q's about transfer cases and driveshaft(rear)

[benoit454]

Ok first off I have an 86 swb truck, 350 now with a 700r4 trans.

What transfer case do I have? I think it's aluminum, how can I be sure as to which it is? I can get pictures once it stops raining.

Ok now the tranny is slipping so i picked up a th400 and transfer case, supposedly out of a camper special 87 year model. It has an iron case because it's pretty damn heavy.

A little more info on that setup is..

it has the transmission to transfer case adapter or whatever, with the corssmember made to that, or bolted to it, and it's made like a normal crossmember, flat goes from frame rail to frame rail and bolts on, but it also goes back like under the transfer case, and has another crossmember, that bolts up the same way.

So in short the crossmember on it is H shaped.

What transfer case does the th400 have? how can I tell.?

Here's more info, the th400 transfer case has a bolt on style rear driveshaft, meaning the u joint bolts on with the u bolts, then the driveshaft hooks to the u joint. It also has a 6 bolt side cover that allows you to bolt on a pto driveshaft unit, which we unbolted on the site where i got it.

There's lies my problem, my rear driveshaft now has the slip yoke or whatever on it, like a 2wd truck or car, the splined end slides into the transmission, in my case the transfer case.

Any ideas on how to fix this? Do I need a 2 piece rear driveshaft to fix it? If so what would fit or work?

I was told you need that slip joint or whatever like the front driveshaft to allow some give in it, to slide in or out a bit further.

Any ideas? or suggestions? I'm lost on what to do about the rear driveshaft, and maybe figure out a way to bolt it up in my truck, I think I can handle the mount issues, just need to find out about the rear driveshaft.

[benoit454]

Ok here's some pics of the th400 trans. and t-case....





now for the one that's in the truck behind the 700r4.

[Blazer1970]

The t-case that is in the truck now is an NP208. The one that you have with the TH400 is an NP203. The 203 is a full time case (no 2wd option). As for the drive shaft, you need to either have your shaft modified to add a slip joint and the proper yoke (probably 1350), or find a shaft from a similar truck that had a 203 to start with. You will not be able to find the exact shaft you need in a junkyard though since they never made a short bed truck with a 1350 u-joint. The TH400 was 3/4 and 1 ton only, meaning long bed only. You could find a '73 - '79 short bed 4x4 and grab the rear shaft and the output yoke from the NP203 (1310) and use it all in your conversion.

[benoit454]

Damn it'll only run 4x4 then all the time?????????

That freakin sucks, maybe I'll leave out the front driveshaft then. I have part of the original driveshaft LOL.

[6T8]

My advice would be to fix 700r4. I know some have had trouble with 203tc when not hooked to front. There is a kit you can out in to make it compatible with lockout hubs. Don't know how hard to install. I'm sure you'll get more input from other members.....just my 2c.........Rick

[benoit454]

so it's not compatible with lock in lock out hubs either?

Man this is BS I'm about to return the damn thing.

I HATE my 700r4 JUNK, and I DO NOT want to use the POS but it looks like it's either use that POS or sell the truck.

[rcbildr]

Another option would be to adapt the NP-208 to the TH-400. You will have to change the input gear of the NP-208. Right now it has a 27 spline input and to mate up with the TH-400 it will need a 32 pline input. I had to do that when I converted my 85 Burb to a manual tranny. The job is pretty easy to do. The only part I'm not sure about is which t-case adapter to use. The other part of the conversion would be to set up the kickdown switch for the TH-400....hopefully someone else can help with that. You may have to modify your diveshafts too.

I can't remember right now the name of the place I bought the input gear for my t-case, but they had the best price when I was shopping for mine. If you're interested, send me an email and I will look around for it. Hope this helps.

[special-K]

I might be confused,but why wouldn`t you use what you bought?It`s a TH400/NP 205 already mated and you have the crossmember.All you need is the rear driveshaft from a longbed (w/205) and have it shortened.See if the guy that sold the combo has the shaft.

[6T8]

I believe it's a 203 instead of 205. If it was a 205 then that would of been the way to go............Rick

[benoit454]

Yea it's a 203 with the pto on the side and all that crap.

It's a full time unit also.

Anyone know how to tell if it's got a part time kit installed with it out of the truck?

I already checked on the adapter plate you'd use the th400 to 208 one but I don't know on the long or short probably short.

Also kick down is not a concern to me right now. My 700 r4 doesn't have a passing gear at all anymore.

[MylilBowTie]

The kickdown on a th400 is simple. It only shifts from 3rd to 1st and low speeds. The transmission itself should shift from 3rd to 2nd on its own, with or without the kickdown silonoid hooked up.

[Mudder]

Those part time conversion gears are not big deal. I have had one in mine forever and had no problems with it. I have never put one in myself but I believe they are pretty easy.

[benoit454]

My dad is just gonna trade the th400 and 203 for a good rebuilt th350 and cut down shaft to bolt in place of his 700r4 or have his 700 completely rebuilt with everything new in it, so either a rebuilt 350 or 700 for the th400.

[benoit454]

Thanks for the help and reply guys, but here's the conclusion....

The th400 is junk, bellhousing has a 6 inch long crack in it, and stress/heat cracks down where the bellhousing meets the body of the tranny.

My old man is gonna trade it to his tbuddy who owns a tranny shop for a rebuilt 350, 700, or maybe a 2004r tranny he already has rebuilt. Then return the transfer case for partial refund or something from who we got it from.

Also found out the TC was a 9 inch and had about a 2500 stall or so. He told me it work in my monte carlo so looks like I'll be keeping it for use on my th350 in my car.