Should I upgrade to 4.56 or 4.88 Gears

2.7L 4Cyl
4WD
4.10 Gears
Automatic
285/75R16

It's my daily driver and my normal freeway speed is 75MPH-80MPH.
Light truck with minimal weight.
Only off roading is to get to secluded hiking trails/campgrounds or to go shooting far away from civilization.

Should I upgrade to 4.56 or 4.88?

 

4.88s for the auto.

 

You don't say why you think you need to make this change?

Dropping $3k+ on a mod for a 20+ year old truck doesn't seem smart unless you've got money to burn or there's a very pressing need.

 

4.56 will barely be different than 4.10. Even 4.88 is not that far away. What was your stock tire size? You are likely not even fully making up for the change in tire size with either one of those choices. Without any additional information, I’d say 5.29.

 

I'm new to all of this.
I've only had the truck for 8 months.
Is it not needed with the bigger tires?
From what I've been reading, people make it sound like it's needed once you lift it and get bigger tires.
Currently, every trail I've gone on requires me to use the 4WD.
I'm also in Sacramento which is at sea level, so anywhere I go is a 2K-4K elevation drive for about 2-3 hours and I struggle to stay at 55MPH.

 

Your truck has 150hp - gears are not gonna make you fly up the passes at 80. I think you should lower your expectations and enjoy the drive. If you spend a few thousand bucks on this I guarantee you'll be disappointed.

 

Original tire size was 225/75R15

 

Yeah, my local reputable shop wants 3K.
I was thinking I needed it since I'm constantly revving high to go up the mountains.
I average about 14MPG whenever I go up.
Coming back down I average 17.5MPH.

 

3 grand will buy a lot of gas

 

IMO this is a very worthy mod. Putting larger tires on lowered the cruising RPMs quite a bit. Enough to take it out of the engines sweet spot for power and MPGs.

I do not believe you will be dissapointed. Re-gearing will improve the truck's drivability and be way more fun to drive both off road and on road.

 

Mine is an automatic, so I definitely feel it gear hunting.
Sometimes excessively on the steeper inclines.
If I don't do it, will the added stress to the drivetrain eventually cause engine or transmission problems?

 

Possibly. Do you monitor your transmission fluid temps? Any time the trans is not in torque converteer lock-up it is building heat. Too much and you damage the fluid which can lead to trans damage.

Re-gearing will also allow the engine to not have to work as hard. The most immediate benefit is better MPGs and less strain on the engine components.

 

I have no idea on how to do that.
Is that something I should look into/invest if I'm always going up mountains?

 

Don't even consider MPG as a factor. You would most likely be disappointed. I use this web sites gear calculator. Gear Ratio Calculator to Determine tire size change, RPM, Speeds.

 

I hear ya man - I have 5.29s in my 3rd gen. It made some difference but it's all relative.

There's also a difference in investing in a nearly new truck and one that's maybe 25 years old. OP needs an LS swap to cruise the passes at 80, not gears. It's still gonna be a 150hp truck.

 

Here she is.
Exterior and interior, she's great.
Flawless frame, no rust.
Almost everything has been replaced.
OME suspension with Icon Delta Joints.
Even the transmission was replaced 20K miles ago with a 60K used transmission at a Toyota dealership.

I have two newer cars so I don't mind investing money into this truck, it's been quite a hobby.
I've done everything so far and this job would be the first thing that I outsource.

But don't get me wrong, if it's truly not needed, who wouldn't want to save 3K. But if it prevents issues in the future, I don't mind spending it.

I'm only trying to learn from all of you and decide on whether it's necessary or not.

 

I can't tell which model year your truck is other than it has a '98-00' front end. This important because Toyota in their infinite wisdom did not send trans fluid temp info to the early model ECUs. But I seem to recall that changed with either the '00 or the '01 trucks.

I can only speak about my '02, but the data coming from the ECU to the OBDII port contains trans fluid temp information that can be read in real time with various devices. I used a Scangauge for a number of years for this purpose, but there are other options like apps for the phone that connect via bluetooth.

Another thing you can do is add an external trans cooler. It will help control those temp spikes that happen when the truck drops out of TC lock-up and over drive on the long mountain grades.

 

It's a 2000.
How can I verify if my ECU has that function before investing on that scanner?

 

I have a 2001 2.7 4x4 auto that I regeared a few months ago from 4.10s to 4.56s. I'm running 265-75-16s. I live in AZ, so 75-85 is the typical cruising speed.

It definitely helped quite a bit. The truck doesn't feel nearly as strained getting up to and maintaining speed, and generally just drives better around town. I can also maintain speed much better on hills. I just took a trip from Tucson to PHX and back and with the new gears, it was the 1st time I was able to hold 80-85 the whole way. Another benefit is that this ratio matches the stock ratio so my speedometer is now correct.

I'd likely go with 4.88s if I were you. I'm at 3k RPM at 85 which is where I wanted to be, but your truck is a little heavier and has slightly bigger tires.

 

There is a lot of info on these 1st gens here on TW. I just did a quick search for "transmission temps OBDII" and came up with more than a few threads where this has been discussed.

Here are a couple of examples:

https://www.tacomaworld.com/threads...al-discussion.551852/page-14898#post-25085435

https://www.tacomaworld.com/threads/scangauge-clear-up-the-trans-temp-myth.430188/