Has anyone done a 4.56 on their third gen or just 4.88?

I needed an alignment so I havent gone on the highway yet but I will today or tomorrow and report back on my rpm's at 75mph.

 

Im running 265/70/17 and at 75mph I was at 2300 rpm. It felt better at highway speeds. I often felt like the rpm was too low to handle a headwind or incline at 65-75pmh. I would have to give it so much gas to overcome, now it stays in the pocket a little better and its not so bogged down. It also stays better in town. Thats where I see the biggest boost of enjoyment. at 35-45 the rpm are much better and dont sit at 1000 where you have no power at all.

all of that being said. its still an under powered engine and it still has poor software for the transmission. I like the truck much better but I would have loved a supercharger option.

 

Sounds like a good solution that a lot of people are looking for, I plan on doing the 4.88's on my auto since I tow a big boat.

 

What's the factory gearing and what's the advantage of changing it?

 

Factory v6 automatic gears are 3.91. The 4.88s give a little more mechanical advantage, putting more torque to the wheels at the expense of higher RPM. This compensates for larger tires or towing heavier loads.

 

So if I'm not towing and aren't running 285's is there any advantage to re-gearing?

 

Not really,, You'd probably be at too high of an RPM on the highway.

 

The advantage is more torque off the line and faster initial acceleration, seems the shift points from the ECU are too early anyways so an extra 600 rpms before shifts is only going to keep the motor in the power band better especially running the truck without ECM button pushed. When I get it done Ill report the results using my stock 265/70/16 tires. Disadvantage might be worse mpg on longer highway drives, although I think I might see better mpg while towing. Changing tires to 33's gets the gearing closer to stock but not quite, I can always put bigger tires on ..LOL

 

You ever end up doing this in stock tires? Curious because that is what I would want to do.

 

Toyota does make 4.56 gears (and 4.30) for the 3Gen 8.75 diff.
This thread has the part numbers and final achieved drive ratios.
https://www.tacomaworld.com/threads/can-you-buy-the-4-30-gears-from-toyota.470088/page-5

 

FYI an auto with 4.88 is still geared higher than a stock MT. You’ll be fine. You’ll take a minor mileage hit but it will more than worth it.

 

sub'd

 

Nice, hadn't seen that before. The Toyota gears are still more expensive than 4.88's though

4.30's would be perfect with the auto and 33's - 4.88's just seem like a little TOO much gearing...especially for me since I drive 80mi. per day on the highway.

 

I have the 4.30 in my manual transmission, and I'm thinking about going to 4.56 if I can find 'em. Right now I run 275/70/17 summer tires, and 265/70/17 winter tires. I think I'd have to bump up to 285/70/17 if I put in 4.88s. What do people do for a spare who are running 285s? Do you carry a smaller spare under the truck, or have you gone full after-market bumper with tire carrier to carry a full-size spare on the rear bumper? I'm not psyched on either option right now, which is why I'm looking for 4.56 gears. If anyone has info about 4.56 gears for the manual (8.75 inch rear diff) please share!

avitaco: thanks for your info on the 4.88s. Great to hear from someone who has done it. Re-gearing in Jeeps (which I've done) is super common, and Chrysler parts sort of blow, so replacing them is usually a good thing. With Toyota its a little harder choice, since the Toyota gears are so well-made.