Re-Gearing

[Jimmyb]

Well currently the CJ7 has a mild setup. By mild I mean its not working well.

The motor pumps out into a Ford C6 auto box, with reduction being done by a NP205 case. The diffs are running 4.56 ratios as I didnt want to lose to much meat off the D44 crown wheel. All this adds up to a final ratio around the 21.99:1 which is crap by anyones terms.

So the new idea. Simple is buy a Atlas or Klune but very costly and wheres the fun in that.

Heres my theory, make a doubler. Get my hands on a NP203 box, split out the range selector section, grab a Stazworks adapter and in theory presto I have a 4:1 reduction with final output up to 44.87:1

So now to find a Np203.......

[Gildo]

What does a NP203 come in?

[Glenn]

Hey Jimmy, may sound silly but how about making your own transfer case, I thought about when I was off road racing, you don't need high range? don't need to disengage 4wd? then something like a chain driven single speed transfercase would be fairly simple to make, know anyone with a lathe?

[CJ6np435]

What kind of effect does the auto have on your overall ratio?

reason I ask, my manual tranny jeep has o/all in the vicinity of 80:1 (can't remember exact figures) and the 40 odd you mention still seems high.

pardon me if this is a dumb question to the enlightened, but I've never had an auto

[Jimmyb]

The theory is that a auto will double it, which is why my original 22:1 I thought wouldnt have been a prob.

No idea yet what a NP203 came in......

[CJ6np435]

Ok so with the doubler and auto you should achieve 88:1
is this even low enough?

I assume the auto is "slipping" or shearing the oil to achieve the reduction
does it get hot! and what do you do to combat this

[isleofman]

have you considered a flipped dana300?

peter henry

[Jimmyb]

Thats correct CJ6..... That will be low enough. As it stands, when you go to climb a flat face thats as big as the 42" rubber, it struggles a bit. Yes the auto gets hot, not too hot though, running twin coolers and going to get into cooling in more in this 2nd rebuild of the vehicle.

http://www.stazworks.com/images/d1.gif
Thats a stazworks adapter, connecting a NP203 front to a NP205 full case.

http://www.northwestfab.com/images/completekit.JPG
Or this kit from Northwest Fab, more expensive but more complete.

[Wooders]

Nah ditch the auto & tcase and get something that sghifts like this :
http://classicunimogs.com/images/diag_shifter2.jpg

[CJ6np435]

Some 203 info but you've probably already read it
http://www.4wheeloffroad.com/howto/47538/

[Jimmyb]

yeah read that thanks. Havnt found where I can get one but :( Found what doubler I am going to use, just need to find a case now.

[Laz]

Nah ditch the auto & tcase and get something that sghifts like this :
http://classicunimogs.com/images/diag_shifter2.jpg


Uni moggish...

[jap jeep]

If considering custom building a tcse you could mount a diff centre with a spool or
air locker. Modify flange end of pinion or fab an adaptor would be interesting for posible ratio changes.