler trans design ethos was to have really sloppy converters with high multiplication ratios, the difference in locked vs unlocked RPM isn't subtle, and it can certainly appear to be a gear shift.
Of course, if the old 727 didn't have such a tall 2.45 first gear, they wouldn't have needed such a loose converter.
I drove chevy.
Got it and thank you.
