Axle Gear Ratio's

[Dieselchessy]

1998 SR5, 3.4L, 5 spd manual

Currently I'm running 4.10 gears and 265/70R16 (30.61") tires.
The reason I looked into gears is because first and second gears in my rig seem a little high. Second gear will lug below about 1500rpm if your not easy on the throttle, and first will do the same if you get into it. Second gear is too high for low speed stuff like round-a-bouts, parking lots, rolling through stops, ect. All those maneuvers where your almost idling in second but going too fast to want to drop into first. When towing speed bumps, round-a-bouts, parking lots, ect. are a first gear affair.

Just like everyone tire size will go up, not down. I don't plan to exceed 33".
My rig is a daily driver and I don't rock crawl or anything like that. Just hunting, fishing, and camping.

I ran the numbers and thought others might be interested. I validated the calculator by comparing to my current actuals. It was spot on.
Gear Ratio Calculator

Conclusion:
4.56 with 32.24" tires will match factory ratios for 4.10's and 28.29" tires.
4.56 with my current 30.61" tires will have me running 3K at 70mph (doable).
4.88's would need 33"+ tires to match factory ratios.
4.56 seems like the ticket for the 5 speed manual V6 combo with 32-33" tires.

Door sticker tire size Target tire size
225/75R15 (28.29)4.10 275/75R16 (32.24) 4.56
Road speed at given RPM in miles per hour
Gear 1500 2000 3000
1 8 11 16
2 15 20 31
3 22 29 44
4 32 42 63
5 38 50 75
R 7 10 15

current tire size
265/70R16 (30.61) 4.10 285/75R16 (32.83) 4.30
Road speed at given RPM in miles per hour
Gear 1500 2000 3000
1 9 12 18
2 17 22 33
3 24 32 47
4 34 46 68
5 41 54 81
R 8 11 16

265/70R16 (30.61) 4.56 285/75R16 (32.83) 4.88
Road speed at given RPM in miles per hour
Gear 1500 2000 3000
1 8 10 16
2 15 19 29
3 21 28 42
4 30 40 60
5 36 48 71
R 7 9 14

265/70R16 (30.61) 4.30 285/75R16 (32.83) 4.56
Road speed at given RPM in miles per hour
Gear 1500 2000 3000
1 8 11 17
2 15 21 31
3 22 29 44
4 32 42 64
5 38 50 76
R 8 10 15

 

[phattyduck]

You need to completely ignore the door sticker for OEM tire size. You likely had a 16" wheel truck (265/70-16 tires) despite what the door sticker says. It was very rare for 4WD's to come with the 225/75-15 OEM tires.

Parking lots are always a balancing act between 1st and 2nd with every manual trans vehicle I have owned...

-Charlie

 

[Dieselchessy]

Wouldn't the door sticker indicate the factory engineered setup for the vehicle?

 

[phattyduck]

Wouldn't the door sticker indicate the factory engineered setup for the vehicle?

You'd think, but not in this case. My '97 parts truck had the 15" wheel info on the sticker and was a 16" wheel truck. Even looking up the vehicle information on the public-facing Toyota website shows 15" wheels for that truck - Vehicle Specification | Toyota Owners (it is hidden in one of the packages that the truck had). The only place to find that the truck really did have 16" wheels from the factory would have been an original window sticker or a VIN lookup on the TIS system.

If you still have stock brakes, you can check the diameter of your front rotors to check if you have a 15" or 16" wheel truck. 318mm (12.5") = 16" wheels, 297mm (11.7") = 15" wheels.

As another data point, normal V6 auto 4WD trucks (4.10 gears) reach 2000 RPM in top gear (OD) around 65mph. You are already spinning higher than that with your current setup... (normal for Toyota manual trans vehicles of that era)

-Charlie

 

[Dieselchessy]

Regardless of door stickers and factory/dealer options I'm thinking lower gears are going on my list of future mods and 4.56 will likely be the ratio.

 

[Rolling_Thunder]

I am literally running the same set up - 5 speed, 4.10s, and 265/70/16s

My truck runs just fine - very little lugging unless I am say in 3rd gear at 1000rpm and trying to accelerate. I did the 5 speed swap and decided to keep the 4.10s because they worked so well with the set up - I averages 23mpg on my recent cross country trip carrying about 600lbs of crap with me -

I wonder why your set up seems more tempermental than mine

 

[JZiggy]

Unless you're planning on 33" tires I'd stay below 4.56. My truck is geared 4.56 with 265/75R16 tires and a 5speed BUT I am a 3RZ. This setup is even a shade overgeared -- but I prefer that to being undergeared. The 265/70R16 and 4.10 combo tends to work well with most rigs especially the 3.4L that has a decent increase in torque and HP over the 2.7L.

 

[gamefreakgc]

You might want to also run those calculators at whatever speed you top out on in your area on the highway. For me, that's around 70 MPH. That's around 2200 RPM with the 4-speed auto, with 4.56's it's around 2500 RPM and with 4.88's it's pushing 2700 RPM. The question should be, can you tolerate the engine or exhaust note of your vehicle cruising at highway speed on a long road trip? My last Toyota was overgeared for the tires it had and spun at around 3000 RPM in 5th on the highway, it got a bit noisy.

I also think the gearing is too much, but on my auto. 1st gear on the 5-speed or something close is what I'm after. Having it re-geared is pricey though so not on the table right now.

 

[Dieselchessy]

I am literally running the same set up - 5 speed, 4.10s, and 265/70/16s

My truck runs just fine - very little lugging unless I am say in 3rd gear at 1000rpm and trying to accelerate. I did the 5 speed swap and decided to keep the 4.10s because they worked so well with the set up - I averages 23mpg on my recent cross country trip carrying about 600lbs of crap with me -

I wonder why your set up seems more tempermental than mine

Never seen 23mpg with a v6 3rd gen. I get 17 to 18 pretty well every tank on all 3 I’ve owned.

Your rig doesn’t ping if you get into the throttle below 1400 rpm in all gears but first?

I’ve got to run first up to 3k before shifting, drops to 1500 in second, unless I’m going real easy.
If I shift at 2500 rpm then it will ping unless I baby second up till 1400rpm or so.

I’ve owned 2 of these v6 5spd and per memory they both acted this way, though this one may be worse.

Acts a bit like the timing is too advanced.
Real peppy in all gears. Makes the auto tranny rigs feel like slugs.

It’s done this through;
2 engines
Replaced injectors
Throttle body
Throttle position sensor
Fuel filter
Plugs (dual electrode)
Wires
Coil packs

Things I haven’t addressed:
Fuel pump
O2 sensor
MAF (I’ve cleaned it)
???

 

[rallypoint_1]

Running 4.56’s on V6 AT with 31’s” 70 mph is about 3k rpm. Not really screaming but definitely higher than the 3.73 gears. Love it!!!

 

[19963.4lsr5]

It my be time to run some combustion cleaner through it.

You either have carbon buildup causing hot spots or you have a injector not flowing properly and it’s leaning out causing the pinging.


Sent from my iPhone using Tapatalk

 

[JZiggy]

Properly running rigs shouldn’t ping above like 800rpm. Maybe if it was a Honda...

 

[Dieselchessy]

I’ll keep working through the laundry list of maintenance items. I’ve got to catch up with 200k of me not owning it.

Have a new Denso o2 sensor I
need to install. Current readings look decent, will be interested to see how the new one reads.

 

[Dieselchessy]

New O2 sensor is in. Old one didn’t look that old and was a Toyota unit. New one is a Denso. The readings seem to jump around a bit more with the new one and maybe the high and low are more extreme.
Ran it about 30 miles and it seems to run about the same.

 

[phattyduck]

Never seen 23mpg with a v6 3rd gen. I get 17 to 18 pretty well every tank on all 3 I’ve owned.

Your rig doesn’t ping if you get into the throttle below 1400 rpm in all gears but first?

I’ve got to run first up to 3k before shifting, drops to 1500 in second, unless I’m going real easy.
If I shift at 2500 rpm then it will ping unless I baby second up till 1400rpm or so.

I’ve owned 2 of these v6 5spd and per memory they both acted this way, though this one may be worse.

Acts a bit like the timing is too advanced.
Real peppy in all gears. Makes the auto tranny rigs feel like slugs.

How many manual trans vehicles have you owned? I haven't owned one yet that doesn't want to be above at least 1800 rpm when accelerating. Stop lugging that thing around.

The auto will downshift if you get on the gas and will keep RPMs above 2k while accelerating. Even cruising, it is hard to get the ECU to shift down to 1500 rpm unless you are coasting. You should be doing the same with the 5-speed. Stop treating it like a diesel engine (assuming that's where you get your user name?). Gas engines need RPMs to work well - keep it above 1800 RPMs unless you are coasting to a stop (and yes, that means going above 3k rpm in 1st fairly regularly!).

Also, the knock sensor is ignored below something like 3k rpm. The engine still shouldn't be pinging down there though (well, without a supercharger). You might have carbon'd up cylinders or something. Try running 89 or 91 octane and see if the pinging goes away, then figure out how to solve the issue.

-Charlie

 

[Kanoe]

My old 4AFE alltrac corolla pinged like a bugger. I started frequent sea-foam through the throttle body treatments and it improved a lot, really a lot. Mind you that car was at about 350,000 at the time. Likely very carboned.

 

[Dieselchessy]

How many manual trans vehicles have you owned? I haven't owned one yet that doesn't want to be above at least 1800 rpm when accelerating. Stop lugging that thing around.

The auto will downshift if you get on the gas and will keep RPMs above 2k while accelerating. Even cruising, it is hard to get the ECU to shift down to 1500 rpm unless you are coasting. You should be doing the same with the 5-speed. Stop treating it like a diesel engine (assuming that's where you get your user name?). Gas engines need RPMs to work well - keep it above 1800 RPMs unless you are coasting to a stop (and yes, that means going above 3k rpm in 1st fairly regularly!).

Also, the knock sensor is ignored below something like 3k rpm. The engine still shouldn't be pinging down there though (well, without a supercharger). You might have carbon'd up cylinders or something. Try running 89 or 91 octane and see if the pinging goes away, then figure out how to solve the issue.

-Charlie

I think your confusing me describing a symptom(?) of my engines operation with me actually driving the vehicle is some manner. Just because I know my vehicle pings below 1500 doesn't mean that's the rpm range I typically operate it at.

I'm of the opinion that my engine isn't running as well as it should. I believe the pinging is a symptom of the issue. Also the engine doesn't seem as smooth around 1000 rpm as it should. Its smooth at 700 and smooth at 1200 but between about 800 and 1100 its a little rough.

I'll work may way through the normal PM items and expect to resolve the issue while doing so.

I have ordered the air box, resonator, and bellows to convert over to the 99+ style intake and will replace the MAF.
I have cleaned the throttle body but haven't removed the IAC and done a thorough clean. I have the IAC gasket and throttle body gasket on deck ready to do that.
I replaced the O2 sensor. The pinging seems to be reduced slightly, but right now I have the tank filled with Chevron premium and 2 bottles of seafoam so its hard to say.
I don't expect much from the Seafoam as I just installed this engine(JDM) and I cleaned the chambers pretty well prior to install. The other engine exhibited these same symptoms as well. I was hopeful they were related to the head gasket leaking coolant, but it doesn't seem so.

Due to having 2 engines exhibit the same symptoms I expect they are related to one of the components not changed during the engine swap.

 

[sbrkwc]

I have a similar setup as a daily driver (Pacific Northwest Region), with overland equipment mounted on it:

98 SR5 V6 Manual with OEM Rear E-Locker
226k Miles
3" lift
running just under 32" tires
-235/85R16 during non-Winter months
-265/75R16 during winter months for more traction

Just did an engine overhaul, and cleaned up anything that needs to replaced, did find the engine run smoother in higher RPM, esp in 2nd 3rd gear.

I estimate I have added roughly 200 lbs (front) and 300lb (rear) of overland hardware to the vehicle. Usually carrying 1 adult passenger on overland trips. I find my 4th gear is lacking power/torque, especially staying at 60mph uphill to the mountain and ski hill.

Considering/researching gear ratio change to 4.56, most of the discussion threads I read through talked about tire size, but not on weight and tire width..

Questions to the forum:
a) Wonder if anyone knows much about gear ratio on added weight and tire width ?
b) If choosing Nitro gear, any particulars I need to pay attention to ?
c) Anyone in Seattle area knows a good shop for re-gearing ?



KW