Have been working on getting the correct final drive ratio. We decided to put in a NV 271/273 to get there. It is technically a 273 but we made it manual shift. Any ways will have better pics of the install later, but here it is. There is a little welding and drilling required. Had to make a new crossmember.







Got that all done and had a chance to pull today. We changed a 4200 spring. Was going real good until the 30 spline outer gave up. I don't know what the guy on the tractor was doing He pulled up right be for the flag dropped.





Guess we are going to do the 35 outer's sooner than I had planned.

 

That sucks, sorry.

 

that's a lot of torque to twist apart something that size! it's not huge, but big enough to make you say "whoa!" and is that a cracked transmission case i see in the first pic?

 

Wow. epic breakage.

 

I want to hear more about the 273 install! Looks good.

 

Whats the 273 out of? It looks to be a chain driven box to me, I dont know is why i'm asking. Is this box stouter than the original t-case? Pulling will find alot of weak links quick. Then when you get all the weak links fixed it starts all over with just a little additional power. Good luck-hope ya win em all.

 

I've seen a 1.25" input shaft off of a 2500 cummins "torsioned" and broke the same way, it brings the woah out of people.
the 273 seems to have a deeper drop than the 205: is it the angle it's mounted at? In your application (pulling) you don't really need a skid plate, but if you had to add one, wouldn't your clearance be lower than with a 205?
the 273 is an aluminum case right? and chain-driven? I guess the weight gain might be one reason.

 

Broken parts are no fun, but like Scars, they make cool stories!

 

The 273 is out of a ford. It is at a funny angle because with the 6 mounting bolts you only have so many choices. That's the only one that would work with out a lot of modification.
There is not enough material to re-drill the holes where you need them for a factory looking install. You would have to basically weld up new bosses, drill them and then have the face of the case milled. By putting it where we did we only had to re-drill 2 holes in the existing pad's.

Anyways there is no doubt this thing is way stronger than a 205. The main shaft is over 2" diameter. This is what comes factory in the newer diesels.

Here's a comparison of the two:
http://www.pirate4x4.com/forum/showthread.php?p=9562416

Yeah it is aluminum chain driven. And it still weighs almost as much as the 205. I am not knocking a 205 at all. But they have a crummy low range for what I need. The gear drive will blow the case apart when it is over stressed. The 271 has planetary reduction, much stronger. It is also crazy simple inside, there's like 5 things in there. It is big thought. 24" from front to back. I don't know how wide it is, but I don't think it would fit up in the frame.

No cracks in the tranny that I know of. You might be seeing the sealer on the tailhousing? Or that x brace thing on it?

 

the pic showing the difference between 205 and 271/3 speaks for itself...
That np271 you got has a 29 spline input shaft or did you have to change shaft and/or coupler?
It is a passenger side drop, right? did you re-route your exhaust?
nice work on the torsion bars mounts on the frame: it deals with both front and rear, right?
one last one: I don't know jack about sled pulling, but I gather you put the truck in 4-lo and 1st gear or else?
Thanks!

 

The t-case came with a 31 spline input gear I think. I had to get a 29 spline input gear for it. I got it from ZBAG.COM You can put the dodge input in the ford case. It is really easy, you just have to completly tear it apart to change it though.

Yeah it's a pass side drop, now. A superduty is drivers side drop, just like the 2nd and 3rd gen ctd's. You have to redo the oil pump pickup, since it is basically upside down.

It just has a hood stack on it, no exhaust underneath. We have it, but just took it off cause it looks goofy with all 3.The bracket's are for front and rear traction bars. With the 2.71:1 low range we are planning on running 3rd gear-4lo for the right balance of power and speed.

 

Keep up the drivetrain/pulling R&D! One of these days I'll be coming back to your threads for help etc.

Figure out the whole external 35 spline drive flange setup? I read it's NLA via Spicer. Custom produced only?

 

We are getting the 35 spline shafts. Just don't know whether to get the Spicer's or the Yukon's.

The drive flanges were a pita with a welded diff. I really want to run lockout's. What kind to get?

 

Spicer all the way. Warn premium lockouts pricey but a must if you want to be able to steer with the welded diff. Is it just a simple switch to the internal lockouts or do you have to switch to the spline hub?

 

You have to switch the hubs to the newer style. Going to get GM ones.

Here is some better pics of the t-case.











We tore the other side apart, and that shaft was twisted too.