couple of hopefully non-stupid 4WD questions

ok.. 2015 V6 manual...

the book for the truck says dont go above so and so speed, in each gear, when using 4WD. is that bullshit or what? ive seen even big name magazines test the 0-60 of this and other trucks with the 4wd active in order to squeeze every last bit out of the vehicle and establish a 0-60mph time.

other question is, is there any option for regearing the late model 2nd gens for better mileage in 6th? this thing turning 3k rpm on the highway is nonsense. what the hell were they thinking? im sure its to do with towing but hell, no one tows ALL the time =P

completely stock truck so far, except for factory quick shift.

i made the usual cursory search of this and that term, looked through the first couple pages of results but no joy. really thought id find something..

 

Sixth gear is lot shorter than overdrive with the auto trans. Pretty well known fact among Tacomas. Good news is, it works great with taller tires.

You could possibly re gear the differentials for about $3k, and lose performance, but you would never make up that money in gas for an extra 1mpg or so.

 

80 miles per hour is speeding in the vast majority of states

Mine cruises nicely at 65.

 

You honestly shouldn't need 4WD at all on the highway... if I recall, it's recommended to use 4hi at 60 mph or lower and 4lo at 5 mph or lower.

 

I'm not sure I understand, but I'll take a stab. I think you are confusing (AWD) All Wheel Drive with (4X4) 4 wheel drive. AWD vehicles can safely be driven on any road surface. 4X4 should NEVER be engaged unless you are in a situation where you have poor traction. If you NEED 4X4 I can't think of any situation where it'd be safe to drive over 25-30 mph. Even though it may not damage components to drive faster.

Each of the 4 wheels on any vehicle must be able to turn at different speeds when cornering. The outside wheels must turn MUCH faster just to keep up. An AWD vehicle will sense that and send power to each wheel differently. Great for wet roads or light snow. Not so good in much more rugged off road situations.

Your Tacoma is true 4X4. When engaged it sends the same power to both the front and rear wheels giving much better traction in harsh conditions. But when you turn the wheels sharply the inside wheels will slip slightly on the slippery surfaces in order for them to turn at the same speed as the outside wheels. Put it in 4X4 in pavement even wet pavement or hard surface dirt and it puts the entire drive train in a bind. You risk breaking axles, drive shafts, or the transfer case. It may not break from limited use, but you are doing damage and will shorten the life of components.

I once had a 1975 Jeep truck that used vacuum lines to control the 4X4 system. It was AWD most of the time, but switching to true 4X4 was possible. At some point before I bought it the vacuum lines got reversed. I was driving in 4X4 all the time. I had the transer case rebuilt twice within 6 months before the problem was found. I knew not to use 4X4 on the road, but a teenager and not experienced enough to realize the problem. I'd figure it out pretty quick now from experience.

 

if you are off road.... run the bitch in 4hi as fast as you want... keeps the ass end from dancing around at higher speeds.

Hit rev limit in 5th (auto) a time or two in 4 low as well messing around.... it doesnt hurt anything, just make sure you are on a low traction surface.


Nothing you can do about the shitty OD ratio on the 2nd gen 6 speeds.... 255/85R16's sound like they are in your future.

 

255/85 is awesome for DD with the 6 speed, they make reverse even worse though. I think I'll gear for more torque. I'll be okay holding up traffic going 60 - 65 at 2500 rpm

 

I agree with all of what you said. Except this: "If you NEED 4X4 I can't think of any situation where it'd be safe to drive over 25-30 mph." I'm not really disagreeing, but just want to add... In the upper Midwest we often drive on the interstate/highways on ice/snow at near normal highway speeds. I know it sounds nuts to people in other parts of the country that don't see those conditions often, but it's the norm up here. For the sake of safety, I often use 4-high on and off in those conditions and at those speeds. With the new traction control systems, I find that I don't use it as often, but there are still times when I do.

Whether it's safe to be driving over 25-30mph in those conditions... That's a whole 'nother thread. If we didn't, we'd be shut down from December to April.

 

I'm assuming you run 4Hi?

I ask because I'm new to 4wd and just want to be sure of what you're saying.

 

Yes, he means 4hi. 4lo at the drag strip would not win him many races - well, maybe from zero to 50 feet.

 

Thanks!

 

"other question is, is there any option for regearing the late model 2nd gens for better mileage in 6th? this thing turning 3k rpm on the highway is nonsense. what the hell were they thinking? im sure its to do with towing but hell, no one tows ALL the time ="
My 6sp with OEM size tires turns 2450 at 67mph.

Towing with the 6sp, to me it makes more sense to use 5th (1:1) if you can't hold speed in 6th. Personally, I think Toyota wanted the automatic to give better mpg than the manual, maybe for the EPA rating (have heard only 6% of Tacoma V6's are manual trans). What is particularly bad is the FJ had the v6,6speed with a .79 (IIRC) instead of the Tacoma's .85 - but it had a 3.90 axle instead of 3.73.

 

headed your way!!! prepare!

 

3k in 6th is going to be over 80, probably more like 85.

 

FWIW there are parts of the country where the posted speed is 80mph. Driving 60mph is a traffic hazard and not safe.

 

There are parts of the country where people drive 80 on snow and ice and if you're not doing at least 60 you better get off the road.

When I was younger I was out there with 'em. I avoid it at all costs now. Those are the times I'd run it in 4wd at those highway speeds. Never ran into any mechanical problems. Not ideal, I realize.

 

If you're driving 80mph in a Tacoma fuel economy is the least of your concerns, even with lower revs the aerodynamics will not give even remotely decent fuel economy.

 

Agreed. My VW tdi gets 45mpg at 80mph. Having a Tacoma for mileage period is questionable, especially at 80.

 

thats entirely true, but besides the point, quite frankly. my commuter vehicle is a sportbike. 40mpg if i keep it under 90 =]

i was just curious IF there were some transmission/diff related options that would cause the truck to run lower rpm while at highway speeds in 6th gear. i wouldnt assume it to be a big difference, something like 2mpg improvement.

it sounds like the answer to my second question is no, there is no limit to how fast you go in 4hi, or exactly what speed/rpm you go in whichever gear while in 4hi.. yes? i know the thing about components starting to bind if the wheels are turned too much (more than 40 degrees, seems like) since i experienced that in my own driveway haha, going only about 8mph so not like anything broke the truck just kinda stopped as if under very heavy engine braking. i had to reverse a little and straighten the wheels, take it outta 4wd then went on my way.

i think the rear tends to get too squirrelly in some cases, clearly the factory shocks arent very good. disappointing since all things considered, the TRD tacoma isnt cheap. =P got a hot date with an all-around OME package toward the end of this year, probly. xmas present to myself maybe? woot..

thanks for the responses, i had a 2015 2wd 4cyl taco oct last year and couple months ago traded it in on this, first time i ever had a truck.. ill be back with more dumb questions at some point im sure =]