Topic: New to crawling, in search of tips and tricks.

[Xull]

Hello, I'm wondering if anyone would bother answering some questions I have regarding gearing and transfer cases.

I'm running a 1982 singlecab Toyota Hilux with a chevvy v8 engine swap, Th350 automatic transmission and a stock 82 hilux(toyota truck) transfer case with stock axles. Currently enough lift to run my super swamper tsl 38" tires.

I've come to realise I need to do something with the gearing and have been browsing the marlin crawler shop up and down to get none the wiser.

So my first question is, does a duel case kit exist that bolts on to my current setup ?

Second, should I get a 4.70:1 kit for my stock transfer case ?
And last but not least, I'm guessing I should have upgraded my ring and pinion in the differential, but I'm unsure of what gear ratio. With those big tires should I just get the 5.29:1 kit ?

Thanks in advanced and greetings from Norway.




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[OVRAROK]

 
 

First ?..yes..if you have your original t case in truck..then adding duals is a bolt in..you'll need to adjust DLs add hole in tunnel. And get a dual crossmember..

[Xull [OP]]

 

First ?..yes..if you have your original t case in truck..then adding duals is a bolt in..you'll need to adjust DLs add hole in tunnel. And get a dual crossmember..

Thanks

Original transfer yes, but is it the Dual Case Kit MC08 I need ? I'm unsure because of the Chevvy TH350 automatic transmission.

Should I also aim to swap out my original tranny gears with 4.70:1 gears ? Or would that be pointless?

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[OVRAROK]

Thanks

Original transfer yes, but is it the Dual Case Kit MC08 I need ? I'm unsure because of the Chevvy TH350 automatic transmission.

Should I also aim to swap out my original tranny gears with 4.70:1 gears ? Or would that be pointless?

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If you truck is driving...you must have an adapter from t350 to your original tcase..so dual cases will bolt up..the 4.70 gears that marlin sells are for the transfercase..NOT the tranny..if your planning on running duals..you may as well break the bank and order the Dual ultimate 2 28/4.7.. you cant go wrong...  Also with tires larger then 35s I would recommend 5:29 gear ratio for your diffs...

[Xull [OP]]

If you truck is driving...you must have an adapter from t350 to your original tcase..so dual cases will bolt up..the 4.70 gears that marlin sells are for the transfercase..NOT the tranny..if your planning on running duals..you may as well break the bank and order the Dual ultimate 2 28/4.7.. you cant go wrong...  Also with tires larger then 35s I would recommend 5:29 gear ratio for your diffs...

Ah okay. My terms got a bit mixed up there. It's kinda confusing. I ment to ask if the 4:70 gears is for the stock transfer case or if it's something you  fit to the crawler box.

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[OVRAROK]

In your case...with your year..ideally you would have 21 spline crawl box with 4.70 geared rear transfercase..the case will need to be clearenced for the larger 4.70 gears..there are plenty of vids explaining this..

[Xull [OP]]

In the text for the transfer case 4.70:1 gears it states
"Application: Any 1979-95 gear drive 4-cylinder transfer case. Please see our line of conversion adapter plates for V6 and V8 gear drive and chain drive applications which are required to run our 4.70:1 gears in automatic applications."

The part about automatic applications does it not matter seeing as the transfercase is from a manual driven car ?

Thanks for the help so far. Starting to make sense to me now

Just trying to get it right the first time seeing as shipping and import fees are ridiculous.

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[toyodaaddict]

In your case...with your year..ideally you would have 21 spline crawl box with 4.70 geared rear transfercase..the case will need to be clearenced for the larger 4.70 gears..there are plenty of vids explaining this..

To make this more confusing and get into spline count, op can use a 21 spline crawl box, 23 spline dual case adapter and 23 spline 4.70 gear set, right?  Its my understanding this is the strongest way to go and what I was planning to do when I get 4.70's.

[Xull [OP]]

Hmmm okey ive done some more reasearch now.

So I have a th350 automatic transmission with a 27-21 spline adapter that goes to my transfer.

I have a spare transfercase with a 21 spline aswell.

Does that mean I can buy a 23 spline adapter kit, install 4.70 gears with 23 spline for my current transfercase and those 3 will bolt on ? (I understand there is some modification to the transfercase with 4.7) or do I need a new spline input gear aswell that is 23 spline ?
https://www.marlincrawler.com/transfer-case/gears/hilux-gear-drive/total-spline-input-gear

 but other than that it's just to add support and modify the drive shafts ?

[redneckcustoms13]

I have a 350/t350 in my toyota mud truck. With stock 410 gear and stock case it does just fine. In your case since you are wanting to crawl. Keep this all simple and just put a 4.7 gear set in your case and othwrwise leave it as is.

[Xull [OP]]

I have a 350/t350 in my toyota mud truck. With stock 410 gear and stock case it does just fine. In your case since you are wanting to crawl. Keep this all simple and just put a 4.7 gear set in your case and othwrwise leave it as is.

I think my Th350 automatic is only a 2.52:1 if im not mistaken. Even with a 4.7 setup in my transfer case my ratio would only be what around 57:1 ? With the 39" tires it barely moves

[Xull [OP]]

Anyone that could tell me if I can run 21 spline into my crawler box and 23 spline out into the dual adapter box and 23 spline transfercase ?

My transmission has a adapter plate with a 21 spline setup. Or do I need to swap out the adapter plate with a 23 spline setup ?

I imagine 21 spline all the way with 2.28 and 4.70 would wreck something.

[redneckcustoms13]

Unless you are just determined to waste over $2000 us dollars I am telling you, I have the exact same set up except running 44" boggers instead of 39s. The ridiculous low gearing all these guys ; myself included, go for is on manual shift trucks. Comparing an auto with 4.7 tcase to a w56 with a 4.7 case is like comparing a boat to an atv. The auto has a torque converter that allows the engine to come up in rpm before the transmission will pull. Manual obviously does not, release clutch you are locked in and it goes. If you put a dual ultimate set up 2.28 front case, 4.7 rear case you will be turning the guts out of the engine. It will constantly be shifting out to 3rd gear unless you lock it down to 1st. Even in that case, locked in 1st at 3000 rpm your tires would still only be turning 2.98 mph.

Save your money. Build a case with 4.7s. Put it in. If for some reason you are still not satisfied then blow the money for a doubler adapter and new driveshafts. Personally I believe you would be fine with just a 4.7.

On the 23 or 21 spline debate. 23 spline is stronger. Always try to get 23 spline.

[Xull [OP]]

Unless you are just determined to waste over $2000 us dollars I am telling you, I have the exact same set up except running 44" boggers instead of 39s. The ridiculous low gearing all these guys ; myself included, go for is on manual shift trucks. Comparing an auto with 4.7 tcase to a w56 with a 4.7 case is like comparing a boat to an atv. The auto has a torque converter that allows the engine to come up in rpm before the transmission will pull. Manual obviously does not, release clutch you are locked in and it goes. If you put a dual ultimate set up 2.28 front case, 4.7 rear case you will be turning the guts out of the engine. It will constantly be shifting out to 3rd gear unless you lock it down to 1st. Even in that case, locked in 1st at 3000 rpm your tires would still only be turning 2.98 mph.

Save your money. Build a case with 4.7s. Put it in. If for some reason you are still not satisfied then blow the money for a doubler adapter and new driveshafts. Personally I believe you would be fine with just a 4.7.

On the 23 or 21 spline debate. 23 spline is stronger. Always try to get 23 spline.

So you are telling me that if I only swap out for a 4.7 in the transfercase my car will be able to move on it's own when in gear ? As of now I have to give it throttle the the thing to move and it's at the point where it's really just digging inn when I gently try to throttle it up.

I Have a Th700R4 tranny that came with the car when I Bought it. Would that be a better option for crawling ?

Maybe get the 4.7s and swap out the 350 for the 700 and see how that goes ?

Do you have any suggestions on what else should be upgraded before I try to go duals ? 30spline chromoly axle kit ? Already shattered a cv joint.

[redneckcustoms13]

The 700r4 has a lower 1st gear and an overdrive. It's a much better transmission for this. However they aren't nearly as reliable as a t350. If you have the 700r4 built to hold the power sure it could be great. But... this will open a new can of worms 700r4 is longer than a t350 unless you have a long shaft t350.

The previous owner probably built this is a mud truck. You say you have to give it throttle to move even in low range. More than likely they built it with a higher stall converter. That would allow them to get it revved on up before it starts pulling. What rpm does it reach before it starts to actually move?

[Xull [OP]]

Havent been able to see that yet as its only stock dash with speedometer. Car is built for mud, forest offroading. That and snow is what we mostly have in Norway. But I've always wanted a car with crawler speed and that's what I'm hoping to be able to build

[redneckcustoms13]

Get yourself a cheap tachometer from the auto parts house. I'd bet it has a real loose converter meant more for racing than slow speed.

[Xull [OP]]

Get yourself a cheap tachometer from the auto parts house. I'd bet it has a real loose converter meant more for racing than slow speed.

Did some research and took your advice. Got myself a 4.70

Going to fix the torque converter or swap it out and maybe do a tranny swap to the 700 in the future. It's some rather expensive rebuild of parts here in Norway I've come to realize.

[redneckcustoms13]

Did you order a 4.7 set with 21 or 23 spline? If you got 23 did you get a new coupling adapter from whoever made your current adapter?

[Xull [OP]]

Did you order a 4.7 set with 21 or 23 spline? If you got 23 did you get a new coupling adapter from whoever made your current adapter?

Got the 21. Hoping it will survive the engine. Less hassle with changing stuff up for the moment.

When they say you want 23 spline if you are doing duals, can you 21 into the crawler box and 23 in the transfer case ? If so how do they do that ?

[redneckcustoms13]

How this works is essentially two separate cases. The crawl box is the front case. All it will have is high, neutral, and low. The rear is the normal transfer case that you are about to put 4.7 gears in.

As for the 21 spline lasting, I have never broken one. My mud truck only plays in mud. I have a rig with duals and a manual trans for crawling. I wouldnt attempt to do a 21 in a dual set up. But I ran single 4.7 21 spline set up on 39.5 iroks for a few years with no issues.

[Xull [OP]]

How this works is essentially two separate cases. The crawl box is the front case. All it will have is high, neutral, and low. The rear is the normal transfer case that you are about to put 4.7 gears in.

As for the 21 spline lasting, I have never broken one. My mud truck only plays in mud. I have a rig with duals and a manual trans for crawling. I wouldnt attempt to do a 21 in a dual set up. But I ran single 4.7 21 spline set up on 39.5 iroks for a few years with no issues.

But you have to run 23 all the way right ? You can't go 21 from tranny to first box then 23 to the transfercase ?

[helipilot77]

you can mix the input and output spline count in each transfer case. theoretically you could have:
21 spline into 1st T-case with output of 23 spline into 2nd T-case with input of 23 spline
or
23 spline into 1st T-case with output of 21 spline into 2nd T-case with input of 21 spline (weak due to multiplication of torque from first T-case)
or
all 21 spline
or
all 23 spline
as long as the output matches the receiving input it will work.
In the diagram you can see that the input shaft and output shaft while they are in alignment with each other, there is a bearing separating them so they can turn at different speeds. This is what makes low range possible. They can be locked together at the clutch sleeve in order to engage high range (1:1). When low range is engaged the power flows through the input shaft, through the gears down to a counter shaft and then through another set of gears back up to the output shaft. Because they are separated you can change each individual component, be it a gear set or a shaft with different spline count. In the marlin duel transfer case design the part that makes it so special is the custom output shaft that has been made shorter with female splines on the rear portion of it in order to mate to a input shaft of a separate reduction gear case. In this way an unlimited number of reduction cases could be stacked. Hopefully this helps to clear up some of the confusion.