Would it be feasable to link 2 tcases together on a 94 s10 blazer? I would like to keep the stock tcase (np231?) and put a np205 on the back of it. If so how is it done or is there a link for intructions? I am also wondering if there is a reduction gear kit for the np231 that would bring it to a 4:1 ratio or better.

If my gear ratios are correct for the 700r4 tranny that would bring me to about a 142:1 final drive in 1st gear with 5.13 gears in the axles.  

Where is the world do you get 142 to 1????. If it were opossible to do as you suggest, it would be about 80 to 1. Also a 231 or 241 and a early NV4500 with 5.13 gears would give you about 88 to 1 which is plenty deep.  

3.06 (700r4 1st gear) X 4 (tcase #1 np231 modded) X 2 (tcase #2 stock np205) X 5.13 (axle gears)= 125.5:1.

My first calcualtion was mis-calculated by using 3.46 for first gear in the 700r4.

Is my math wrong?

The reason why I want to use the np205 is because it should be strong enough to hold up to the 12.24 gear reduction from the tranny and tcase #1 and I have a friend that has a np205 for a chevy that will give it to me if I want it.  

I think you miss the whole point here. If you use proper axle ratios for tire size, even a 231 will hold up fine. People wreck Tcases and drive shafts because they do not properly regear axles. Also if you mod was possible, you would loose traction long before torque load on 205 was even a issue so not much torque would ever stack up on it. This would border on kinda a foolish mod. Lots or extra weight and shorter rear driveshaft with higher angle on it too.  

So what your saying is that there would be no need for me to run the 205 on the back of the 231? and all I would really need to do is mod the 231 with the 4:1 ratio (if possible) and run 5.13 gears in the axles?

Why do people run atlas 2 tcases? a neighbor of a friend of mine has one in a truck he is selling and said in double low it is 6.6:1 ruduction. His first gear final drive ratio is ~120:1. His truck was pro built and he "said" he had $25k invested in it.  

that low of gearing enables you to have more control in certain situations.ex, a 2 to 1 gear will want to cover more ground with "x" rpm,so a 3 to 1 will cover less ground per given RPM. and so on say you got  REALLY LOW t-case reduction,it'll jes crawl,you have to give it gas to go any where,which is exactly whatcha want in technical stuff where you dont have to ride the brake to slow you down and keep you from hitting the obstacle harder,or too fast and tipping you over,imagine creeping up to a "stairstep" obstical just like it sounds just taller,,gots your low low gearing ,you sneak up and bump it and then a likkle gas and it pulls you over slowly as you want,you want control here,now picture going up to the same step in a higher gear,your idling along at 3 mph you brake as you bump the wall and then mash the gas and bounce up and over...not very elegant and people gonna stare,you didnt have as much control over your wagon as you could have. now, remember the torque multiplication we talked about? well now youve got less cause your in higher gears,so's ya have to rev it,making your wagon not so controlable,but if you had lower gears you dont rev as much to get the same torque output,see what ime getting at? ime sure someone could say all that in a word or two,but hey. another thing off road torque is king,ya can build a monster 800 horse 454,but the motive force will be way up in the rpm range ,way out of where it will be of any real use,iffin your building bogzilla yea, go for it,but if ya want to Kreep and Krawl like the rock star you are,and show your buddies how smoove you drive and spoil them for all the other guys making a show of how try hard they are gear down and play!build for whatcha gonna run ,an all around mochine is cool but it is a compromise in all areas ,a rock crawler has different operating peramaters than a bogger,vs a sand rig vs,etc and if your gonna be on the streets most of the time ,well 5.13 gears and 44 inch hawgs are gonna eat your lunch.i forget what the stock low is on a 231 but have you played in the mud ,rocks,sand, yet,youd be suprised how low it is,but ime not one to knock gearing,its a good thing as MARFA Steward says! happy wheelin  

The stock ratio on the 231 is 2.72:1 which is nice already. You said it just as i understand it if I have 2 tcases and an auto trans I can select for the type of terrain Im going to be in if I run the 231 in high and the 205 in low I can turn the wheels faster for mud if I have the 231 in 4:1 and the 205 in 2:1 I can crawl like you said or if I want I can run the 205 in high and the 231 in 4:1, I can. I think it would be very versitile. But as snoman has stated the wheel base on the 2 door s10 blazer will be too short... what about a 4 door s10 blazer?

I am already set on having 5.13 gears for the axles and a 4:1 mod for the 231 (if available) with the 700r4 tranny I would like to run 40s or if possible 44s (stock d60 and 14 bolt) 5.13 X 4 X 3.08 = ~63:1... I would like to double that and I already have access to a chevy np205. I could see the 63:1 be very acceptable for 33s or 35s but I dont think it would be great for the 40s or 44s.  

A problem or two,not tryin to discourage ya,1. like snoman said,length,in a small S10 your gonna throw the shaft length on the rear off,your drive shaft has to work in a range of angles b4 the u joints bind,now, that can sometimes be fixed with a special driveshaft,cant remeber the name but "HIGH ANGLE DRIVELINE" is the name of one of the companys that make one. also it wont be as strong when your mudzilla grabs traction the u joints are Fuses,they go first b4 something expensive gives.
2. the 231 is a lighter duty case that may not be able to withstand the same structural/torsional stresses as the cast iron 205. what the 205 will take and grin may rip(no kidding) the aluminum case of the 231. theres a four to one kit from terraflex advertised for 1100.00 dollars in four wheel and off roaders dot..
nothing  is impossible,a 4 door baby blazer may give ya a foot or so extra length,its still a small truck so you can get away with getting round,but, a 4500, or 5600 six speed tranny will give ya a wide gear spread to choose from. with a 205 containing a 3 or 4 to 1 reduction kit it'll be less complicated. the more equipmment you stack behind each other, to a point,is one more thing to break. and there is the essence of wheelin.keep it simple. u can have two drivers, one is well versed in four wheelin technique, the other can have  all the best equipment.switch trucks between them and most likely the outcome will be the driver who wheels smarter in any vehicle wins.
wheel speed is determined by how much motor you got to spin them some gumbo mud will suck the tires down and will need brute power to muscle them .gearing does multiply force,but there has to be enough to do the job.then there is breakage issues,everything breaks,the bigger tires will exert great force,and an axle will break coz it binds and too much force is applied,or you hit traction and again too much force is applied.think about a manual tranny to have the option to gear on the fly w/o having to move a bunch of levers/ maybe stop t shift the levers b4 you hit where your going,just some thoughts,happy wheelin!  

For 44's what you really need is deeper axle gears to limit chassis counter torque and drive shaft torque not a extra Tcase. 6.14's would be about right for 44's.  

I was under the impression that 5.13 was the deepest gear you could fit in a 14 bolt with out changing the carrier. I have not looked to see for sure. That was why I was limiting my axle ratio to 5.13. If it is not I would definatly go deeper in the axle.

I am very lazy so a manual tranny is not an option for me...


Honestly I think the s10 blazer is out anyways unless I cant find a 700r4 in the salvage yard. I was looking yesterday and found an adapter kit to run a 700r4 tranny on my 401 in my waggy. A friend of mine said he knows where I can get a (I think) np208 and np205 hermaphrodite for around 500 shipped. It will give me the option of 7:1 ratio or 4.5:1 or 2.5:1 and will only be about 1 inch longer than a strock 208 and be all gear drive.  

14 bolt is limited to 5.38. The 14 FF is a good axle but generally when you are in the 44 inch range you are past 14 bolts (because of strength and gear ratio limitations) and into Spice 70 and 80's in rear and D60's or better in front (or rockwells) because those spicer axle can go deeper. BTW, carrier is not the limitation with 14 bolt FF, it is the straddle mounted pinion design that limits minimum pinion gear size.  

I know where i can get some 2.5 ton axles cheap (free maybe) but if I go that route I will be building a dedicated buggy and needing to find something that can tow it not to mention I would prolly be going with a 54 inch tire.


Is the d60 stronger than a 14 bolt?

I am not set on 44s either... I would be happy with 40s.  

I would say no on D60 as they are about equal with maybe a very slight edge to 14 bolt. But I would say yes to a D70 being stronger. D60's and 70's can be had in 5.38, 5.86, 6.17 and 7.17 ratios.  

What kind of vehicle would I be looking for to find a d70?  

Some 70's to 80's GM 1 ton SRW (single rear wheel) had them and pretty much all dualies had them up into 90's or so.  (with dualie you could change hub)