Overdrive in low range.

[Lightspeed]

Hi just a quick question i did a search on & couldn't find an answer.
Can you use overdrive in low range as a 4th gear toyota 1hd-ft with a442f auto. Thanks for any replies.

 

[Cutrex]

Yes, you can. Just leave the O/D button pressed, and the shift will come in due time.

 

[crx7]

Disagree, mine has never shifted to OD while in low range.

 

[Lightspeed]

Yes, you can. Just leave the O/D button pressed, and the shift will come in due time.

Good stuff thanks

 

[Lightspeed]

Disagree, mine has never shifted to OD while in low range.

I have discounted the transfer case switch which allows me to use low range without the transmission lock on, i use it for towing on sealed roads sometimes. Maybe with that my OD might work. Just didn't know weather it was ok to do so. Thanks for the reply.

 

[crx7]

I think you mean you have the modification and switch which allows Awd in low range allowing the center diff lock to be off in low range. I have that as well and it still doesn't shift into overdrive in low range.

 

[Cutrex]

Disagree, mine has never shifted to OD while in low range.

In low range, it will shift at approximately 3500 rpm. I think it probably relates to the overall gear ratio. Mine is a 1HD-T with A442F, 1:4.10 and 265 75/16. With that ratio, the only scenario where I was able to reach 4th gear in low range was driving along a beach. Previously, I thought that she would not shift even to 2nd gear, as I never revved enough the engine. Once a gear beyond 1st is reached, it will downshift as soon as revs are lowered, therefore arriving at 4th gear requires some determination and cold blood.

By the way, I found it after my mechanic told me that, in a situation like said beach or sand dunes, it was preferable to roll in 4th gear low at 3500 rpm, which locks the torque converter, than simply circulating in 4th gear high, even if the car appears to be powerful enough. The latter causes frequent shifts between 3rd and 4th, which overheats the torque converter and ultimately compromises engine cooling.

 

[Lightspeed]

I think you mean you have the modification and switch which allows Awd in low range allowing the center diff lock to be off in low range. I have that as well and it still doesn't shift into overdrive in low range.

Is that the one where you bridge a wire on the transmission ecu. I just disconnected the transfer case plug & it does the same thing.
I can press the switch on the dash & have it locked in hi & low 4wd or unlock 4wd using the switch & still use low 4wd with no centre lock.

 

[Lightspeed]

Well I went out bush today & my 80 does shift into OD both with & without the transmission lock on.
It shifts smoothly & at reasonably low revs.

 

[crx7]

What kind of speed are you guys seeing in overdrive in low range?

 

[LandLocked93]

What kind of speed are you guys seeing in overdrive in low range?

The slow kind. lol
Maybe 35mph@2200rpms

 

[Lightspeed]

The slow kind. lol
Maybe 35mph@2200rpms

Yes but its better than 3rd lol

 

[crx7]

Strange, my 1FZ-FE will only shift to 3rd in low, I max out at about 25mph

 

[LandLocked93]

Not sure that it does, but maybe the ECT button plays a part somehow? And I don't think all models have that button.
At any rate, not sure you're missing anything. IME, it seems to be just the last gear of a linear shift program and I've never found a legit use case for it. Doesn't mean there isn't one of course, but if I'm on a trail requiring LO to begin with it's rare (or accidental) that more speed ever becomes necessary on that same trail.

 

[ChaseTruck]

Our '93 shifts into OD while in low range quite readily, don't have numbers but it's much earlier that 35mph.
There's a connector (I think it's on the t'case) you can unplug and you'll get the high-range transmission shift pattern in low range.
@Tools R Us did this for us a long while ago, and I haven't found the need to go under there and find out details. I like that shift pattern better on the trails than the original low range shift pattern.

 

[Lightspeed]

Not sure that it does, but maybe the ECT button plays a part somehow? And I don't think all models have that button.
At any rate, not sure you're missing anything. IME, it seems to be just the last gear of a linear shift program and I've never found a legit use case for it. Doesn't mean there isn't one of course, but if I'm on a trail requiring LO to begin with it's rare (or accidental) that more speed ever becomes necessary on that same trail.

I wanted it for towing the off road caravan I have & the extra legs come in handy between the slower stuff. All good works well.