transfercase reduction

[lantz84]

Any body know of a tcase reduction kit? i wouldnt mind a doubler but not sure if i want to bite into something like that..didnt know if there is a gear reduction kit out there or not

 

[Evan]

There is no reduction kit for RBV transfer cases. If you want more reduction, you need to swap a regeared Dana 300 or Atlas in. You can also build a doubler.

By gearing down the axles a bit you can get pretty good reduction out of an RBV with a stock case.

 

[lantz84]

i would love a doubler but how much trouble are they to build? im running 44/9in with 4:56 and 35s which is nice on the road but just not enough offroad..will the 300 bolt to my tranny or do you have to use an adapter

 

[Evan]

i would love a doubler but how much trouble are they to build? im running 44/9in with 4:56 and 35s which is nice on the road but just not enough offroad..will the 300 bolt to my tranny or do you have to use an adapter

Counting the case, flip kit, 4:1 gears, and adapter plate, you can easily spend over $1000 for a Dana 300. A D300 swap involves a decent amount of work and a pretty high cost.

Building a doubler involves quite a bit of work. Between gathering parts, building the doubler, and installing it, I probably spent about 5 full days on it. A doubler can be built for a fairly low cost, but it's a lot of work.

An Atlas is the least amount of work, but it's the most expensive option.

 

[lantz84]

did you pretty much follow what they have posted in the tech library or is there a better way to go

 

[Evan]

did you pretty much follow what they have posted in the tech library or is there a better way to go

I wrote the article in the tech library.

The method described there (BW1350 manual into a BW1354) is pretty much the best and most cost effective way to build an RBV doubler. About the only thing you could improve would be to get a 1-piece sector shaft made from scratch. Although if you make the 2-piece correctly it's quite strong. I've never broken mine, and several other people (Todd for example) run them successfully.

 

[lantz84]

would you have a more detailed write up of it? i decent when i comes to creating stuff...if i know how it works...but i havent taken a tcase apart so i am still very much in the dark..which i feel like a retard...i put my truck on a 44/9in set up yet im scared to death to make a doubler..hmm

 

[Evan]

would you have a more detailed write up of it? i decent when i comes to creating stuff...if i know how it works...but i havent taken a tcase apart so i am still very much in the dark..which i feel like a retard...i put my truck on a 44/9in set up yet im scared to death to make a doubler..hmm

That writeup is pretty detailed. I don't have anything better. Between the writeup, and the exploded view of the 1350 in the tech library, you should be able to figure everything out. And you can always ask for help on here. Several guys have built the exact same setup.

The first step is to gather all the parts. You need a 1350 manual, the steel plate, and a 4x4 output. Then tear into the 1350. These t-cases aren't all that complicated.

 

[4x4junkie]

Agreed, I have a doubler in mine also. Mine I bought a kit for, but really all it was was just a couple plates that would not be hard to copy, and a one-piece shaft (I still had to procure a case and "cut" it in half). Internally the cases are dirt-simple. The whole gear reduction unit is self-contained, no springs, washers or anything that need to be dealt with separately, basically it's just slap the reduction unit ahead of your existing case and go.



The biggest thing will be to make sure the cases are centered on each other when making the adapter plates (and of course that everything is sealed well).
I would think that assembling the two cases together on the shaft, then wiggling (sliding) them around noting how much it moves in all directions (marking it as you go), and then centering it as best you can within your markings would give satisfactory alignment.

 

[F150hybred]

Sure would be nice if someone would come up with a kit to replace the reduction unit. **SIGH** You know... like the ones for the other cases.... come to think of it, they make one for a Suzuki... and yet, nothing for us!
It wouldn't be hard either... just a new reduction gear set. Not like it's rocket science either!

 

[4x4junkie]

Suzukis don't use a planetary gearset.

AFAIK, the ONLY case with planetaries to ever get an aftermarket gear reduction was the Jeep NP-231, and we all know what the market is like for those...

It's not as easy to make lower gearing fit within the space of the stock planetary gears (and maintain sufficient strength, anyway).

 

[F150hybred]

Still.... you gotta admit, it WOULD be nice. I'm sure if someone produced such a unit in... let's say quantities of 100, they wouldn't last long,

 

[lantz84]

well thanks for your help i may just go ahead and do it..it sucks man i just sold a manual 1350 with a tranny i had..oh well. Does anybody make a one piece stub shaft or is what yall using working pretty good?