Regear 8-speed from 3.3 to 3.9?

[jamgolf]

I will be getting front + rear lockers for my 2020 LC200 and in the process will getting new front + rear new OE differentials with 3.93 gears. I will be running 285/70R18 tires at 33.98".
I wanted to ask if anyone has either regeared to 3.93 and how you feel about the change in terms of driveability, crawling performance, off the line performance, and cruising performance?

Based on reading other threads about gearing, I understand the 8-speed transmission has a better crawl ratio compared to 6-speed with 4.88. So, I think 3.93 should be a good ratio for 8-speed with 34" tires. The @sleeoffroad built heritage truck which was commissioned by @Eric Sarjeant had 34" tires and 3.93 gears. In the video, Christo mentioned the 3.93 ratio was a good match for 34" tires. Based on these choices made by experts like Christo and Eric, I feel it will be a great long term choice but just wanted to ask what others think about this and if there are any owners who have taken this path and their feelings about the choice.

Thoughts, experiences?

 

[bloc]

What are your other plans for the truck? Bumpers? Roof rack? Traction boards? RTT? Heavy towing?

Ideal gearing depends a lot on how you’ll use the vehicle. If you plan to keep the body stock and sleek which keeps things near stock aerodynamics, you wouldn’t need as much gear as if you were building it out. Think of all that stuff hanging off the truck impacting aero as pulling a big trailer 24/7. You’ll need higher RPMs for a given road speed due to the increased horsepower demands... or at least the whole system will work better that way.

Some guys with built 8spds have gone much further than 3.90s. I’d advise filling out a gearing/speed/rpm spreadsheet similar to what Teckis has done a few times and looking at the rest of your build to determine if those 3.90s will be enough.

One HUGE benefit to 3.9s though.. available in an OEM toyota gear set, which will likely be higher quality than anything aftermarket. Other gears are too.. 4.3 I think is the limit. But if I were considering gears in something I’d plan to keep as long as a new 200, that would be a big factor for me.

 

[jamgolf]

First of all, thanks for your input. I appreciate it.

What are your other plans for the truck? Bumpers? Roof rack? Traction boards? RTT? Heavy towing?

No -> bumpers, roof racks, RTT, heavy towing in the near future
Yes -> skid plates, sliders

Ideal gearing depends a lot on how you’ll use the vehicle. If you plan to keep the body stock and sleek which keeps things near stock aerodynamics, you wouldn’t need as much gear as if you were building it out. Think of all that stuff hanging off the truck impacting aero as pulling a big trailer 24/7. You’ll need higher RPMs for a given road speed due to the increased horsepower demands... or at least the whole system will work better that way.

I will keep the body as close to stock look as possible, which should help aerodynamics. My usage for the vehicle is Do Everything Well. Good acceleration in local duty, relatively efficient and comfortable long-distance road trips, Colorado trails, driving on beaches where permitted e.g. South Padre Island, Utah trails, and sand dunes. My wife has always dreamed about an airstream which I have always resisted, but perhaps in the future that might also be something the vehicle will do.

Some guys with built 8spds have gone much further than 3.90s. I’d advise filling out a gearing/speed/rpm spreadsheet similar to what Teckis has done a few times and looking at the rest of your build to determine if those 3.90s will be enough.

I'll look into that. Actually I do not want to go higher than 3.9 i.e. I don't want to go to 4.3 - I am wondering if 3.93 is going to be too much and mess up the driveability.

One HUGE benefit to 3.9s though.. available in an OEM toyota gear set, which will likely be higher quality than anything aftermarket. Other gears are too.. 4.3 I think is the limit. But if I were considering gears in something I’d plan to keep as long as a new 200, that would be a big factor for me.

OEM gear set is definitely a huge benefit. I want a super reliable and super capable vehicle and sticking to Toyota parts gives me confidence that would be the case.

 

[mcgaskins]

No -> bumpers, roof racks, RTT, heavy towing in the near future
Yes -> skid plates, sliders



I will keep the body as close to stock look as possible, which should help aerodynamics. My usage for the vehicle is Do Everything Well. Good acceleration in local duty, relatively efficient and comfortable long-distance road trips, Colorado trails, driving on beaches where permitted e.g. South Padre Island, Utah trails, and sand dunes. My wife has always dreamed about an airstream which I have always resisted, but perhaps in the future that might also be something the vehicle will do.



I'll look into that. Actually want to go higher than 3.9 i.e. I don't want to go to 4.3 - I am wondering if 3.93 is going to be too much and mess up the driveability.



OEM gear set is definitely a huge benefit. I want a super reliable and super capable vehicle and sticking to Toyota parts gives me confidence that would be the case.

Even fully built on 34s I never felt the need to regear my 16, and I don't think you'll need lockers either. MTS and Crawl is so good on the 16+, I think lockers are overkill. I suggest to do mod your truck with everything you want besides gears and lockers, go wheel it and use it for a month, and then see if you ever wished for them. I'd wager you will not find a single scenario in which you would have been engaging the lockers and highly doubt you'll miss the gears too. You will also be saving a massive amount of money, and I imagine the savings will pay for your entire build of lift, sliders, and skids.

 

[Artie]

I’m watching this thread as it’s very relevant to me at the moment as I’m in the very early stages of a build as well. I initially wanted to regear and lock the rear and front but it would eat far too much budget so I’m gonna do the other stuff I want and just add the rear locker. My thoughts are I can drive it and if it’s something I still feel the need to do I can gear and lock the front later.

 

[jamgolf]

@mcgaskins I have read many of your posts on the topic and you've always maintained that gearing is not needed for 8-speed. Based on some of the videos you posted wheeling your truck I can see that you have done really well without lockers and regearing. I feel most (90%) of that is your skill but some of it (10%) is the MTS. I feel no shame in admitting that I am not as good as you are

There are very few vehicles that have front/center/rear lockers. G-Wagon, Power Wagon and that's about it. For me personally, its something I've always wanted.
So, with this vehicle, I "want" (not need) the lockers, with the understanding of costs involved. But then I don't want RTT, Roof Racks, Lights, Bull bars, Tire Carriers, Bumpers, Fridges, Drawers etc. Just the air lockers

In the 3 weeks I've owned it, have gone to a few trails Rollins Pass, Loch Lomond, California Gulch and the vehicle feels so capable, it does not even need to be in 4Low. This is a contrast to Land Rover LR4 which also has taken me to these trails but Land Cruiser feels like its doing it effortlessly. So you are right about vehicle capability.

 

[mcgaskins]

@mcgaskins I have read many of your posts on the topic and you've always maintained that gearing is not needed for 8-speed. Based on some of the videos you posted wheeling your truck I can see that you have done really well without lockers and regearing. I feel most (90%) of that is your skill but some of it (10%) is the MTS. I have no shame in admitting that I am not as good as you are

There are very few vehicles that have front/center/rear lockers. G-Wagon, Power Wagon and that's about it. For me personally, its something I've always wanted.
So, with this vehicle, I "want" (not need) the lockers, with the understanding of costs involved. But then I don't want RTT, Roof Racks, Lights, Bull bars, Tire Carriers, Bumpers, Fridges, Drawers etc. Just the air lockers

You're definitely giving me way too much credit here! I totally get wanting to build the truck exactly how you want it, and if you ever find yourself in a situation where lockers are the only option, you'll be glad to have it. I think of a winch that way too - pretty rare you ever need it, but if that time comes, you certainly appreciate it. I can only recall one time where I really needed a winch for self recovery (it was a bad situation!), but that one instance has pushed me to always put on the front of just about everything since then.

You mentioned driving on sand, and that is a situation I think being locked might help. I don't have a lot of experience driving on beaches, but I got stuck in some of the softest and deepest sand I've ever driven on a couple weeks ago (steep dunes). The MTS and Crawl were not as effective as lockers would have been IMO, though I did find Crawl works awesome in reverse

 

[jamgolf]

You're definitely giving me way too much credit here!

Some Jeep Rubicon guys that went after you would agree with me
You made it look easy and then those fellas had to follow and struggle with their 37s and lockers.

 

[mcgaskins]

Some Jeep Rubicon guys that went after you would agree with me
You made it look easy and then those fellas had to follow and struggle with their 37s and lockers.

Touche!

 

[Artie]

Mud and sand while towing my overland trailer is why I’m doing the rear locker and considered the front and the gear. Beach driving is a thing as is sudden torrential downpours which can cause significant mud issues when pulling the camper out a narrow road leading to a campsite. Backing out to get a better run at something isn’t as easy with a few thousand pounds and another axle behind the hitch.

 

[TeCKis300]

I'm with @mcgaskins on the need for lockers. That said, I'll try to add some rambling info on the original question.

My opinion with gearing is that the 5.7L doesn't play by the same rules of traditional need to re-gear. I've said it many times, she's a brute. Throwing larger tires on and losing wheel torque effects lesser motors to a far higher degree. Sure, back to back, you'll know she has less gearing, particularly shifts.

I just re-geared with my 6-speed from 3.9 to 4.3, with 33s. Before re-gearing and running 33s, with a 7% gearing deficit, she was still doing great. Doing great even hauling 14k+ worth up rig up the steepest inclines. The only place where I wished for more gearing was on the steepest grades (7%+) where starting from a standstill or at around 25mph in second gear, I couldn't get at the highest output RPM band of the 5.7. The 8-speed will never have this problem even pulling the largest of tires that will fit. To put this into perspective, the 8-speed even with 37s still has more first gear than the 6-speed on stock 31s

Now that I've re-geared to 4.3s (10% better overall gearing than 3.9s, or 3% better than stock), it's a bit more sprightly around town. The 5.7 feels a bored as it seemingly freewheels loafing around. I'd imagine that's how the stock gearing can feel on the 8-speed with its incredible low gearing.

The change from 3.3s to 3.9s would be pretty dramatic. That's a huge 15% change. I'd wager that puts things outside of what's necessary, perhaps into the annoying spectrum unless really really built heavy with huge tires. Those mods would complement a re-gear change like this well. There could be arguments with very big tires, aero losses, and weight that S8 would not be very useful on the highway constantly unlocking the torque converter. Re-gearing would solve that problem. Using sport mode limiting to S7 should also.

Separately, if your goal is to be triple locked...at the moment, it seems re-gearing is the only way to a front locker. The thick crown gear of the 3.3s and the impact to deck height of the diff case are not currently compatible with any lockers on the market.

Only logical solution I see is to go all out with a build including re-gear, locker, armor, big meats, rack ...and Airstream. That's why we're the 21 step 200-series anonymous program.

 

[bloc]

First of all, thanks for your input. I appreciate it.



No -> bumpers, roof racks, RTT, heavy towing in the near future
Yes -> skid plates, sliders



I will keep the body as close to stock look as possible, which should help aerodynamics. My usage for the vehicle is Do Everything Well. Good acceleration in local duty, relatively efficient and comfortable long-distance road trips, Colorado trails, driving on beaches where permitted e.g. South Padre Island, Utah trails, and sand dunes. My wife has always dreamed about an airstream which I have always resisted, but perhaps in the future that might also be something the vehicle will do.



I'll look into that. Actually I do not want to go higher than 3.9 i.e. I don't want to go to 4.3 - I am wondering if 3.93 is going to be too much and mess up the driveability.



OEM gear set is definitely a huge benefit. I want a super reliable and super capable vehicle and sticking to Toyota parts gives me confidence that would be the case.

I would still run the gearing spreadsheet, but here’s my take on it. Toyota tried hard to maximize the mileage of these vehicles, as you’d expect. This means both aero optimization, and gear selection. They likely kept the ratios just in the range to let 3.3s and whatever your 8th speed is punch a landcruiser sized hole in the air at freeway speed, with a slight buffer for gradual hills, loaded heavy, etc. The expectation is if you were towing or taxing the vehicle, you’d downshift, as recommended in the manual.
While your planned build is more sleek than many, It will sit higher than stock in the front, adding some aero drag, and I’d assume you’ll be on LT tires that have increased rolling resistance. Personally I’d want moderately more RPM at cruising speeds, to let the output of the engine reflect the slight increase in hp needed. This has the added benefit of not lugging the engine and making downshifting for gradual hills less likely.
Anecdotally the people in this section seem to report better mileage when they don’t lug the engine, and that plus somewhat similar build plans to yours is why I’ll be installing 4.3s in mine soon, though I have a 6spd.

So I think you are on the right track. Your 8 speed, this great engine, just enough armor to protect against dragging, larger tires, gearing to get the effective ratios back close to stock (but check the numbers for sure) and maybe a little further.. should be awesome.

 

[18Cruiser]

I’m watching this thread as it’s very relevant to me at the moment as I’m in the very early stages of a build as well. I initially wanted to regear and lock the rear and front but it would eat far too much budget so I’m gonna do the other stuff I want and just add the rear locker. My thoughts are I can drive it and if it’s something I still feel the need to do I can gear and lock the front later.

This is exactly what I did about a year and half ago. 34's, rear locker.

I wanted to be triple locked, and could and wanted to spend the $$$ to do it. The shop doing the work convinced me to not do it. Said I could do it later if I really felt the need. Thing is I "wanted" to do it, but I didn't "need" to do it. The times, three times, I have used the rear locker probably could have just used the MTS and crawl, but I had it and wanted to use it. It worked perfectly in the mud and snow, I didn't get stuck (first time) and pulled out a Merc. Sprinter van/camper out of a muddy field (second time). Next time pulled a Suburban out of snow ditch (third time). Like I said, I probably could have gotten by without the rear locker but I had it and wanted to use it.

Sad to say, I don't need a front locker or re-gear...BUT I still want it. Its good to have wants though and probably won't end up getting a front locker. Unless they come up with one that doesn't need a re-gear.

 

[Artie]

This is exactly what I did about a year and half ago. 34's, rear locker.

I wanted to be triple locked, and could and wanted to spend the $$$ to do it. The shop doing the work convinced me to not do it. Said I could do it later if I really felt the need. Thing is I "wanted" to do it, but I didn't "need" to do it. The times, three times, I have used the rear locker probably could have just used the MTS and crawl, but I had it and wanted to use it. It worked perfectly in the mud and snow, I didn't get stuck (first time) and pulled out a Merc. Sprinter van/camper out of a muddy field (second time). Next time pulled a Suburban out of snow ditch (third time). Like I said, I probably could have gotten by without the rear locker but I had it and wanted to use it.

Sad to say, I don't need a front locker or re-gear...BUT I still want it. Its good to have wants though and probably won't end up getting a front locker. Unless they come up with one that doesn't need a re-gear.

I totally here you on the ‘want me factor and see no issues with that. I wanted it as well but my want for other stuff won out to keep the budget inside a livable amount. However, I still want it and I’ll revisit the ‘getting’ part after some real world mileage. My daily driver, which I’m keeping, has 450 HP and a 10 speed trans, I feel like the loss of acceleration is going to keep me wanting that regear.

 

[jamgolf]

2016+ GEAR RATIOS:
First 4.79:1
Second 2.8:1
Third 1.84:1
Fourth 1.43:1
Fifth 1.21:1
Sixth 1:1
Seventh 0.82:1
Eighth 0.67:1
Reverse 3.79:1
Final Drive Axle Ratio 3.3:1

Transfer Case Gear Ratio, low 2.618:1

 

[jamgolf]

Looks like TC low ratio is 2.618:1

 

[jamgolf]

So for 2016+ the Crawl Ratio is:

With stock 3.3 axle ratio:
4.79 x 2.618 x 3.307 = 41.47

With 3.93 axle ratio:
4.79 x 2.618 x 3.93 = 49.28

 

[bloc]

How would freeway RPMs at 70 & 80 compare to stock tires stock gears vs 3.90s and your planned 285/70/18?

 

[jamgolf]

How would freeway RPMs at 70 & 80 compare to stock tires stock gears vs 3.90s and your planned 285/70/18?

With 3.3 Axle ratio, cruising in 8th gear on stock 31.5" tires:
70 mph -> 1651 rpm
80 mph -> 1887 rpm

With 3.93 axle ratio, cruising in 8th gear on 34" tires:
70 mph -> 1823 rpm
80 mph -> 2083 rpm

 

[jamgolf]

@bloc ^ Good question.
A decent bump in crawl ratio and a slight RPM increase when cruising.
If off the line performance is improved (which I feel will happen) - I think I'll be a happy camper.