T Case Input Upgrade

[tnxjjeeper]

What kind of upgrades have you guys done for the Tacoma T Case input shaft? I'm affraid when I get my junk back together (R151F, 4.7 Crawl Box, Stock Tacoma T Case, 60/14 Bolt, 40" MTR's), the input shaft won't be up to the challenge. Does anyone make an upgraded shaft, or maybe cryo the stock ones? What works and what doesn't? I have a stock case I thought about carrying for a spare, but it would still be a pain to change on a trail when the splines are stuck in the adapter.

Chris

[TacomaJoe95]

All you can do is have it cryoed. I broke one a few years ago. Had it cryoed and it has not been a problem since. Just be careful of the case it self. They break easy. I have broke 4 in three years.

[Trailer Guy]

Originally Posted by TacomaJoe95

All you can do is have it cryoed. I broke one a few years ago. Had it cryoed and it has not been a problem since. Just be careful of the case it self. They break easy. I have broke 4 in three years.

x2, Cryo the shaft, but then the casing itself will be the weak link.

Oh, and even if they do break, you can weld them back together to get off the trail. I wasn't there, but I'm guessing the guy that posted above me could tell you how it is done.

***edit***
Just for fun, TacoJoe's statement is useless without fawkin pics.

[Dickfoster]

I broke one early on, froze the replacement and haven't had a problem with it since. Actually Marlin did mumble something about a binding issue that could have contributed to the first one busting. I have his #3 taco box.

[NorcalVP]

Originally Posted by Dickfoster

I broke one early on, froze the replacement and haven't had a problem with it since. Actually Marlin did mumble something about a binding issue that could have contributed to the first one busting. I have his #3 taco box.

So I hear that you are a member of the band on TTORA...

[Dickfoster]

Yeah, I told them to take a hike. I just got tired of dealing with all the mall running asshats and the non contributing or participating bullshit mods who have nothing better to do than sit on their fat ass and tell others how the world should be. So yeah, I guess I said fuckem then they said you're banned LOL. It's like firing someone who's already quit and walked out the door. Maybe banning folks is supposed to make your penis grow or some shit. God knows, some of em are sure short on balls.

[TacoDell]

Too bad you can't remove all the information you shared with those folk over the years... screw 'em... they don't deserve the know...

I guess I'll have to come over here if'n I feel the need to get me a good ass chewin'... LOL

odd... to see you with only a 28 post count here...

[highplainsdrifter]

Originally Posted by Dickfoster

Yeah, I told them to take a hike. I just got tired of dealing with all the mall running asshats and the non contributing or participating bullshit mods who have nothing better to do than sit on their fat ass and tell others how the world should be. So yeah, I guess I said fuckem then they said you're banned LOL. It's like firing someone who's already quit and walked out the door. Maybe banning folks is supposed to make your penis grow or some shit. God knows, some of em are sure short on balls.

TTORA is totally screwed up now. The asshat newbs run the show, it has become customtacos re-vamped. Fawk that site and all its web-wheeling wanna be's.

[Sisyphus]

Originally Posted by NorcalVP

So I hear that you are a member of the band on TTORA...

Didn't you hear? He plays the skin flute

[=ACID RAIN=]

Originally Posted by Dickfoster

Yeah, I told them to take a hike. I just got tired of dealing with all the mall running asshats and the non contributing or participating bullshit mods who have nothing better to do than sit on their fat ass and tell others how the world should be. So yeah, I guess I said fuckem then they said you're banned LOL. It's like firing someone who's already quit and walked out the door. Maybe banning folks is supposed to make your penis grow or some shit. God knows, some of em are sure short on balls.

After having a worthless discussion with shannonigans, I took off as well. Fuck it - fuck em.

[highplainsdrifter]

Originally Posted by =ACID RAIN=

After having a worthless discussion with shannonigans, I took off as well. Fuck it - fuck em.

Exactly, fuck them and their gay assed web wheeling site. I will still go on there to sell stuff but this is where it ends for me. Noone on there knows shit about shit anymore, they just think they do and spread alot of misinformation around the web... what a joke!

[Brian Ellinger]

Our taco has never busted one. Probably since we had a spare, go figure.

3.4 5spd, 4,17 to taco case, 5.43's in 9's and 42's, 4700 lbs. Broken several rear u-joints. Im guessing the ones who have broken are in supercharged rigs. Possibly rigs with high ring/pinion (4.10's etc)

[tnxjjeeper]

I'm thinking I may just save a little more, bite the bullet, and put an Atlas behind my crawl box. Yeah, it's expensive, but this project is about doing it right the first time...

[snowchucker]

just get it cryo'd. I carry a spare and heard about one snapping last weekend on the TTORA rubicon run (behind a Tundra v8).
Marlin even drove up and wheeled in to fix it personally.... thats some awsome customer service.

[=ACID RAIN=]

Originally Posted by snowchucker

Marlin even drove up and wheeled in to fix it personally.... thats some awsome customer service.

Wish I lived closer to that dude...or perhaps he lived closer to me

[Inchworm]

Hey Guys,

The reason that the input on the tacoma case is a concern is because of the 4.7 crawl box in front of it. When you put the gearset in the rear case instead of the front one you have less than half of the torque load on the 2nd input shaft. This is a major advantage of running a Lefty tcase in your Taco, Tundra, 4Runner, or FJ Cruiser. Take a look at the torque load comparison in the diagram below...The 100 lbft (just a round number for simplicity) of the engine is multiplied by the gear ratios. As you pass through each gearbox the torque is multiplied. You'll see that the final numbers are pretty close to the same, the difference is the torque load on the input of the rear case. This means you are less than half as likely to break it!

[BigMike]

Originally Posted by snowchucker

just get it cryo'd. I carry a spare and heard about one snapping last weekend on the TTORA rubicon run (behind a Tundra v8).
Marlin even drove up and wheeled in to fix it personally.... thats some awsome customer service.

Yup, that would be from Joe

Check out the whole story here:
http://board.marlincrawler.com/index.php?topic=35271.0

[BigMike]

Originally Posted by Inchworm

When you put the gearset in the rear case instead of the front one you have less than half of the torque load on the 2nd input shaft.

Jim,

I am still researching this, but you may not be correct on this.

I spoke to my machine design instructor last semester, and he said this theory is incorrect due to the equation N1*T1=N2*T2.

There is an incomplete discussion about this between me and an engineer on our forum at this link below:
http://board.marlincrawler.com/index.php?topic=28881.0

Please read that thread to its entirety and let me know what you think. It is one of the very few things that I've not been able to explain myself well enough, and thusly I have left my pending response out for the readers own interpretation.

[BigMike]

Originally Posted by Inchworm

This is a major advantage of running a Lefty tcase in your Taco, Tundra, 4Runner, or FJ Cruiser.

I do agree on this point, especially if you consider using a Total-Spline input gear in the Lefty. The Total-Spline is however only available exclusively through Marlin and Marlin alone. He has 2.28:1 and 4.70:1 Total-Spline ratios available.

[Brian Ellinger]

Interesting read Mike.

I would agree the input on the second case is under less stress with both cases in low. Simple because the drivetrain is typically under constant load. Think 200hp clutch dump vs. 200 hp at highway speed. One is constant load with the drive train turning, one is shock load. Its odd and typically useless to drop a clutch in low/low. However it can be very handy in stock low (front case low, rear case 4wd) Right now Im thinking of snow runs in CO. Also, needing tire speed, loose rocky hill, justifies 4wd stock low. That would put more stress on the input of the second case IF you are in low in the front case, and high in the rear case. The input of the second case would not see any increase in strain, if you were simply in 4wd low in the rear case, and high in the front case.

In your thread you touch on stock 21 spline inputs breaking. I know of one busted with 2 stock gearsets, in the rear case, rare but happens. The owner also spent a LOT of wheeling time in first case low, second case 2/4. Then shifted the rear case to low for harder obstacles. 4cyl carbed truck, running 40" boggers.

I do not know anyone who has popped an input 21 or 23 spline of Marlin gearsets, hence why I have always been comfortable running 21 spline, with the rear case having the gearset.

The Taco setup throws the planetary setup into the equation, so you have to run the gearset in front. I think the input concern is valid, but still a rare occurance. I would be interested to see if there is a pattern with typically older or newer Tacos, or motor/tranny setups. Perhaps there is a flaw in one particaular year range, or motor/tranny setup?

[tnxjjeeper]

I've decided to just leave the Tacoma case in the rear. I ordered a clockable adapter from Inchworm today to get a nice, flat underside. I also ordered a crossmember center section from Front Range today to help with the support. I guess I'll just have to carry my spare case with me...

[BigMike]

Originally Posted by Brian Ellinger

Interesting read Mike.

Thanks buddy. It was almost refreshing reading it again; it feels like I wrote it a year ago. I do remember I was glad that not many people had seen it at the time but now I am using it on the worlds largest forum to explain a point.

I don't think I would reply to that thread, not right now, but I think my argument holds only because in that situation, we are comparing 47:1 vs 108:1. But in Jim's (Inchworm) analogy above, his ratios are more comparative which is what made me think twice when I was reading it.

I think with deeper thought and even real world testing I would have to agree with RRMike. The change in resistance he illustrated certainly is a convincing point.

I think I remember discussing this regarding Marlin's truck vs. his rear axle shaft here on pirates. I think I got hosed on that one. How in the world can Marlin's truck (formerly 1,047:1, now 1,372:1) not have ever broken a rear Toyota axle shaft that Bobby has tested to fail at only 6,500 ft-lbs? The discussion was of course over the fact of his Crawl ratio allowing well in excess of 130,000 ft-lbs of torque, logically in a purely theoretical setting. Theoretical vs. Applied torque....... It must have been three or four years ago. I think I was arguing over how much torque was really being produced in the real world, not theoretical. Remember his engine doesn't develop that much torque at 600 RPM, yet it IS impossible to stall it out. Ohh the good ol days

[BigMike]

Originally Posted by tnxjjeeper

I've decided to just leave the Tacoma case in the rear. I ordered a clockable adapter from Inchworm today to get a nice, flat underside. I also ordered a crossmember center section from Front Range today to help with the support. I guess I'll just have to carry my spare case with me...

Good choice Having dual cases will make a night and day difference, and Brian's crossmember is awesome! I'm running on in my rig as well

[tnxjjeeper]

Originally Posted by BigMike

Good choice Having dual cases will make a night and day difference, and Brian's crossmember is awesome! I'm running on in my rig as well

I was running a set with a stock gear, but while I'm still down I went ahead and put a 4.7 gear in the crawl box and I'm going to clock the rear case.

[BigMike]

Originally Posted by tnxjjeeper

I was running a set with a stock gear, but while I'm still down I went ahead and put a 4.7 gear in the crawl box and I'm going to clock the rear case.

Cool. Inchworm's clocked case, like Marlin's, really gets the d/line up and out of the rocks. Upgrading to an "Ultimate" will really blow your mind! You thought duals were great when you first installed it, just wait!