"diesel" t-case gears

Any update on the feasibility of these gears?
Since it seems as if a 1:1 will severely limit the low range ratios possible, I really think something like a 1.15:1 would be a good compromise. The 16v Sidekick 2wd trans has the same 5th ratio of .795:1 as the early Samurai trans, and would become the go-to for Samurai diesel swaps if one could identify via parts dismantlers if the donor vehicle had the 16v vs the 8v 1.6L...
Heavier flywheel is the biggest gain, as it dampens the diesel vibrations significantly better than the featherweight tiny little Samurai flywheel.  Larger clutch is another bonus, and larger/stronger internals and more fluid capacity and metal mass for better heat dissipation is the other great benefit to this 2wd 16v transmission upgrade.
I have one of these trannies and would love it if I could get a set if 1:1 or 1.15:1 t-case gears with a 3:1 low range at minimum. That's a far better spread than the stock Samurai with it's 1.41:1 high range.

With a 1:1 high range, or even the approximate 1.15:1 that I'd propose, even the 8v Sidekick 2wd trans would be a great choice.
A smooth idling (freshly valanced injectors & new nozzles) 1.6TD would do alright with a stock Samurai trans, but more power out of a very hopped up TD or a mildly modified TDI, & the little Samurai trans is not a good choice whatsoever for longevity.
 
Chuck78 said:
Any update on the feasibility of these gears?
Since it seems as if a 1:1 will severely limit the low range ratios possible, I really think something like a 1.15:1 would be a good compromise. The 16v Sidekick 2wd trans has the same 5th ratio of .795:1 as the early Samurai trans, and would become the go-to for Samurai diesel swaps if one could identify via parts dismantlers if the donor vehicle had the 16v vs the 8v 1.6L...
Heavier flywheel is the biggest gain, as it dampens the diesel vibrations significantly better than the featherweight tiny little Samurai flywheel.  Larger clutch is another bonus, and larger/stronger internals and more fluid capacity and metal mass for better heat dissipation is the other great benefit to this 2wd 16v transmission upgrade.
I have one of these trannies and would love it if I could get a set if 1:1 or 1.15:1 t-case gears with a 3:1 low range at minimum. That's a far better spread than the stock Samurai with it's 1.41:1 high range.
Click to expand...


I have not heard anything, but, this is another reason I?m tempted to try an auto. Supposedly crawl ratio is approximately doubled what your final calculated ratio would be.

The AW72 I have has a 2.83:1 1st, and a .73:1 4th gear, with a lockout. So my CR would theoretically be about 29:1
 
Any updates on this? Brendan Theole on the Suzuki Diesel FB group page last said a month or 2 ago that Sumo were in the design stage, and that a 1.0:1 high range & 4:1 low range is what would be do-able.

https://m.facebook.com/groups/660874577354867/permalink/3253836704725295/


 
Chuck78 date=1609688035 said:
Any updates on this? Brendan Theole on the Suzuki Diesel FB group page last said a month or 2 ago that Sumo were in the design stage, and that a 1.0:1 high range & 4:1 low range is what would be do-able.

https://m.facebook.com/groups/660874577354867/permalink/3253836704725295/
Click to expand...
 
 

I emailed Sumo Gear to find out.... Here is the reply:

Hi Derrick,

Thank you for your interest in Sumo Gear.

Yes you are correct we were looking into that possibility.  However, after reviewing the Samurai transfer case in detail, unfortunately, it is simply not possible to create a hi-range of 1.0:1 using the existing transfer case housing.  In order to achieve that ratio, or anything close to that, the input and hi-speed gear need to be the same or near the same tooth count which would also mean their diameters would be equal.  In the chart below, under stock highlighted in yellow, you can see the tooth count of each gear (44 teeth on the input and 62 on the hi-speed) and attached you can see their physical size difference.  The main issue is, when increasing the input gears diameter it becomes too large to fit into the stock case.  There are other technical obstacles, like centerline distances between the input ? idler ? output that also make it impossible in the stock case?




I wish I had better news but unfortunately without a new case there really isn?t an option.

Best Regards,
Greg

:\\\'( :\\\'( :\\\'(

Here is a screenshot of the email. he has a nice table in there that didn't work with the forum....
bad news.webp

 
Well, that's disappointing, but I'm glad the possibility was evaluated so we have a real answer.

I hope I can sort out my Jimny electric transfer case. With the TG gear kit it's 1.17 high and 3.74 low, which is an improvement in both directions. Add axle gearing and you can trade some of the high range gains for much better low range. With tracker 5.125 thirds I'd get a 70:1 crawl ratio and ~3500rpm at 70mph on 30s.

The trouble with that swap is that it's electrically shifted (not the worst, it's just a 12V motor and some limit switches) and there's a vehicle speed sensor instead of a speedo cable drive, which I think is the bigger problem. I halfway designed a controller for it that could drive a motor to drive the speedo, and I can't decide if it's best to continue on that path or to replace the speedometer mechanism entirely. Driving the existing speedometer means I have to read the VSS sensor and then drive a motor at the right speed somehow, with an appropriate coupler to the speedometer. Replacing the speedometer with a stepper-driven needle and an lcd odometer is a lot more straightforward in terms of electronics design, but the mechanical fitment is very tricky due to the way the gauge cluster is constructed. I think I'd have to 3D print some parts to fasten it to the back of the gauge cluster (like stock) and raise the new assembly up to the level of the other gauges.
 
I made a thread about it here. There are kits for swapping in the other direction, to put a Samurai case into a later Jimny. It's desirable to do because the stock Samurai transfer case is better geared than the stock Jimny case, and also some people have problems with the chain in the Jimny case slipping. I hope that's because they're upgrading a worn out transfer case, not because it's fundamentally unsuited for the task.  :-X

It is a divorced case like the one in the Samurai, and it mounts similarly, but not similarly enough that you can swap over the mounting brackets from one case to the other. I think the flanges are interchangeable.
 
k1n3k date=1609895467 said:
I emailed Sumo Gear to find out.... Here is the reply:

Hi Derrick,

Thank you for your interest in Sumo Gear.

Yes you are correct we were looking into that possibility.  However, after reviewing the Samurai transfer case in detail, unfortunately, it is simply not possible to create a hi-range of 1.0:1 using the existing transfer case housing.  In order to achieve that ratio, or anything close to that, the input and hi-speed gear need to be the same or near the same tooth count which would also mean their diameters would be equal.  In the chart below, under stock highlighted in yellow, you can see the tooth count of each gear (44 teeth on the input and 62 on the hi-speed) and attached you can see their physical size difference.  The main issue is, when increasing the input gears diameter it becomes too large to fit into the stock case.  There are other technical obstacles, like centerline distances between the input ? idler ? output that also make it impossible in the stock case?




I wish I had better news but unfortunately without a new case there really isn?t an option.

Best Regards,
Greg

:\\\'( :\\\'( :\\\'(

Here is a screenshot of the email. he has a nice table in there that didn't work with the forum....
View attachment 247945
Click to expand...

I wonder if it'd be possible then to make minor change to the input gear and counter gear sizes, & high gear, from 44, ##, & 62, etc down proportionately to 48 (+4), ##, & 58 (-4), etc if the diameters would then work out for proper gear mesh?
That would work out to be a 1.21:1 high range, which would still be very beneficial to a Samurai diesel swap when retaining the stock 3.73 differential gearing.
The 2 questions remaining then would be - will a +4T input gear diameter fit? And, if so, what would the deepest low range gearing possibilities be with the input gear size reduced?

 
By the way, I just did some quick calculations on Grimm-Jeeper, & even at 1.21:1 high range, if that were a possibility, we could drop the highway cruising engine speed by 457 RPM, that is QUITE SIGNIFICANT still...
And WELL WORTH asking Sumo what it would take to get somewhere near that ratio in high range, and what the corresponding low range could potentially be at its lowest...

Screenshot_20210106153013.webp

This chart shows cruising speeds @ 55, 65, & 70mph on a pre-1988.5 transmission & 30.7" ("31-inch") tires... larger diameter tires also help with the gearing slightly, 32 is pretty ideal for a samurai for a mix of on and off road use without going too crazy and needing major sheet metal clearancing.
255/75R17, 245/75R17, 235/75R17, 265/75R16, 245/75R16, 31x10.5R15, etc...
Or 33x10.5R15 or 255/85R16 TrXus MT Radials if one was wanting fairly big tires...
255/75R17 on a 17x7 wheel is probably my favorite all-around size and a common Jeep upgrade size, I believe OEM on some more recent model Jeeps also. 32.2"x10.0", very nice... The Yokohama Geolandar G003 in that size actually measures 33 in in real life, pretty impressive! And the Goodyear Wrangler DuraTrac is actually pretty darn lightweight for being a 32x10, right at around 40 lbs. The Geolandar G003 M/T is 48 lbs, and despite it's aggressive tread, is engineered very well and is pretty darn quiet for how aggressive it looks
 
Could anyone that has had contact with Sumo inquire with them about a compromise for a gear ratio of around 1.2:1 or 1.23:1 high range in a samurai transfer case?
 
Also, I had read about another member on here looking into these diesel gears years ago, and he found that OEM diesel Samurais did have their own unique gearing, but he said they were difficult to come by.
Just by chance when looking up Samurai transfer case gear parts fiche diagrams on megazip.net, I happened to see two Samurai sub models called the SJ419D & SJ419TD...

Screenshot_20210108195116.webp

The SJ419D came with a normally aspirated indirect injection Renault diesel engine.
The SJ419TD came with a Peugeot / Citro?n 1.9 L turbo diesel indirect injection engine...
Standard is 41/11 differential gears, but these models came with 41/12! That's 3.42! vs 3.73 stock...

Screenshot_20210108194944.webp

Those certainly would solve the Samurai diesel problem we have with swapping Volkswagen diesels in. But sadly, they are showing up as discontinued.

Screenshot_20210108230156.webp

Screenshot_20210108230309.webp



41/12 diff gears would definitely solve the Samurai diesel problem with the transfer case gearing, and you could still run deeper low range gears (typically 10% additional high range underdrive) and 31", 32", or 33" tires...

However, having diesel-specific differential gears made, installing them &  and setting them up properly, would not be nearly as preferred as transfer case gears that could do similar and also give a deeper low range...IF we could even get a 1.21:1 or 1.25:1 high range + any decent low range out of a Samurai transfer case...

Two differentials worth would likely cost a bit more than one set of transfer case gears, and many Samurai owners will also want deeper low range gearing than stock as well... But this is a guaranteed way to be able to retain the Samurai transfer case at least... And the 41T ring gears are stock offerings, however may need to be slightly thinner to mate with a 1T larger 12T pinion gear???? At any rate, we know these would fit...

Unfortunately, they show as discontinued, and I believe these 1.9L diesels were only offered in the Samurais made by Santana for the 1999 and 2000 model years for Spanish and African markets? The Suzuki Santana parts catalog manual I have downloaded says its Rev.3 2000-2012, but does not list individual years for the diesel options.

 
I think a Sidekick/Tracker/X-90 rear axle housing may be a decent alternative to run with a Sidekick/X-90/Tracker 4wd transmission & 1:1 high range transfer case...BUT... the Samurai front axle is a lot narrower, and requires 1.5" or 2" wheel spacers to get close enough to match the 'Kick rear.
I'd probably look into narrowing a Sidekick rear significantly and adding full floater flange adapters to run front axle hubs etc and get it back down to near the Samurai front width, & run drive flanges with double splined axles, no bolt-on flange, just an axle with splines on both ends, drive flanges instead of freewheeling lockout hubs.
 This takes some fab skills & very precise fixturing & alignment when welding to narrow the housing, but you don't have to do much of anything up front and you get a far stronger rear diff in the process.
Toyota axles are not much wider than the Sidekick/Tracker stuff either, and bigger axles than the Samurai, but then you're swapping both ends. 
Wheel spacers up front definitely are easier! Or ft & rr Yota axles...
 
Chuck78 date=1610219327 said:
Toyota axles are not much wider than the Sidekick/Tracker stuff either, and bigger axles than the Samurai, but then you're swapping both ends.
Wheel spacers up front definitely are easier! Or ft & rr Yota axles...
Click to expand...
 
Solid axle yota rear is 55", Sidekick is 57", ifs yota rear is 58".
 
Chuck78 date=1609961130 said:
I wonder if it'd be possible then to make minor change to the input gear and counter gear sizes, & high gear, from 44, ##, & 62, etc down proportionately to 48 (+4), ##, & 58 (-4), etc if the diameters would then work out for proper gear mesh?
That would work out to be a 1.21:1 high range, which would still be very beneficial to a Samurai diesel swap when retaining the stock 3.73 differential gearing.
The 2 questions remaining then would be - will a +4T input gear diameter fit? And, if so, what would the deepest low range gearing possibilities be with the input gear size reduced?
Click to expand...
 
 I actually sat down and tried to cad this out in solidworks, its not possible. for the high range, the input, counter shaft and output gear are all in mesh. Mind you, the center to center relation between the gears is fixed, so if you increase the input gear diameter, and decrease the countershaft gear diameter, you need to increase the output gear diameter. when you calculate the tooth count that maintains the spacing requirements, its pretty dismal. by bumping the input one tooth to 45, the countershaft went down one tooth to 40, and the output went up by one tooth to 63. bigger changes to the input are just countered by the output growing as well. the spacing worked out okay, but the gearing gain was going from the factory 1.409 to 1.400, and going up in the input another tooth resulted in another tooth increase on the output as well. this yielded 1.391:1 not much. BUT, there can be an increase in low range reduction without affecting high range. you could get a 3.066:1 ratio in low range without affecting the high range.



I did however figure out ONE way to tweak things. if you were to add a 3rd gear to the counter shaft by bolting it on to the side of the large gear on the counter shaft, then have the input mesh with that gear instead, you then have a TON of flexibility of gear ranges. i bet a near 1:1 high AND a 5:1 low are possible. it would also more evenly distribute some of the input shaft load more evenly on the center and outer case halves, strengthening the whole assembly. the high/low shift fork may have to be modified or replaced for gear clearance, but i dont believe it will interfere with the selector ring at all. Tooling for the extra gears might be the main issue though. 

Anyway, with that bombshell, i'm off to bed. good night!
 
Years ago.......one of the zuk enthusiast / builder [ forget who ] came up with, and sold a doubler. It was installed between the trans and and the TC input, and took the place of the intermediate shaft.
There was a problem with heat that was produced in it and me thinks that is what led to it's limited production and thus demise after this problem became apparent.

Thinking......a smart guy could design a doubler and use an oil cooler to cool it, even if it required a mechanical oil pump of sorts, or an electric oil pump of sorts.
 
that was the rock block. its problem was it was only useable at low speeds because there was no way to phase the input and output  u-joints, which would induce a wicked driveline vibe. 
 
k1n3k - so you just called it a night after figuring roughly a 1.39:1 high range and 3.07:1 low? Or did you determine that this was all that was possible with the Samurai case in the way of reducing the high range reduction?
Even a 1.27:1 high range would be worth pursuing if a similar / desirable low range were still possible...

Anyone else look into a 41/12 ring & pinion such as what came in the Suzuki Santana SJ419TD Samurai in Spain, Portugal, Brazil, etc and parts of Africa?
They're NLA from Suzuki it seems, but thats a 3.42 diff gear and yields awesome Samurai diesel highway RPMs.
Standard is 3.73, 41/11.

RevolutionGear.com sells Samurai diff gears for $188.09/set, I wonder how many 41/12 3.42 gearsets they'd need to make to do a production run?
I'd still say the transfer case gears would be the better route IF a 1.27:1 high range and desirable low range were possible... As many would be changing the t-case gears anyways for deeper low range
 
Chuck78 date=1611258707 said:
k1n3k - so you just called it a night after figuring roughly a 1.39:1 high range and 3.07:1 low? Or did you determine that this was all that was possible with the Samurai case in the way of reducing the high range reduction?
Click to expand...
 
 you can go more, but not a lot more. its because of the relation of the 3 gears. every time you add a tooth to the input, you have to add one or two to the output to keep the spacing correct. every tooth added to the input decreases the ratio .009 because of the 1 tooth increase on the output. hence why adding a separate gear on the counter shaft for the input is desirable. then you don't have the same relation between the input, counter and output gears on the high range.
 

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