Anyone ever re-geared a stock truck?

Anyone ever done 4.88 or 5.29’s on a stock truck? I’m running 5.29’s on 34’s and it still feels undergeared. It’s not lack of power or anything. Tows fine and runs great. But I’m curious how it would do with stock size tires. I’m contemplating picking up some used take offs and seeing how it does with those but figured I’d ask if anyone had done it already.

 

I've got a box with 4.88 rear gears in it, just waiting to find a good deal on 4.88 fronts. I'm still on stock size tires (in an E rating) and am debating whether or not to install the 4.88's when I swap out my Auburn for the Torsen unit. My experience may be somewhat atypical as the truck is heavy and tows a lot, but I installed a Whipple at the beginning of the year. So I figure if anybody could use 4.88's on a stock rig it WOULD have been me last year. It certainly doesn't lack for power now, but that doesn't mean it wouldn't benefit from deeper gearing. Just hoping it doesn't ruin my already somewhat-abysmall-but-completely-expected-and-not-complaint-worthy fuel economy.

So I am also curious if anybody else has done 4.88's on a stock truck.

 

I’m wondering if it wouldn’t actually increase the mileage. The gearing in these transmissions is tall from what I remember so adding a better rear end may actually help the truck move out better and keep it in its power range better.

 

Tons of people upgrade gears here. 99% do 5.29s. 4.88 won't be too noticeable since you already have 4.30 gears with tow package.

Search forum. Rare to gain mileage, mostly just get usability and pep. Usually people with large wheels or towing. You need a tune to get the most out of it. You can mimick gears with tow haul and locking truck in 4th.

 

There was a guy on here pulling a 5th wheel that regeared on stock tires but I can’t seem to find the thread now. Can’t remember the title.

I read a handful of posts from Tacoma guys with automatic transmissions on stock tires that did it and loved it. They were all carrying heavy slide in campers or towing all the time.

 

Yes I understand. I have 5.29’s and tuned but larger tires. I’m wondering if people have done gears with just factory size tires.

 

5.29 or 4.88 if running 285/65/20? Don’t think I’ll ever go bigger

 

Found some used stock size tires I’m getting for free from a buddy. Now need to grab some cheap 20’s to mount them on and test my theory.

 

5.29s on stock size tires would make 1st and 2nd gear pretty much useless. You’de be shifting into 3rd at 25 mph and spinning close to 2500 at 70 mph.

 

5.29 gears with 35s ends up being the same effective final drive ratio as 4.88s and stock sized tires believe it or not (4.87 to be precise).

 

Tuning will help on shift points although currently this thing wants to get to 6th gear as low as 35-40 which is hugely irritating. The rpm’s at 70 mean nothing to me. It’s all about engine load that I’m curious on. 2500rpm at 10% load is less work than 1700rpm at 30% load. Also, the tires are free and I can probably find some 20’s for cheap so this experiment won’t cost me much. I’m also curious how towing will be with the bigger gears and smaller tires. Should be significantly better.

 

Correct. My thinking is these trucks are under geared from the factory. So if 5.29’s on 35’s is equivalent to a 4.88 on stockers and it still feels under geared, what would 5.29’s on a stock tire feel like?

This whole thing is purely me being bored and wanting to experiment. I’m also looking into a side exit on the SPD dump exhaust because for some reason I would rather tinker on this than finish the two other project vehicle builds I’ve got going on.

 

High rpms translates to heat in the motor and transmission. If running short gears were more ideal in an oem setting, it would be a common thing. But running through all the gears before you reach highway speed leads to a transmission that won’t hold a single gear for any period of time and all this does is translate to heat which is a transmission killer. You’re basically going to be trying to daily a rig made to go slow with high rpms, like a rock crawler.

Imagine driving constantly in 4L.

 

Out of curiosity I wanted to compare the equivalent drive ratio in each gear combining the final drive ratio (gears) with the ratio for each transmission gear compared to other truck 6 speed combos out there.

For a tundra with stock tires on 4.88 gears (or 35s on 5.29s) they are as follows:

Ratios with 4.88 Final Drive:

• 1st Gear: 16.263
• 2nd Gear: 9.565
• 3rd Gear: 6.606
• 4th Gear: 4.880
• 5th Gear: 3.550
• 6th Gear: 2.868

For a 2022 Silverado 2500 with the 6 speed trans and 4.10 gears the equivalent ratios are as follows:

Effective ratios with 4.10 gears:

1. 1st Gear: 4.03 × 4.10 = 16.52
2. 2nd Gear: 2.36 × 4.10 = 9.68
3. 3rd Gear: 1.53 × 4.10 = 6.27
4. 4th Gear: 1.15 × 4.10 = 4.72
5. 5th Gear: 0.85 × 4.10 = 3.49
6. 6th Gear: 0.67 × 4.10 = 2.75

It would seem a tundra with 4.88 gears gets it pretty close to a 2500hd with the 6 speed and 4.10 gears. If I get more time I’d like to compare to other trucks with 6 speeds. The tundra with 4.30 gears and it’s high trans gearing will definitely have a much higher effective gearing by comparison vs the 6L90 with 4.10s.

 

I tow in 5th gear at 70mph with no heat issues so what would the difference be between that and driving with stock size tires in 6th? And again, the truck already goes through all 6 gears before highway speeds so still not understanding the argument. I’m in 6th by 40mph. If anything, the gearing with stock tires will keep the rpm’s up which helps keep transmission pressures up which helps avoid slipping clutches. It also wouldn’t cause me to be bogging the motor down at 1200rpm and trying to accelerate which is also better for the engine and transmission.

 

There is zero benefit to installing that short of a gear and using stock tire size other than getting out the hole a little quicker. These motors aren’t made to make power on the top end. These engines are designed and the gears provided are designed to provide power in the power band of the motor. Youre changing the entire points at which the engine makes power. Youre trying to reinvent the wheel on a 15 year old platform that has proved tried and true. You didn’t just stumble across a game changer lol.

 

That’s where I’m going. I’m just going a little bigger step with the 5.29’s. Be like going to 4.30’s in the HD in that scenario

The stock Tundra 4.30’s leads to these ratios.

First: 3.33 x 4.30 = 14.319
Second: 1.96 x 4.30 = 8.428
Third: 1.35 x 4.30 = 5.805
Fourth: 1 x 4.30 = 4.30
Fifth: .73 x 4.30 = 3.139
Sixth: .59 x 4.30 = 2.537

With the 5.29’s.

First: 3.33 x 5.29 = 17.6157
Second: 1.96 x 5.29 = 10.3684
Third: 1.35 x 5.29 = 7.1415
Fourth: 1 x 5.29 = 5.29
Fifth: .73 x 5.29 = 3.8617
Sixth: .59 x 5.29 = 3.1211

For reference the 2500 HD with 4.30’s.

1. 1st Gear: 4.03 × 4.30 = 17.329
2. 2nd Gear: 2.36 × 4.30 = 10.148
3. 3rd Gear: 1.53 × 4.30 = 6.579
4. 4th Gear: 1.15 × 4.30 = 4.945
5. 5th Gear: 0.85 × 4.30 = 3.655
6. 6th Gear: 0.67 × 4.30 = 2.881

 

I’ve regeared plenty of stock trucks. The result is always good. Plus performance tune to get the most out of every drop of fuel.

 

2500 gassers come with a 3.73. And you’re comparing our dohc 5.7l to a pushrod, single cam 6.6l motor that makes a lot more torque. The 6.6l diesel comes with a 3.73. If all your math made sense, they would have short gears as well.

 

GM does offer 4.10s with the 6.6 gas, which may only be the 3500HD, but it’s all the same truck with an extra overload leaf or something along those lines. They also offered the 4.10 gears with the 6.0 when that was the gas offering. Not to argue what’s right or wrong for the tundra, I’m just stating those facts.

 

I've always regeared my sports cars and never had a downside to any of them. Don't see why this truck wouldn't be any different. Get the rpm's up in the power range of the motor instead of always bogging down below 2000 where it doesn't make any power.

 

completely stock, 488 would prob be great. Any kind of lift, bigger tires, extra weight, or towing, 529 would be the way to go.

 

I’m happy with the 5.29’s and 34’s. Just curious how it’ll be with stock size tires. Certainly not gonna hurt anything to try it.

 

youll have plenty of power. Highway RPM will be higher.

 

I'm curious too as I was planning on regearing mine to 5.29 but will not be able to replace the tires with 34 or 35 right away. I have a 2010 Crewmax 4x4. It has an VF tuner 91 octane with gear lock and direct shift feature. Love those features as you can use a lot of the available torque the engine can produce at that rpm. When the rpm drops to below 1500, then the automatic feature will kick in and will downshift the transmission to the appropriate gear as the ecu sees it. Or you can manually downshift it, which I do most of the time.

I have experimented with the loads on this truck. The typical load that I have put in the bed was 1500 lbs +- some. That's just on the bed. Bags of gravel and broken up concrete. Tires are stock size AT on stock wheels. Drove to uphills and downhills, stop and go, traffic lights. It was heavy. I also disabled the ACIS and by doing that the torque is quickly available.

My shifting rpm for the most part is between 2000-2400 in S mode. Shifting 1-2 is in auto mode most of the time unless I'm waiting on the green light on an uphill, then, I will put it on 1st gear. I do accelerate a bit harder on these low gears. Quicker to get the truck to accelerate to the appropriate speed and then upshift it to maintain that speed, instead of upshifting quicker and trying to accelerate the truck in higher gears. I also watch the rpm's with regards to the vehicle speed. If the rpm is dropping below 2000 and truck is not accelerating that much, I downshift. Sometimes it happens on that uphill. Still got 13-14 mpg on this.

But, yea, try it and see how it works. Try it with the truck unloaded, and heavily loaded.

Now, I reduced the weight as I no longer work and I don't want the truck to be parked with that much weight on the tires ( P rated).

And, now that I'm lighter, I'm using full automatic mode. Nice easy driving. Mileage is now at 12 mpg and no uphills.