New Gears Questioin

[LHB2]

Hello. I will be soon going to 285/70/17 Duratracs, have a '08 4runner V6 (lifted w/ LR UCA's). I have read some feel the power loss whereas other don't, so I was going to pull the trigger on the tires and see how it feels and go from there. Looking for options in gears (assuming I re-gear), I am finding alot of conflicting information, most data I am finding relates to the older generations, etc..,. Some the charts I have found indicate re-gearing from 3.73 to 4.1 would get me back to stock, whereas I have read it needs to be closer to 4.56 (even 4.88's in some posts).

Does anyone have any links that goes into detail about re-gearing the '08 4runner with V6? Looking for general info, optimal ratios, effect on performance, mpg's, towing etc...,.

I am basically just starting to get into the re-gear question and really don't know much about it other than some of the conflicting data I have found so far.

Thanks!

 

[fourwd1]

To correctly answer one needs to know:

1) what size are the original stock tires?
2) What is your stock gear ratio?
c)What transmission do you have?

 

[LHB2]

Sorry for not getting back quicker..., but to answer your questions.

1. Original tires are 265/65/17. Specs at tire rack indicate, new, overall diameter = 30.7", section width = 10.4", tire weight of 37lb. The goodyear duratrac 285/70/17 states a diameter of 32.8", section width = 11.5", and tire weight of 54lbs.

2. Current ratio is stock 3.73

3. Transmission is automatic. I do have overdrive.

Based on some further readings at expeditionportal is sounds like you can get by with the 3.73's but if towing etc.., will want to eventually go 4.56 or 4.88's. Otherwise is sounds like I might loose the use of overdrive on the highway (when towing).

 

[MtnBkr]

Aftermarket does not make 4.10 (at least the last time I checked), so you'll have to go 4.56's at least. 4.88's on 33's are too deep for a daily driver in my opinion.

 

[MtnBkr]

And for what it's worth, I wish I had deeper gears than the stock 3.73's and 285's, even with the V8.

The 285's will kill your mileage with the stock gearing. Plan on 2-3mpg.

 

[CAN-03runner]

Is it a 4x4? I don't think there was a 4.10 available for the front diff on a 4th gen. Maybe this has changed recently if you found some.

33" is the most common up size, but gear changes along with it is not too common. Of the V6 4th gens and FJ Cruisers that I go offroading with, none have changed the diff gears for running 33" tires and complain about power. When they went to 35" a few upgraded to 4.56 or 4.88. Those that didn't mostly notice lack of power when going uphill, but they just live with it since they aren't driving uphill all the time. Offroad, when you go into 4Low, you shouldn't notice an issue.

How heavy do you tow? Most people recomend towing in 4th and not D(overdrive), so not getting into overdrive might not be an issue.

 

[LHB2]

Yes, I have a 4x4 selectable (4x2, 4x4 HI, 4x4 Lo). I typically tow pretty light, I have a 5x8 aluminum trailer that I think weights ~800lbs or so. Typcially will haul an ATV, luggage, tree stands, etc...,. I don't think I ever really had more than 2,000lbs behind me. The odd thing is, I will notice the biggest decrease in mpgs and power with it empty (it doesn't drop much empty vs loaded). I think it mostly has to do with the wind resistance as I have 30" solid sides all around with a 4' stepped ramp on the back and full size tires (not those little pumpkins you see on some trailers).

As far as an MPG hit with 285's, I am expecting the 2-3 drop seems pretty common from what I have read.

I have towed in 4th, just to see what happens, still worse MPG than in OD, but once I get the 285's it might wash out.

I am pretty much set on the 285's (just waiting for funds), will see where to go from there. Funds permitting, it sounds like 4.56's are the way to go. I was looking at ECGS and they have the complete gear set up, anyone have experience on what it takes to install these? I can turn a wrench (installed my lift kit, UCA's, changed sparkplugs, differential oil, etc...,). Would installing the complete gear set up be something left to the professional?

Cost for the complete 3rd is $610 and the reverse clamshell is $550.

 

[t4rbama]

Interested to see how this pans out for ya. Keep us updated with what you end up doing about the gearing! I'm running 285/75R17s on my '06 SE. Despite the larger than normal upsize I'm happy with the change, it fits the lift on my rig well. However, I do notice a good bit less power, especially while towing. I would assume switching out the gears would run about a grand, seems like every mod I do to my 4th gen is...

 

[aha2988]

Yes, I have a 4x4 selectable (4x2, 4x4 HI, 4x4 Lo). I typically tow pretty light, I have a 5x8 aluminum trailer that I think weights ~800lbs or so. Typcially will haul an ATV, luggage, tree stands, etc...,. I don't think I ever really had more than 2,000lbs behind me. The odd thing is, I will notice the biggest decrease in mpgs and power with it empty (it doesn't drop much empty vs loaded). I think it mostly has to do with the wind resistance as I have 30" solid sides all around with a 4' stepped ramp on the back and full size tires (not those little pumpkins you see on some trailers).

As far as an MPG hit with 285's, I am expecting the 2-3 drop seems pretty common from what I have read.

I have towed in 4th, just to see what happens, still worse MPG than in OD, but once I get the 285's it might wash out.

I am pretty much set on the 285's (just waiting for funds), will see where to go from there. Funds permitting, it sounds like 4.56's are the way to go. I was looking at ECGS and they have the complete gear set up, anyone have experience on what it takes to install these? I can turn a wrench (installed my lift kit, UCA's, changed sparkplugs, differential oil, etc...,). Would installing the complete gear set up be something left to the professional?

Cost for the complete 3rd is $610 and the reverse clamshell is $550.

your headed in the right direction my friend East coast gear supply is the shit! and if you can install a lift kit you can bolt these things in.

your going to have to completely disassemble the front axle from the truck and drop that assembly down. on the rear you'll just have 4 bolts on either end of the axle shaft take these loose then unbolt all the retaining nuts on the rear third member and pull it out.

bolt in the new third member, reassemble the axle hub assemblies to the axle.

on the front IFS diff assembly your going to unbolt the passenger side axle tube and half shalf from the IFS diff housing, disconnect your breather tube then assemble the two items that come off your old diff to your new diff and reassemble the front axle

be sure to disconnect all your ABS sensors and place them in a safe place the sensors and wires are both costly to damage.

you'll need red RTV sealant to reassemble the axle tube to the IFS housing you can get the paper gasket for the rear but I just used RTV instead.

run the new gears for about 500 miles avoiding highway speeds for extended time periods (can create lots of heat in the initial break in period) then change the fluid the new gears are now broken in and ready to haul anything you need.

also which ever gear oil you decide to run (I use lucas 85w140) get about 12 bottles of it or a case from ECGS you'll use most of it by the time you get through the break in period and then have a bottle or two maybe left over for the next go around whenever you decide to change the gear oil again. (I initially purchased 8 bottles, and wound up using about 10.)

 

[lehiguy]

THe FJ Cruiser came with a lower axle ratio IF you got the six-speed (3.90 vs. 3.70). It was marginally lower, but that would be all that's required to do what you're doing. Mathematically it would compensate for about 1.5" in increased tire diameter.

 

[LHB2]

Thanks everyone for the info. Will let you know what I end up doing..., after reading another thread I may now consider the goodyear MTr kevlar in 275/70 17 or 255/70 17 so that may change things a bit. Seems they might be a little better fit (and I would still be able to get a spare in the original location. If anyone has any experience with the MTr has DD, snow/ice, wear performance, etc..., I would love to hear about it.

Looking to pull the trigger on the tires end of Feb or begining of March.

 

[Quint]

I have an 05 V6, I got diffs from ECGS. 4.56 front and rear with an ARB in the rear. I feel this was the best mod I've done to the truck. I was running 285/70/17 BFG mud terrains for a while, the gear ratio change definitely helped out with how the truck drove with that size tire, it didn't hunt for gears anymore when getting on highways(I especially noticed when going uphill). And it felt like the truck was back to its original power after the gear change. The lower gears also greatly improved the offroad capabilites when in 4lo, i spend a lot less time with my foot on the brake, the truck crawls nicely. I have since moved up to 305/70/17 Goodyear mt/r's (great tire by the way, I highly recommend them) and am still happy with the 4.56 gears.

 

[lehiguy]

I have an 05 V6, I got diffs from ECGS. 4.56 front and rear with an ARB in the rear. I feel this was the best mod I've done to the truck. I was running 285/70/17 BFG mud terrains for a while, the gear ratio change definitely helped out with how the truck drove with that size tire, it didn't hunt for gears anymore when getting on highways(I especially noticed when going uphill). And it felt like the truck was back to its original power after the gear change. The lower gears also greatly improved the offroad capabilites when in 4lo, i spend a lot less time with my foot on the brake, the truck crawls nicely. I have since moved up to 305/70/17 Goodyear mt/r's (great tire by the way, I highly recommend them) and am still happy with the 4.56 gears.

305? That's a big arse tire for a 4th gen. What did the 4.56s do to your mileage?

 

[aha2988]

I'm running 305's as well with 4.56 gears. I oddly enough after re-gearing I didn't see much change in miles per gallon.

 

[Quint]

Yeah same here, I'm probably averaging 15-16 mpg.

 

[CAN-03runner]

Thanks everyone for the info. Will let you know what I end up doing..., after reading another thread I may now consider the goodyear MTr kevlar in 275/70 17 or 255/70 17 so that may change things a bit. Seems they might be a little better fit (and I would still be able to get a spare in the original location. If anyone has any experience with the MTr has DD, snow/ice, wear performance, etc..., I would love to hear about it.

Looking to pull the trigger on the tires end of Feb or begining of March.

MTR are muds, the type of tire that is not usually very good street driving on ice and snow since they have little sipping, they freeze up and get rock hard. Not good for stopping or turning on ice. I used my mtz for one winter. Forward motion, no problem.but I often ended up past the stop sign even if i drove slow to compensate.

Goodyear duratracs look agressive, and from my buddies that have them i'm told is great on ice, since they are an AT with a mountain snowflake symbol.

 

[montana_jeepn]

I was doing some searching and found this post.

I have a 05' Sport with V8 and 3.73's. I am running LT275/70r17 and don't really plan on going any bigger, maybe a 33" someday, but very doubtful.

I've been getting about 13MPG with factory bumpers/skid plates. The acceleration is okay, but not as good as she was with factory sized tires. Which should I go with? 4.11 or 4.56?

I want max power and acceleration without crossing the line and hurting my highway mileage by running to high of RPM's. She is used 90% of the time on pavement.

Mods so far are aFe Stage 2 CAI, Gibson catback, and URD MAF calibrator. Next will be headers and possibly a supercharger in the future.

Can the speedo be recalibrated?

Thanks.