I think a 6 speed auto would be the sweet spot rather than the 4 speed autos we have. Technology wasn't around for that back then, but it sure would have been nice to have a lower first gear ratio, 2 overdrives, and a much wider gear ratio spread.
4.56 gears better than 4.88 if used a lot on the freeway?
- Thread starter Option01
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I think a 6 speed auto would be the sweet spot rather than the 4 speed autos we have. Technology wasn't around for that back then, but it sure would have been nice to have a lower first gear ratio, 2 overdrives, and a much wider gear ratio spread.
First off, howdy neighbor! (I live in Fair Oaks)
Yeah, that's good advice about being careful regarding the 5-speed vs automatic. I think some of my early concerns about 4.88 came from old posts that were talking about 5-speeds and/or 4 cylinder motors. That's part of the reason I started a new thread: to try to get input specific for my vehicle/usage.
I think you're right about the stock gearing and almost wonder if the drivetrain was dialed in based on the base 28" wheel size even though most 3rd gens seems to have been sold with the 31" option. Or maybe it was done that way to help it score a little better fuel efficiency for the window sticker.
Wow, 5.29 on stock tires! That's going to be pretty aggressive. I assume you won't be using your 4Runner much on the freeway?
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Yeah, I guess you're right that the 33" tires combined with 4.88 gears is pretty close to the stock 31" tires with 4.30 gears. Compared to that stock setup, the 4.88 would be roughly 125 RPMs higher at 65mph (2300rpm) and the 4.56 would actually have run 25 RPMs lower (2154rpm).
Thanks for the excellent advice! I'm friends with the prior owner and we've both kept up with the maintenance so I assume it's running well. Plus, it only has 140k miles and the smog tests always come back super clean (the techs are usually surprised how clean) so I suspect that's another good sign about the state of the motor. However, I don't know that anyone has ever looked at the throttle cable so that might be worth checking out.
A big part of the reason for re-gearing is that I want to put lockers on the front and rear so it makes sense to do it all at once.
Regarding the tire pressure, I'm running Duratec 285/75R/16 which are LT rated and I'm not 100% sure what psi I should be running. The tire store put them at 35psi and that seems to be in the ballpark for what other people are doing based on some google searches.
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Another good point. Maybe it's just unrealistic for me to expect a heavy truck to accelerate uphill in overdrive. It just currently feels like I'm stuck in 4th with no power unless I floor the gas pedal to get it to drop into 3rd at which point it jumps 800rpm and starts moving. It'd be nice if I could get away from those Jekyll/Hyde extremes.
I ALWAYS recommend that people with larger than OEM tires or higher capacity rated tires (LT or load range D/E/F) chalk test their tires to find the best psi for full engagement across the tread blocks. I've had customers complain of a rough ride in their light duty trucks (1500) that are running load range E tires at 80 psi. At that pressure with such little weight you will feel every crack in the road and have a terrible and small contact patch.
THANK YOU! I was really hoping to hear from some people who have the same drivetrain and had upgraded to either gear size.
Personally speaking, I'm not too worried about it being "quick around town" but its very interesting to hear that you're still dropping out of OD to climb long hills. I wonder if the extra 140-160rpms that the 4.88 gears would give at freeway speeds would allow you to stay in OD? If not, that might push me a bit closer to the 4.56 gears. My reasoning is that if I'm going to be running in 3rd gear the whole way up the mountain either way, I'd rather do it at 2800-3300rpm than 3000-3500rpm
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That sounds like a really good idea. I suppose I should probably do the test unloaded as well as fully loaded to get appropriate pressures for each scenario?
It would probably be a good idea if your cargo or trailer tongue weight is a couple hundred pounds or more.
Cree
New member
Actually I'm wrong. I did my calculations off stock 15s. 4.88s would give you 4.55s on 285s. 4.56 would be a 4.25.
I use this site.... TireSize.com - Compare Tire Sizes, Specs, Prices & more
I've been meaning to do this, even have the box of chalk out! Thanks for the reminder!
Option01, in the Sierras around Bridgeport around 7-8k ft or so my hill climbing is absolutely atrocious and I've been trying to decide how to fix it. I've considered re-gearing, charging, etc. I also researched recently that URD has a MAF sensor calibrator to trick the ECU of how much air is coming in. I haven't bought or tried yet, but my theory is that the truck's AFR is off at that altitude and with this calibrator it *might* get everything back into equilibrium. It's a spitball theory, but I'm planning on trying it before starting the camping season next year.
Interesting idea! I hope you'll share your experiences here if you go that route. No matter what gearing I go with, something that helps with altitude would still be a great addition.
Interesting! So going with a 4.56 gear ratio on my 285 tires would be roughly equivalent to the stock 265 tires with the 4.30 ratio commonly found on the stock lockers. Or at least equivalent if you ignore the extra weight and friction of the 285's lol.
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I went through this exact situation a couple years ago. I have added weight, winch, sliders, rack, skids. Hills or a head wind would kill any power I had. I too would travel 2-4 hours on highway to get to trails and camping. I started out with 255/85/16 and now I'm at 285/75/16. I decided with 4.88 which I'm glad I went with, but the truth is, these runners just dont have the power to go up every hill with ease. I'm even supercharged with smaller pulley, 7th injector and I have times that i kick it out of over drive on long steep climbs. Dont think that gearing is going to solve all the problems. It can help in certain situations. I run around 2600/2650 rpm at 70 on speedo which is 74ish on gps. 4.56 and 4.88 rpm difference is not very much, I dont even give a second thought nowadays of the higher rpms.
Seriously consider the weight of the tires you are getting. Load E is great in all, but is it overkill for what you are doing? Even load E tires of the same size between brands can differ 5+ pounds per tire. Just realize that adding all this weight and size increase is going to make your runner slower. I found it was better to take it a little slower and stay out of over drive for a lot of the climbs. Overdrive kept on during steep climbs increases my transmission temps very quickly. As good practice I dont let the tranny searching for gears by turning overdrive off.
If i had to do it again, I'd kept the 4.88s and only installed a rear locker and not on both axles. In fact if I had to do it all over again, I'd probably get a gx 460/470 with a V8. I love my 3rd gen, but I've always been underwhelmed with the power and that's just having too high of expectations, it's a 90's V6 engine. Curious if you are going to lock the front and rear when you regear?
Edit: just to be clear, I'm in altitude that ranges 4000-10000 ft often on my trips so that also contributes to less power.
Seriously consider the weight of the tires you are getting. Load E is great in all, but is it overkill for what you are doing? Even load E tires of the same size between brands can differ 5+ pounds per tire. Just realize that adding all this weight and size increase is going to make your runner slower. I found it was better to take it a little slower and stay out of over drive for a lot of the climbs. Overdrive kept on during steep climbs increases my transmission temps very quickly. As good practice I dont let the tranny searching for gears by turning overdrive off.
If i had to do it again, I'd kept the 4.88s and only installed a rear locker and not on both axles. In fact if I had to do it all over again, I'd probably get a gx 460/470 with a V8. I love my 3rd gen, but I've always been underwhelmed with the power and that's just having too high of expectations, it's a 90's V6 engine. Curious if you are going to lock the front and rear when you regear?
Edit: just to be clear, I'm in altitude that ranges 4000-10000 ft often on my trips so that also contributes to less power.
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Wow, thank you for sharing your experience/insights in detail! Hearing how much you've done to increase power and that you're still not fully satisfied is good for me to hear so that I set appropriate expectations regarding any future mods. As far as my expectations for re-gearing, extra power was one motivation but I was also interested in reducing strain on the drivetrain and taking the opportunity to add lockers. Sounds like the difference between 4.56 and 4.88 is not that big from any metric so while re-gearing is expensive, I'll probably be fine with either option so I shouldn't stress out too much.
Your post has also reinforced something that came up a little earlier. No matter which gear ratio I go with, I'll probably need to keep the truck in 3rd when going into the mountains both for power and for the good of the transmission (good to know that 4th spikes the temps in that scenario). And if I am going to be in 3rd all of the way up, maybe I should go with the 4.56 ratio so that I'm at 2800-3300rpm rather than the 3000-3500rpm I'd get with the 4.88. As far as altitude is concerned, our adventures pretty much always take us to the 4,000 - 6,000' elevation and my truck theoretically weighs a bit less since I don't have a winch nor aftermarket skids so those two factors might also help me get by with the 4.56 ratio.
I already have the larger tires (Duratec 285/75R/16) and according to the Goodyear website, they weigh 55lbs each. My understanding was that these were on the lighter side for E tires but I'm certainly no expert on that. You're probably right that they might be overkill but a friend had them on his 3rd gen and basically never got stuck when we'd go wheeling in the snow. I guess I just got them stuck in my mind as what I wanted without doing enough research lol.
To answer your question. I was planning to lock both the front and rear. Initially, I was mostly interested in doing the rear only but adding a locker to the front during a re-gear just seemed like an obvious choice since I had the budget for it. I'm curious why you'd skip the front locker if you had to do it again? I know the fronts are kind of weak but I don't expect that I'd use it very often and would go extra easy on it. Or was there some other reason?
gamefreakgc
Elite Member
This is the 4Runner mecca of Norcal for sure. Lots and lots of us around here!
I do plan to still drive it on freeways. I had a custom exhaust done a few years ago and it is pretty loud around 2000-2200 RPM. Increasing the RPM will actually make it quieter... and yes, the goal is aggressive. I hope to get this sucker on a 1/4 mile track when it's all done.
I wouldnt be too concerned about the higher rpm in 3rd gear for shorter period of times. It's not going to make much of a difference on wear. These engines can easily take it. I'm pretty sure I would have been disappointed with 4.56 gears.
I was in the same situation when upgrading gears, while I'm in there, I'll just throw in a front locker at the same time and be duel locked for those situations where I will need one. Well that day never really happened. It's purely subjective and in my case there wasn't any need for a front locker. These rigs are capable with a rear locker and honestly I dont put myself in situations where I need to be double locked since I solo overland most times and it's not the ideal situation to grenade the front end in the middle of nowhere. IFS doesn't play nice with a locked front if you are not careful. Hell, when I lock my front, going straight and turn slightly on dirt road you can feel the tension in the front end. You can accomplish a lot with a open diff or just a rear locker. If you are doing a lot of wheeling right now and consistantly getting stuck with open diffs, then I can see improving your rig by adding lockers to get you further down the trail. I never hit the limitations of my driving with a rear locker, even most of the time with open diffs.
I read multiple threads on being fully locked and most of them basically said the same thing, but I was wanting it and I tried justifying it. I suppose that's how you gain experience. At least I know that I dont need a front locker to support my needs now, though it was an expensive lesson which that could have gone into other upgrades. Your needs may be different though that warrant a front locker.
Skid plates/sliders/bumpers have saved my bacon more than my lockers.
gamefreakgc
Elite Member
The MAF sensor calibrator unfortunately won't gain a whole lot of power. You might be able to richen a little bit to gain power while stock but it's not going to blow your socks off. I have a MAF sensor calibrator that I use on my engine but it's supercharged. The real culprit is atmospheric pressure and the lack of oxygen. At sea level, that's 14.7 PSI. At 8000 ft, it's only 10.9 PSI! That's a whole lot less oxygen in your engine making it much slower. Add 500 lbs of people and gear and it's getting even slower. Not much to be done about that.
JZiggy
Senior Member
Limited slip in the front is also a good compromise...
