Gearing Down a 3 Gen Tacoma

[MarkEva]

As some of you know, my truck has a manual transmission. As such, there is a minimum speed it will go up hill before stalling, unfortunately, that speed is often too fast for some obstacles so my mechanic and I are looking at options. It's a chain drive transfer case that can't be re-geared (sprocketed). I don't want to re-gear the differentials because I use it on the interstate a lot. Options are Doublers like the Taco Box that would require re-doing all the drive shafts, an aftermarket transfer case or an older Toyota transfer case with gears. The mechanic is concerned that a transfer case replacement risks messing up the electronic safety interlocks (which are already a problem).

Any suggestions?

 

[jps8460]

I believe advance adapters makes an adapter plate to swap an atlas tcase into a manual fjcruiser. If memory serves that’s the same trans you have. This doesn’t avoid having to customize some parts, but is a stout and reliable unit that is a full replacement vs adding an additional crawl unit like a taco box or trail creeper.

It’s probably worth mentioning that lengthening and shortening drive shafts is relatively inexpensive.

Regearing your diffs may not be a bad option as it would probably help with low speed manners and the added bed weight.

Be sure and post up what you decide!

 

[DaveInDenver]

The 3rd gen Tacoma uses either an RC62 on the V6 or a R156 with the 4 cylinder.

The FJC would have used the RA60 like the 2nd gen V6 Tacoma.

Also note that the FJC with a 6 speed manual would have a full time lever actuated transfer case (VF4B) while all Tacomas got regular part time with electric shift (such as VF2BM in my 2008).

I don't know what a 3rd gen Tacoma would have, I assume a VF1A and/or VF2BM.

A Tacoma Box is the Cadillac solution. The problem for Marlin is finding enough gear driven boxes to build them. The adapters aren't a big deal other than swapping the 23-spline inputs. Not sure how often Inchworm makes them, although I think they do the build after you order it. So it's just about finding a donor RF1A t-case.

Doing an Atlas would be cool. There's additional factors to consider, mainly in the order the 4WD ECU wants things to happen based on the dial position, the t-case position and front axle actuator. It can be hacked to work, just know it's out there. The Atlas solution assumes I think you're doing long travel or SAS, thus are doing significant mods and probably chucking the stock IFS systems.

I've been thinking about this for years. Nevermind the money issue that holds me back but I'm fairly certain the best (not cheapest) approach for mild 'wheelers like me is a Taco Box, keeping the stock 4WD ECU and electric shift on the rear case.

There's a harness out there to extend the connections to the rear t-case. So you don't have to make any serious or permanent mods to the wiring or ECU functions. Normal 2WD, snowy road high range and stock low range all work exactly the same. You have a high/low manual reduction if you want geared down 2WD or the ultimate low.

Mechanically you find a spot for the front box stick and extend/shorten the two driveshafts. In my truck the front gear box stick will fit up through the small slice in transmission boot, so that's an easy solution. The driveshafts are about the only permanent modification and even that is an improvement. You can remove the carrier bearing and run a one-piece rear driveshaft, which solves a constant headache on these trucks.

It's the least amount of modification for the most gain. You don't have to re-gear axles at all if you don't want in that case.

Although I do still want to do that. Toyota put 3.73 in my truck and stupid ratios in the transmission, 5th gear is kind of pointless. At least with the RC62 4th is 1:1 and you have two O/Ds. In the Tacoma RA60 5th is 1:1 and 6th is 0.85:1, which is great for interstate with 3.73 and 32" tires. But makes crawl more like brisk walk.

It would be so simple with either granny 1st (what's the point of 6 speeds if you don't make either 1st or 6th ultra something?) or a gear-driven case. But no, it can't be easy.

 

[jps8460]

heck yea, thanks for chiming in Dave. Agreed that a crawl box would be the way. While I love Marlin and agree the taco box is ideal. It seems that trail gear often has the creeper boxes on hand. That is definitely the path of least brain damage without regearing diffs.

Edit: looks like the trail creeper stuff is only compatible with the A750F. Taco box it is https://www.marlincrawler.com/product/tacobox-for-2005-6-speed-manual-transmission/

 

[DaveInDenver]

Yeah, Big Mike has a slightly different vision for Marlin Crawler than his dad. He's less dedicated to wacky drivetrain stuff.

The whole market has moved on, it's more progressive/aggressive and focused on newer stuff. It doesn't help that I'm not sure if Inchworm is still around and Advanced Adapter and Trail Gear also aren't interested in the small market for oddball Tacomas. The difference I think in an auto and stick is the spline count. Pretty sure the transmission and t-case adapter plates themselves are the same pattern.

If memory serves though Mark has a 2TR (2.7L) truck with the R156, which might mean it'll very well take the same adapters as the R150/R151/R155 in older trucks.

For example, this is the adapter for a W156, which I figure is the same as the 5VZ/R155 in the older Tacoma.

2.7-liter 2TR manual (IG31)

Marlin Crawler and Inchworm have been working together for well over a decade. As the first exclusive distributor of Inchworm Single & Dual Case setups, we have been supplying our Heavy Duty adapter…

www.marlincrawler.com

I do wonder if this is one option Mark's talking about. Marlin used to sell an adapter that let you use a RF1A (gear t-case) on the back of a R150 from a 3VZ (3.0L) V6. This might work but it would not retain the electronic shift for one, which like I mentioned messes up the timing of the 4WD ECU with respect to it engaging the front drive.

Chain Drive to Gear Drive T/Case Adapter Kit

This Adapter Kit attaches to the front of a 4cyl Gear Drive RF1A Transfer Case, allowing it to be bolted behind the 1988-1995 3.0L 3VZ-E type R150F 5-speed 6cyl transmission. Please note that this Kit…

www.marlincrawler.com

Oh, and don't forget Yodaman.

Built Geared Transfer Case

The take-away for @MarkEva is this isn't really an off-the-shelf thing. You're going to have to get on the horn, talk it through with Marlin or someone else, probably get on some wait lists, track down bits-and-parts and custom assemble it yourself.

 

[brettf]

@MarkEva Mark I'm laughing looking at your signature noting the tires and then "being done". Mostly because I can relate to that and also to looking at options for lower t-case gears all in the same breath. I have a similar setup with a third gen Tacoma and a manual 6 speed v6. I also regeared to 4.88 which helps. I did that early after owning the truck, however, lower gearing at the t-case is something I've been looking at for a while now.

I've been looking at both the TacoBox from Marlin Crawler as well as the Northwest Fab product (Eco Box or EcoCrawler box or something), which I don't believe I've seen mentioned in this thread. Here's a link: https://northwestfab.com/products/eco-crawler-vf4?variant=43226661814435

The TacoBox is something it doesn't feel like M/C likes to sell piecemeal anymore - they'll sell you a built unit, but it still requires work. You have to do the things you've mentioned (changing length of driveline). But also requires swapping the input shaft out of your existing t-case in order for it to accept the output from the TacoBox. You could also buy a t-case from an automatic truck and just use that since it already has a compatible input shaft.

The NWF Product is similar but, well, different. It uses their in custom housing, which hosts the gearing reduction (whereas Marlin uses half of an older gear-driven t-case unit). You have to source guts (planetaries and some other parts) from a chain-driven VF Toyota case, put that into the NWF case yourself, swap the input shaft out of your existing t-case (and replace it with a NWF shaft) and put it all together. Here's a video from a different Toyota application, but concept applies:
View: https://www.youtube.com/watch?v=K9gnTsX45M0
. It's not trivial, but appears doable.

Whether you use TacoBox or the EcoCrawler, you'd still have to figure out the new reduction case shifter, which supposedly is really clean for the TacoBox and pops through a hole you cut in your trans shifter boot. The NWF shifter is less conveniently located from what I've read, but it would have to be close and I'd think you could make it clean through that existing shifter boot.

I don't know if you have the four cyl or six, but you can see both are listed in the NWF material/fitment guide:
https://cdn.shopify.com/s/files/1/0509/2261/9043/files/EcoCrawler_Fitment_Guide_R00.pdf?v=1660254556. Does M/C fit the four cyl? I've never looked for that.

Neither is a turnkey solution, though M/C is closer to one. NWF claims to be stronger/more reliable. I don't know if that's true.

If you go with one or the other, you need to have/get: (I'm sure I'm missing things here)
Marlin Crawler:
TacoBox unit
New auto t-case or new 23 spline input shaft and minor surgery to swap shafts
shifter lever

NWF:
EcoCrawler parts (you don't buy a built unit)
Donor VF case for planetary gears (remove parts, install into EcoCrawler case)
incidental parts for the build (some split bearings, some parts to convert donor to manual shift)
Swap NWF shaft into existing t-case for input
shifter lever

Either requires driveline length changes and perhaps clearance and wiring extensions for actuators, vacuum hoses, shifter accommodation through/into cab and maybe more since I haven't done this (yet?). These both retain your existing case/actuator behind the new reduction case, and as such, you just use the existing "knob" for actuating the standard low/high/4x4. IMO all these are low effort/cost relative to the rest of it and not a big deal.

I like NWF because I believe it may be stronger, slightly more simple, and is shorter in length. I don't like that I'd have to swap input shafts on existing t-case. I don't like that I have to find a good donor case (this seems simple but if you find a manual J shift case you have less to do like converting an electric case to manual etc, but a J shift case is expensive because they are desirable). It requires a lot of work to build the case yourself.

I like the M/C because they've been doing this a while. I like that I can just get an auto case and replace my existing case with that and mount the already built TacoBox unit to that and the trans. I don't like the cost... but I'm not convinced that all said and done that the cost is a big differentiator between NFW and M/C though.

Anyway hope some of that helps... stream of consciousness post here.

 

[brettf]

The take-away for @MarkEva is this isn't really an off-the-shelf thing. You're going to have to get on the horn, talk it through with Marlin or someone else, probably get on some wait lists, track down bits-and-parts and custom assemble it yourself.

I could have saved myself the time of typing what I added, and only quoted the above! But hopefully the NWF info helps.

@DaveInDenver thanks for adding YodaMan info! Something else to look at.

 

[ScaldedDog]

BTW, Inchworm was acquired by Low Range Offroad, which appears to be very closely aligned to Trail-Gear. It's a bummer, as I have one of Jim's blue cases in my 4runner.

Mark

 

[Notyourmomslx450]

BTW, Inchworm was acquired by Low Range Offroad, which appears to be very closely aligned to Trail-Gear. It's a bummer, as I have one of Jim's blue cases in my 4runner.

Mark

Low range is owned by TG as well as All Pro.

 

[Notyourmomslx450]

@MarkEva Mark I'm laughing looking at your signature noting the tires and then "being done". Mostly because I can relate to that and also to looking at options for lower t-case gears all in the same breath. I have a similar setup with a third gen Tacoma and a manual 6 speed v6. I also regeared to 4.88 which helps. I did that early after owning the truck, however, lower gearing at the t-case is something I've been looking at for a while now.

I've been looking at both the TacoBox from Marlin Crawler as well as the Northwest Fab product (Eco Box or EcoCrawler box or something), which I don't believe I've seen mentioned in this thread. Here's a link: https://northwestfab.com/products/eco-crawler-vf4?variant=43226661814435

The TacoBox is something it doesn't feel like M/C likes to sell piecemeal anymore - they'll sell you a built unit, but it still requires work. You have to do the things you've mentioned (changing length of driveline). But also requires swapping the input shaft out of your existing t-case in order for it to accept the output from the TacoBox. You could also buy a t-case from an automatic truck and just use that since it already has a compatible input shaft.

The NWF Product is similar but, well, different. It uses their in custom housing, which hosts the gearing reduction (whereas Marlin uses half of an older gear-driven t-case unit). You have to source guts (planetaries and some other parts) from a chain-driven VF Toyota case, put that into the NWF case yourself, swap the input shaft out of your existing t-case (and replace it with a NWF shaft) and put it all together. Here's a video from a different Toyota application, but concept applies:
View: https://www.youtube.com/watch?v=K9gnTsX45M0
. It's not trivial, but appears doable.

Whether you use TacoBox or the EcoCrawler, you'd still have to figure out the new reduction case shifter, which supposedly is really clean for the TacoBox and pops through a hole you cut in your trans shifter boot. The NWF shifter is less conveniently located from what I've read, but it would have to be close and I'd think you could make it clean through that existing shifter boot.

I don't know if you have the four cyl or six, but you can see both are listed in the NWF material/fitment guide:
https://cdn.shopify.com/s/files/1/0509/2261/9043/files/EcoCrawler_Fitment_Guide_R00.pdf?v=1660254556. Does M/C fit the four cyl? I've never looked for that.

Neither is a turnkey solution, though M/C is closer to one. NWF claims to be stronger/more reliable. I don't know if that's true.

If you go with one or the other, you need to have/get: (I'm sure I'm missing things here)
Marlin Crawler:
TacoBox unit
New auto t-case or new 23 spline input shaft and minor surgery to swap shafts
shifter lever

NWF:
EcoCrawler parts (you don't buy a built unit)
Donor VF case for planetary gears (remove parts, install into EcoCrawler case)
incidental parts for the build (some split bearings, some parts to convert donor to manual shift)
Swap NWF shaft into existing t-case for input
shifter lever

Either requires driveline length changes and perhaps clearance and wiring extensions for actuators, vacuum hoses, shifter accommodation through/into cab and maybe more since I haven't done this (yet?). These both retain your existing case/actuator behind the new reduction case, and as such, you just use the existing "knob" for actuating the standard low/high/4x4. IMO all these are low effort/cost relative to the rest of it and not a big deal.

I like NWF because I believe it may be stronger, slightly more simple, and is shorter in length. I don't like that I'd have to swap input shafts on existing t-case. I don't like that I have to find a good donor case (this seems simple but if you find a manual J shift case you have less to do like converting an electric case to manual etc, but a J shift case is expensive because they are desirable). It requires a lot of work to build the case yourself.

I like the M/C because they've been doing this a while. I like that I can just get an auto case and replace my existing case with that and mount the already built TacoBox unit to that and the trans. I don't like the cost... but I'm not convinced that all said and done that the cost is a big differentiator between NFW and M/C though.

Anyway hope some of that helps... stream of consciousness post here.

I've been looking at the Eco crawler for the 4runner. pretty sure this is the route i plan to go.

 

[brettf]

I've been looking at the Eco crawler for the 4runner. pretty sure this is the route i plan to go.

Keep us posted how it goes?

 

[MarkEva]

So thanks for all the replies. After some research and phone calls my mechanic decided on a Trail Creeper, which goes between the transmission and the transfer case and has: no reduction, neutral and 2.88:1 reduction with a lever poked up through the stick shift boot and no electrical connections. I am starting to get a sense of how much money you guys spend building up your Cruisers. Maybe this will be the last thing.
Thanks again,
Mark

 

[brettf]

@MarkEva and @Notyourmomslx450 report back on how it goes?

 

[MarkEva]

My mechanic, Greg Mandile, installed the Trail Creeper Crawl Box. It was a big job, doesn't fit perfectly, he needed to extend 17 wires that went to the transfer case. It's noisy, shifts roughly, but I can't wait to drive it around on Thursday. He said he'd do followup on it too, so maybe that will help smooth it out.

 

[brettf]

Heck yeah - score one for the Trail Creeper. The parts are available! Let us know after you get some time into it. Assuming the noise isn't an issue and it holds up, I'm certain you'll love having the lower gearing available with the 3G tacoma.

Excited for you, I think it'll be great!

 

[DouglasVB]

How much did it end up costing in total?

Something like this is eventually in my future for my 3rd gen taco with the 6MT. I still miss my dual t-cases in my old 4runner with the 4.7:1 gear in one of the cases. That was such a great setup.

 

[brettf]

Here's a link to a built dual case from Marlin Crawler that will fit a 2nd gen Tacoma with manual trans. The price is good considering!
FB Marketplace Link

Not super relevant to your truck @MarkEva, or yours, @DouglasVB, but in case it helps anyone else.

I did look into this built dual case for my own 3g Tacoma, but it isn't a direct fit; you'd need a different trans adapter than this comes with. And I'm not sure if you could use the rear case as-is either for a 3g. The little nitpick details with the different permutations of trucks, cases, input shafts, make the process tricky.

I'm pretty far down the planning path for using the NWF ecoCrawler setup for a different truck. I'm hearing that the noise is significantly less than using a gear driven case. We'll see.

 

[DouglasVB]

Here's a link to a built dual case from Marlin Crawler that will fit a 2nd gen Tacoma with manual trans. The price is good considering!
FB Marketplace Link

Not super relevant to your truck @MarkEva, or yours, @DouglasVB, but in case it helps anyone else.

I did look into this built dual case for my own 3g Tacoma, but it isn't a direct fit; you'd need a different trans adapter than this comes with. And I'm not sure if you could use the rear case as-is either for a 3g. The little nitpick details with the different permutations of trucks, cases, input shafts, make the process tricky.

I'm pretty far down the planning path for using the NWF ecoCrawler setup for a different truck. I'm hearing that the noise is significantly less than using a gear driven case. We'll see.

What gear ratio is available with the ecoCrawler? Is it only the stock ratio?

In my old 4runner, I switched from the stock low range in both cases to the 4.7:1 gearing for one of the cases and that made a huge difference for me.

But yeah you're right about the noise of geared transfer cases

 

[coloryan]

What have you heard about heat dissipation in the ecoCrawler?

I've heard that's an issue with their Landcruiser Blackbox since it's a separate sealed unit with a limited amount of gear oil. Also, my understanding is the 1:1 still results in planet gear rotation, and therefore generates heat, since the ring gear is fixed to the housing. Installs I've seen require a separate oil cooler to keep the gears from cooking themselves during highway driving. I'm not sure how different the ecoCrawler is though...

 

[brettf]

What gear ratio is available with the ecoCrawler? Is it only the stock ratio?

In my old 4runner, I switched from the stock low range in both cases to the 4.7:1 gearing for one of the cases and that made a huge difference for me.

But yeah you're right about the noise of geared transfer cases

Yes - the stock ratio only - so you get two 2.73:1 cases (or whatever exact ratio is). I'd love to have the 4.7 but I hope the second 2.73 reduction will be good enough.

I bet that 4Runner was capable with that combo!