Been Driving in 4 instead of D how bad is that.

Why would anyone drive at 55 or 65 mph in 4 unless you were towing ?

 

no harm, no foul. with the 3.73 gears in my truck, 2.5k is normal highway driving...

 

Long grade with cruise control on. Keeps it from hunting. Steeper grade you may pull the same trick with 3. But yeah, a pretty special case in general besides the more obvious towing case.

 

The ones that drive in 4 and don't realize that they are like the OP.

 

I live in Kentucky and find that my truck dose a very good job handling hills in D while in cruise it rarely if ever hunts except for the most steep grade in which case I will kill cruise anyway. Only time I drop from D is on steep downgrades on narrow roads to use the engine brake speaking non towing situations. Of course in an off road situation I often start in 3 and go down as needed.

 

You will be fine, I usually keep mine in 4 when I'm in a lot of traffic that seeds up and slows down a lot. I also use 4 when I tow but I must say the truck to me always feels like it needs to shift when in 4, just doesn't seem happy. Could just be that I am used to the overdrive and I am waiting for the shift lol.

 

I use 4th a lot when going downhill; engine braking. Sometimes I forget to shift back to d, but if I ever get over say, 45 the faster engine revs are VERY noticeable.

 

LOL ^ This

OP: I mentioned in another post how the placement of the shift knob brings back memories of driving a stick shift - which I haven't done for YEARS. When I got my Tacoma I accidentally shifted from D into 4 purely by muscle memory. All it does is limit which gears the transmission will utilize while you're driving.

No harm, no foul.

 

Wut?

 

It says not to use D (overdrive) while towing in the manual I do believe.

 

Tow in D is fine unless it's hunting back and forth a lot , in that case leave it in 4

 

At the risk of sounding ignorant. Can you elaborate more on engine braking?

 

Because there is friction inside the engine allowing the motor to run at higher RPMs (in a lower gear than needed) you can use the engine to slow you down (less use of your brake pedal). Simply letting up on the gas pedal allows the engine's RPMs to come back down. This causes the vehicle to slow (especially when in low gears). So you are using the engine's friction, which is attached to your transmission, which is attached to your drive axle, to force the wheels to slow down. This can be more effective than simply applying the brakes. Especially going down hills.

This is how semi trucks go down steep hills without having their brakes go out! And many folks with manual transmissions learn to do this as they approach stop lights. Next time you're driving let off the gas while your RPMs are high (before it shifts to a higher gear). You'll feel the vehicle slow a bit.

 

Don't sweat it. I started this same topic several months ago. I drove mine about 6K miles! Almost 20K now and no problems. I don't drive to fast, so I didn't tax the motor much.

 

At the risk of being pedantic, but just to be clear to the person who asked the question...

In this case "friction" might not be the best word to use. The description is completely accurate in the sense that the engine with throttle closed still connected to the wheels will provide resistance akin to braking and the higher the RPM the more resistance it will provide. However, the source of that resistance isn't really "friction" in the sense of engine or drive train parts rubbing. What is happening in a gasoline engine is the wheels are still mechanically connected to the pistons of the engine through the drive train. With the throttle closed (of course it is never totally closed) when the pistons go down they can't draw air into the piston effectively. This creates a partial vacuum in the cylinder. Effectively the vacuum in the cylinder tugs on the head of the piston which is still connected to the wheels. So the resistance is really coming from resistance to air flow through the restricted (almost fully closed) throttle.

Diesel engines in trucks are actually quite a bit different as they don't really have a throttle valve at all. So instead they usually do things on the exhaust itself or the exhaust stroke of the engine to create the resistance that the closed throttle does in a gasoline engine. Basically with a Diesel you've got to add something on to get a braking feature from the engine. And with Diesels these techniques can be very, very noisy. Which is why when a big truck uses an "engine brake" of some form next to you on a hill you know immediately!

But yeah, otherwise the above description nails it - leave the wheels connected to the engine and close the throttle and the engine acts like a kind of brake. It is a very good way to maintain reasonable speed on long downhill grades. In fact it is the safest way to do this. Modern brakes are very safe with dual master cylinders. However, if you ride the brakes down a long grade you can still heat the brake fluid to the point at which your brakes don't work anymore. And of course both halves of the brake system get just as hot so the redundancy of a dual master cylinder doesn't buy you a thing and no more brakes for you. Which is a "bad thing". So use lower gears for engine braking on long downhill grades - it is the safer thing to do.

 

I've noticed this before. I drove 5 speeds all through high school so I can relate to what you mean by using your gears to slow you down... Neat. Learn something new every day!

 

I have a lot of experience driving diesel trucks, small and large(ish). Engine brakes come in many flavors - including exhaust and transmission. Most of the trucks I have driven have had exhaust brakes, but they can be turned off. Every one of them slows when you take your foot off the accelerator even with the brake turned off, just like a gasoline vehicle. The exhaust brake is there to assist the engine even more, especially under heavy loads.

Just thought I'd add that. Carry on...

 

Ahhh yes, of course. I read it as towing in H4. My old Dakota had a tow button that kept the trans from going into OD. If you didn't it was very easy to burn up those transmissions when towing. Do the auto Taco have something similar?

 

Yes - that is what the "4" position is.

On the AT the numbers are the highest gear the AT can use, but it can still use lower gears as necessary. So if you want to lock out OD just select the 4 position and the AT will use all gears except the 5th (aka OD).

That's for the 5 sp AT on the V6. With a 4 sp AT obviously the 4th gear is the overdrive and 3 would be your "no OD" position to use.

 

Yea, am more than familiar.