What is "not normal" transmission behavior?

[SpaceNeedle]

I think my transmission is working just fine, but sometimes I think it does some things that may or may not be an idiosyncratic feature of the 4th gen 4Runner.

I figure if other cars do it, then it's normal and OK to continue running worry free. If it's just mine, then obviously I need to go consider having it investigated further.

The only weird thing going on right now is at a certain speed/rev range, if I press the throttle, the transmission/engine sometimes hesitates as if it's downshifting, but it's not downshifting I don't think. It's like a little hiccup. I can't reproduce it at will. It just happens sometimes and I take notice, but it's not a majorly disruptive hesitation. It's usually at the lower gears moving along and then giving a shove of throttle to acceleration a bit more briskly.

Otherwise, the car's been great. Shifts smoothly overall. No weird noises.

'04 V8 Limited 4x4

 

[chaz]

i think ive noticed what your referring to on my 06. it only happenes every so often, & at or coming up to a stop light. (slowing down ?) i just chalk it up to a computer error. i sure miss the old days when there wasnt so much computor involvment.

 

[eskimochaos]

I think my transmission is working just fine, but sometimes I think it does some things that may or may not be an idiosyncratic feature of the 4th gen 4Runner.

I figure if other cars do it, then it's normal and OK to continue running worry free. If it's just mine, then obviously I need to go consider having it investigated further.

The only weird thing going on right now is at a certain speed/rev range, if I press the throttle, the transmission/engine sometimes hesitates as if it's downshifting, but it's not downshifting I don't think. It's like a little hiccup. I can't reproduce it at will. It just happens sometimes and I take notice, but it's not a majorly disruptive hesitation. It's usually at the lower gears moving along and then giving a shove of throttle to acceleration a bit more briskly.

Otherwise, the car's been great. Shifts smoothly overall. No weird noises.

'04 V8 Limited 4x4

Its probably normal. Mine does some weird things as well.

Does yours shift buttery smooth EACH shift? I find mine shifting smooth one day then not so smooth the next day.

Im not talking about a manual car kinda shifting sensation but they are evident while some days you cannot tell at all even when "feeling" for the shifts.

 

[SpaceNeedle]

Re: Re: What is "not normal" transmission behavior?

Its probably normal. Mine does some weird things as well.

Does yours shift buttery smooth EACH shift? I find mine shifting smooth one day then not so smooth the next day.

Im not talking about a manual car kinda shifting sensation but they are evident while some days you cannot tell at all even when "feeling" for the shifts.

i think it's fairly consistent day to day or it doesn't vary enough that i really notice since i'm usually absent-minded in my commute...

i do notice that if i'm on an on ramp accelerating briskly, the shift from i think 3rd to 4th or 4th to 5th at 65mph or so does shift slower than the ones from 1-2, 2-3. this has been consistent.

otherwise, tranny's OK. it's just that sometimes if i'm slowing downa nd then need to accelerate, it doesn't the one time hesitation... sometimes. i can't reproduce it at will as noted.

brraaaaah - hiccup - braaaaahhh.... brake... try again... brrrraaaa-hiccup - brraahhhh... brake... try again later.... brraaaaaaaaaaaa (doesn't do it)

 

[chaz]

thats similar to mine, every now & then, when i slow down for a red light, then give it a little gas, it almost feels like a slip, or its trying to find the right gear. it does seem like thats normal for these.

 

[4RunnerStunner]

I noticed after I sprayed my MAF Sensor this weekend, the shifting was smooth as glass. I would put it into reverse and you could feel it, but now I can hardly feel it shift. It could be because I changed the differential fluid and oils this weekend too but it did not smoothen out idle wise until I sprayed the MAF. The ride is 100 time better.

 

[SpaceNeedle]

I noticed after I sprayed my MAF Sensor this weekend, the shifting was smooth as glass. I would put it into reverse and you could feel it, but now I can hardly feel it shift. It could be because I changed the differential fluid and oils this weekend too but it did not smoothen out idle wise until I sprayed the MAF. The ride is 100 time better.

smooth as glass here too just the hiccup sometimes.

i can't feel a shift into reverse either.

 

[Mercedes]

Mines does the samething, I just presumed it was normal, along with the anoying steering wheel vibration:bash:

 

[riverwolf]

Spaceneedle, if I understand your description, I can think of several things you might be observing, and I'd call them all normal.

The first thing that came to mind is your getting back on the accelerator hard enough to unlock the torque converter, but not hard enough to ask for a downshift. The A750s will lockup in 3/4/5 and try to do so as quickly as possible...programmed to get every last bit of MPG available. It's not quite like disengaging a clutch, but there's a moment of not pulling. Just a slight variation in how much pressure you apply will determine whether you can accelerate without unlocking or not. You can see the unlock on your tach as a 200-300 rpm jump...a gear change would be much larger.

If there was a downhilll slope involved sometimes and not others, you may be experiening Toyota's "grade logic" feature. The 4Runner's have an inclinometer in the dash cluster. On downhill slopes, based on the inclinometer reading when you touch the brakes, the computer's "grade logic" will downshift to use engine braking to assist the brakes. Get back on the gas and you're already in the right gear to accelerate; no fuss, no muss. Now, slow down on flat terrain and the MPG logic is in charge...maintain the highest gear/lowest RPM as long as possible...suddenly you ask for throttle, but your speed/load is now more appropriate for 2nd, but you're still in 4th or 5th...hesitate-while-computer-finds-right-gear/shift/bang/GO.

Lastly, one or two others sound like they might be describing the driveshaft binding in a 4wd model. There's a huge thread on this somewhere. In a nutshell, the driveshaft(s) can get a bit twisted up as you come to a stop. When you let off the brake, the tension is released. At its worst, you're looking in the mirror for the idiot who just rear ended you, but no one's there. The simple cure for this is regular lubrication of the slip joints; documented in the owner's manual.

HTH, Brent.

 

[chaz]

riverwolf, that sounds like the best answer, & makes alot of sense. thanks

 

[4RunnerStunner]

Spaceneedle, if I understand your description, I can think of several things you might be observing, and I'd call them all normal.

The first thing that came to mind is your getting back on the accelerator hard enough to unlock the torque converter, but not hard enough to ask for a downshift. The A750s will lockup in 3/4/5 and try to do so as quickly as possible...programmed to get every last bit of MPG available. It's not quite like disengaging a clutch, but there's a moment of not pulling. Just a slight variation in how much pressure you apply will determine whether you can accelerate without unlocking or not. You can see the unlock on your tach as a 200-300 rpm jump...a gear change would be much larger.

If there was a downhilll slope involved sometimes and not others, you may be experiening Toyota's "grade logic" feature. The 4Runner's have an inclinometer in the dash cluster. On downhill slopes, based on the inclinometer reading when you touch the brakes, the computer's "grade logic" will downshift to use engine braking to assist the brakes. Get back on the gas and you're already in the right gear to accelerate; no fuss, no muss. Now, slow down on flat terrain and the MPG logic is in charge...maintain the highest gear/lowest RPM as long as possible...suddenly you ask for throttle, but your speed/load is now more appropriate for 2nd, but you're still in 4th or 5th...hesitate-while-computer-finds-right-gear/shift/bang/GO.

Lastly, one or two others sound like they might be describing the driveshaft binding in a 4wd model. There's a huge thread on this somewhere. In a nutshell, the driveshaft(s) can get a bit twisted up as you come to a stop. When you let off the brake, the tension is released. At its worst, you're looking in the mirror for the idiot who just rear ended you, but no one's there. The simple cure for this is regular lubrication of the slip joints; documented in the owner's manual.

HTH, Brent.

It is funny you should mention the tension release. I just talked to a mechanic at the dealership yesterday about that. It happens on 2wd's also. Mine is a 2wd and I have had it do this to me a few times. The mechanic said this is a known thing with 4Runners as you know probably already know and this behavior is normal. I have not had this problem at at after I changed the gear oil. It may come back of course.

 

[SpaceNeedle]

Spaceneedle, if I understand your description, I can think of several things you might be observing, and I'd call them all normal.

The first thing that came to mind is your getting back on the accelerator hard enough to unlock the torque converter, but not hard enough to ask for a downshift. The A750s will lockup in 3/4/5 and try to do so as quickly as possible...programmed to get every last bit of MPG available. It's not quite like disengaging a clutch, but there's a moment of not pulling. Just a slight variation in how much pressure you apply will determine whether you can accelerate without unlocking or not. You can see the unlock on your tach as a 200-300 rpm jump...a gear change would be much larger.

If there was a downhilll slope involved sometimes and not others, you may be experiening Toyota's "grade logic" feature. The 4Runner's have an inclinometer in the dash cluster. On downhill slopes, based on the inclinometer reading when you touch the brakes, the computer's "grade logic" will downshift to use engine braking to assist the brakes. Get back on the gas and you're already in the right gear to accelerate; no fuss, no muss. Now, slow down on flat terrain and the MPG logic is in charge...maintain the highest gear/lowest RPM as long as possible...suddenly you ask for throttle, but your speed/load is now more appropriate for 2nd, but you're still in 4th or 5th...hesitate-while-computer-finds-right-gear/shift/bang/GO.

Lastly, one or two others sound like they might be describing the driveshaft binding in a 4wd model. There's a huge thread on this somewhere. In a nutshell, the driveshaft(s) can get a bit twisted up as you come to a stop. When you let off the brake, the tension is released. At its worst, you're looking in the mirror for the idiot who just rear ended you, but no one's there. The simple cure for this is regular lubrication of the slip joints; documented in the owner's manual.

HTH, Brent.

Brent,

I definitely understand the "inclinometer" deal as there's a decent decline on the way home and the computer keeps the truck in a lower gear to use engine braking like I would in a manual car. I'm also familiar with binding in a turn and also the clunky stop-go which is pretty much always around.

I think you hit the nail on the head with the torque converter lock-up which I haven't heard about prior. It's exactly the type of throttle input (half?) where I can tell the engine isn't downshifting, but it is somehow hesitating for me to hear and feel it doing so and then the car scoots forward in whatever gear the computer decided to select.

I'm totally down with the maximize mgp Toyota algorithm.

Thanks for the explanation. Well done.