I'm running a 700-4 to a 231/241 splitter but I want to step up to a Th400. I'm wondering what cases would have a 32spline input? I have a Th400-203 setup but did any of the Aluminum cases come behind 400's?

Yes, I am not sure which model but the late th400's in the 88 and 89 3500 trucks do have an aluminum tcase that was used with the IFS, besides that the 205

208s came behind 400s in m1008 (and I think CUCV)
I have also seen in bone yards PD 241s behind 400s
though officially it didnt exist there are plenty out there

I have one with a 205, one with a 208, and one with an NP241, which does officially exist.

Not sure what you mean by that.

Pass drop 208s and the 241--either pass drop or drivers drop.

I have a NP 241 stock also.

Thanks guys, I'm looking for an adapter and input shaft to reuse my 231 splitter box. I guess I'm looking for a 241 or a 208.

you want to keep the 231 forward box and put it on a 400?. If you want to use another splitter with the same gear ratio, get a 241 off an 88-90 chevy 3/4t 4wd. I don't know if the 241 input will swap into a 231 box, but duffy says they are the same planetary gear set. maybe he means the same ratio. you will have to ask around on that one.

208 and th400 is dirt common in just about every auto trans k20 from 81-up

jut as comon as 305 engines are, shoudl be able to getone for less than 100 bucks in a yard

I already have a 241 planetary in my 231 splitterbox. I made this one and I don't really want to go through that again. My other option is to use the 203 as my new splitter box but then I would have to make a new adapter to my flipped D300. Right now my setup works so I'm not in any big hurry but I figures I would start collecting the parts and rebuilding the TH400. I had a 208 but it was a 27 spline 4 bolt behind a TH350.

What's wrong with the 700R, John?

Nothing I'm just looking for more BEEF. I'm tired of having a list of things to fix after each outing. I've wheeled long enough I know what should work for me. The 700R is a through back from the days when it was going to be a driver. It's well past that by now:D In fact I just took my trailer for it's maden trip down to Flat Nasty. She's a full fledged trailer queen:rolleyes:

If your 700R works fine, I really don't think you're going to gain anything by going to a 400. It will cost you power, and you'll have a higher 1st gear ratio.

I used to be the anti-700 guy, and I still am when it comes to tow rigs and vehicles with masses of torque, but in your case, I really think it'll be fine. With the low range ratio that you have available, and keeping an eye on temperature, it just makes no sense at all for you to swap in my opinion.

Did you get your engine overheating shit fixed?

Sort of, I hacked up my front bumper to fit my new 8274 and had to leave my front skid plate off. That kind of helped the overheating at Flat Nasty. I need to work on that issue but it's way to cold out there right now to worry about it.

As for the trany, when do I ever leave well enough alone. With over 11 to 1 in double low I'm not really worried about losing my 3.06 1st gear. I have a 400, 203, and a 205 sitting on the garage floor right now. I'm just planning for the future. This thread might be a mute point anyway. I'm thinking of replacing my 231/241 with the 203 anyway. I also have a friend with a 2.75 1st gear planetary and a full manual rev valve body for the 400. I'm just kicking around ideas.:D

Tim we're headed to The Cliffs next Saturday if your junks running?!?!:flipoff2:

I wouldn't know if my junk is running or not. I haven't seen it since last August. Either way, I have plans next Saturday or I'd be more than happy to go.

I figured this would be an appropriate thread to ask this question in instead of making a whole new one for you Chevy guys...

'79 Chevy 3/4 Ton w/ TH400

FULL TIME 4wd

HI LOC
HI
N
LO
LO LOCK

(that may be "upside down" but you get the idea, i.e. lo is up and hi is back, either way thats the pattern at least lol)

What T-Case does this thing have?

203

I figured this would be an appropriate thread to ask this question in instead of making a whole new one for you Chevy guys...


Correct, go to the Newbie forum for Newbie questions, you horses ass.

So you're saying "correct" in reply to my statement of "...figured this would be an appropriate thread... ...instead of making a new one..."

But then going on and saying to bring "Newbie questions" to the Newbie forum...

Mind you this is after someone quickly and kindly answered the question for me... good thing I'm just the horse's ass and not the asshole... seeing as its already taken anyway... :flipoff2:

Thx again guys! :D

208 or 241

a 32 spline input shaft from a 241 will work in the 231. the "same" things in a 241 and 231 are the planetaries, meaning that the 231's that came behind 4.3's have the 6 planetary set that is in the 241. the others such as the two i have are the 3 planetary set. both are 2.72:1 low range. the other thing you will need to do is probably make an adapter, because your 231 is most likely a 5 bolt adapter, while anything that came behind a 400 will be 6 round or racetrack 8. i have heard that there are some 6 round 231's from s10's floating around, but i have not seen one yet. but i have only seen a few, and have only heard they are rare.

edit, you may also be able to find a 27 spline 400, i dont know how rare they are, but i do know i have seen one. it came with a 208 behind it, no idea what it came out of.

Yup the inputs will swap(I swapped my 27 spline for a 32 spline when I converted to an 80e), just watch that you don't get the wrong input as the p-drop inputs use a thinner bearing than the d-drop inputs on the 241's for GM's.

Yup the inputs will swap(I swapped my 27 spline for a 32 spline when I converted to an 80e), just watch that you don't get the wrong input as the p-drop inputs use a thinner bearing than the d-drop inputs on the 241's for GM's.

good to know, i didnt know that.

you can always slide a ford np205 in behind the th400, too... if its for a daily driver and you dont need that extra extra low range.

I would stay clear of the 2.75:1 Low gear set that your buddy has. its out of a 200r4, and isnt worth a lot, due to the design.. its more like tin, instead of steel.

and if your rockcrawling, who cares if you lose 3 more % engine power through the trans? sheesh, you make it up with gearing. you wont notice the difference with that low a gear.

use the 203 and put the 3:1 gears in it, then run the 205 with the stock 32 spline stuff and the 1.96:1 ratio... If thats not low enough, you can always get out and try to stop it.


Edit: to answer your question about what cases came behind the th400....
Dana 20
NP203
NP205
NP208
NP241
Maybe not factory, but using the same input from the 241...
NP246
NP243

you can always slide a ford np205 in behind the th400, too... if its for a daily driver and you dont need that extra extra low range.

I would stay clear of the 2.75:1 Low gear set that your buddy has. its out of a 200r4, and isnt worth a lot, due to the design.. its more like tin, instead of steel.

and if your rockcrawling, who cares if you lose 3 more % engine power through the trans? sheesh, you make it up with gearing. you wont notice the difference with that low a gear.

use the 203 and put the 3:1 gears in it, then run the 205 with the stock 32 spline stuff and the 1.96:1 ratio... If thats not low enough, you can always get out and try to stop it.

well, a 'stock' ford 205 will not bolt in due to the difference in the input shaft spline count. but i am sure you knew that. having seen pictures of his rig, i would assume it is not his DD. not to mention, he already has a doubler, and at ~7.4 low low range to boot.

in my build, i want a tranny i can install by myself without a jack, as well as a t-case or two. that i why i want 231's. 203's and 205's are old school, and heavy as hell. not to say they dont work, but just not for me. and in my case, with the little power of a 2.8, 73:1 just aint going to cut it in the serious stuff. i'm shooting for about 135:1. that should be enough to break my axles if i want to:D

well, a 'stock' ford 205 will not bolt in due to the difference in the input shaft spline count. but i am sure you knew that. having seen pictures of his rig, i would assume it is not his DD. not to mention, he already has a doubler, and at ~7.4 low low range to boot.

in my build, i want a tranny i can install by myself without a jack, as well as a t-case or two. that i why i want 231's. 203's and 205's are old school, and heavy as hell. not to say they dont work, but just not for me. and in my case, with the little power of a 2.8, 73:1 just aint going to cut it in the serious stuff. i'm shooting for about 135:1. that should be enough to break my axles if i want to:D

Youre quite right. to put the Ford 205 in behind a th400,all you would have to do is to drill about 6 holes, and install a short chevy th400 32 spline input, bolt it up to an NP208/np241 adapter and go.

For a light duty application like youre suggesting, i would think that the np231/300 combo would be more than adequate. or, you could add a klune.

Youre quite right. to put the Ford 205 in behind a th400,all you would have to do is to drill about 6 holes, and install a short chevy th400 32 spline input, bolt it up to an NP208/np241 adapter and go.

For a light duty application like youre suggesting, i would think that the np231/300 combo would be more than adequate. or, you could add a klune.

well, in his case, he has a doubler, in mine i dont want to spend any money and i have a few 231's. i am looking to be on the trail, doubled, 38.5' tsl'd and at least 3/4t axles for about $1500 including the vehicle. and half of that is the tires. i could probably add locked front, hydro assisted hysteer and a winch to that for about $2k total

I made my own doubler so I have all of $20 in the 231 box. I already have a NP241 6-pinion planetary in it so I guess I would just need the input shaft and adapter to make it work with the 400. I'm kind of leaning towards the 203-300 setup though. I think I can make the 203 doubler shorter then the 231, to make up for the longer 400. I haven't started measureing yet but one of these days I'll get to that projest.

Earlier this week I bought the 2.75 gear set and a full manual reverse pattern valve body for the TH400. They are both TCI pieces so they are alittle beefier then tin 200R4's. I have no history on the TH400 I have so I'll have to start by tearing into it and getting it back in shape before I worry about the doubler.

Right now it's cutting brakes, suck down winches, and hydroboost that are occuping my time.:shaking:

use the 203 and put the 3:1 gears in it, then run the 205 with the stock 32 spline stuff and the 1.96:1 ratio... If thats not low enough, you can always get out and try to stop it.


Edit: to answer your question about what cases came behind the th400....
Dana 20
NP203
NP205
NP208
NP241
Maybe not factory, but using the same input from the 241...
NP246
NP243

I don't think the 3:1 kit for the 203 is sold anymore. I could be wrong, but I believe it used to be Wagner machine that did sell it.

Also, since we are going to include TH400's used in non-GM's, don't forget the BW13-39 or wtf ever the quadratrac was. I do believe that both of these Jeep configurations have different bellhousing patterns, and definitely output shafts if not the entire rear of the case are different also.

I don't think the 3:1 kit for the 203 is sold anymore. I could be wrong, but I believe it used to be Wagner machine that did sell it.

Also, since we are going to include TH400's used in non-GM's, don't forget the BW13-39 or wtf ever the quadratrac was. I do believe that both of these Jeep configurations have different bellhousing patterns, and definitely output shafts if not the entire rear of the case are different also.

good catch...

only the output shafts were different, the output end of the case still had 6 bolts in all th400 applications, even though you could get a th400 for a v12 jag.... might be interesting to see a v12 in a rockcrawler, eh?

might be interesting to see a v12 in a rockcrawler, eh?

If I wanted to see something that didn't run, I'd just go in the back yard and stare at my junk :laughing:

lmao, mines in the front yard.. it doesnt have the power to climb the hill out back just now.