Transfer cases! SOS!!

[willett]

Hi guys,

I need to find a T case for my '78 454/TH400. I currently have an NP203 which is starting to sound very unhappy.

I am currently scouring craigslist trying to find an NP205. I know that I will need a 32 spline but what about te different bolt configuratios?? Is the figure 8 only found on late 80's/90's trannys? (460le)
First off it should be known that I am NOT looking for parts from the board as I am not a paying member and it is against the rules.

Is there an easy way to adapt an NP205 t case from a TH350 or 700R4 to fit my TH400?
I found a place online that sells input shafts for about $150. Is that all that I need to do, or are there other aspects that need to be modified?

Once the t case is in how do I determine necessary drive shaft lengths? (single cab long box)


How do I determine between a 205 and a 208? Is there any aluminum on a 205 case?

Thanks,
Spencer
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[willett]

It should be known that I am NOT looking for parts on this board as I am not a paying member and it is against the rules.
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[b454rat]

Whatever t-case you do find, it will not work with your current tranny. Your combo has the shortest output of them all, and will have to swap to another output to use any other t-case.

Best bet is to rebuild the current 203...

[kwmech]

You will need the 400/205 adapter and a turbo 400/205 output shaft, (a 2wd short shaft will work also). If you cannot find a figure 8, 32 spline t-case. You can have a 27 or 10 spline case gutted, machined and rebuilt with the correct input gear and bearing

[willett]

This is not sounding good. How labour intensive is it to swap the trans output?
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[willett]

Anybody know of someone who sells a 203 rebuild kit?
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[b454rat]

Check with this place..http://www.offroaddesign.com/catalog...rcaseparts.htm

[willett]

I see 2 things on there that look helpful

NP205 input conversion Kit:

Convert your male input NP205 to a TH400 version 32 spline short female input gear. Kit includes new input gear, input bearing, input bearing snap rings and a complete seal and gasket kit. Requires machine work on the NP205 case to install, the input bearing bore must be enlarged by about 3/8" compared to the small bearing.

Okay, Makes sense. Is there such thing as a factory 205 that already has this style of input, or did GM just flat out NEVER put a truck out with a 400/205 combo?



NP205 transfer case adapter housings:

TH400 to NP205 figure 8 bolt pattern #GU4032 - $250 (New high strength aluminum) Buy Now


Is the necessary to mate ANY 205 to my TH400, or is this for adapting a non-400 t case to fit a TH 400?


Sorry for being redundant, I just want to make as little confusuion as possible for myself.

[Livrat]

GM put factory T400/205's in the 1 ton duallys in the mid 80's, they are tough to find but they are out there.

The parts changing and machining only refer to a 350/205 setup

[willett]

So far I have only come across 205's off sm465's. Can I swap out the input shafts on those? Im an apprentice hd mechanic, the labour part isn't really a problem, I'm mostly concerned about keeping this as cheap as possible
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[b454rat]

You need to match the input with whatever t-case you go with, also need the matching adapter. GM made two different 400/205 combos, one that livrat mentioned, and then one from the late 70s. The 70s has a figure 8 pattern to it, and the 80s has 6 bolt round pattern to it. They are both getting tough to find, since they have been made since 1990. I've been out of the 4wd game for a bit, used to know all this stuff, but I can't remember squat anymore. Hope it's not a sign of old age...

[Livrat]

Originally Posted by willett

So far I have only come across 205's off sm465's. Can I swap out the input shafts on those? Im an apprentice hd mechanic, the labour part isn't really a problem, I'm mostly concerned about keeping this as cheap as possible
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Yes you can use a 205 off of a SM465, you will still need the figure 8 pattern T400 adapter (available aftermarket), a T400 input shaft and machine the 205 case to accept the 400 input bearing (the hole needs to enlargened 3/8")

[willett]

This is way more complicated than I originally thought.

Assuming my trans is the original from 1978 is it safe to say that I have a 6 bolt pattern on the trans?

Will a mid-70's 205 from a th400 be a direct bolt in is is an adapter still required?

I guess what I need to know is can I find an np205 that will not require and adapter, or will ANY 205 require an adapter on a TH400?




I'm seriously considering rebuilding my 203 at this point :|
It has been converted, but I think it was shimmed rather than having the shaft replaced because I'm noticing quite a bit of play in there. Is it true that the mile maker t case diff replacement shaft is about $400?

Will a mid-70's 205 from a th400 be a direct bolt in is is an adapter still required?
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[Chief_Wiggum]

Having just researched all this for my truck, I can tell you if you're looking to save money, swapping in the 205 will not be cheap. Finding a 32 spline female input GM 205 in the wild will be next to impossible as most of them are bought up by the rock crawling crowd for doublers. If you find a 10 spline 205 from behind a SM465, as Livrat has said, you'll need the adapter (at least $100), TH400 output shaft ($50 at least), 32 spline NP205 input shaft and the larger bearing ($190, plus the machine work), and finally you'll have to deal with the driveshafts. You could probably buy an entire used NP203 for $100 and a rebuild kit from eBay for $150 and have all the parts needed to fix yours. If you're not set on the 205, that would be the cheapest way to go.

[Livrat]

All TH400's have the same pattern, all 205's have an adapter (the large part that goes between the trans and transfer case.
Yes if you found a TH400 205 with the correct adapter it will bolt to your TH400.

The easiest way would be to find a 205 off of a 400.. but these are not easy to find and somewhat expensive.

The next way would be to purchase a 205 off of a SM 465. purchase all the necessary aftermarket parts (adapter,205 input and bearings) disassemble the 205, have the machine work done
All of which can get spendy

The most cost effective way would be rebuild your 203

[willett]

Thanks livrat. Very helpful! If you lived nearby I'd buy you a beer.
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[willett]

Found a th400/205 combo on cl for $600. Im thinking I'll buy it and flip the tranny
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[Rubble]

Willett,I sent you a pm,might be able to help.
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[dieseldawg142]

willett, i have one of the elusive factory 400/205 combo's in my 85 crew, if you need pic's or anything, i'm just down the road

[willett]

Thanks guys,

I'm going to check out the 400/205 combo out in Langley tonight. I have a buddy that wants the Tranny so i think its going to work out.

Will my current tailshaft work or am i going to have to swap that out too??

[b454rat]

If you mean the output shaft, no it will not work, too short. You need the tranny, adapter and t-case.

[willett]

t case and tranny will be complete so the adapter will be atached to the T case.


Since I will be buying the Tranny/adapter/tcase will it matter if the t case is a round pattern or figure 8? either configuration will be the same on the th400 side of the adapter... right???



fark! I think this guy just answered my question
http://www.sixfiveturbodiesel.com/showthread.php?t=1237

and this just asnwered my other question about how tough it is to swap out :|
http://www.jeepforum.com/forum/f8/th...moval-1050485/

my tranny was recently rebuilt, and upgraded,I don't really want to tear it down again, and I don't want to put a stock tranny back in... looks like my buddy is going to get the whole works



Now that I know all of this about th400/205's I think it will be A LOT cheaper for me to o'haul the 203 (as previously mentioned by cheif wiggum and I think somebody else)

A HUGE THANKS TO EVERYONE WHO HELPED ME ON HERE, I REALLY APRICIATE IT!!!


Keep your eyes peeled for my 20 questions about overhauling an NP203

[willett]

and thanks again for your patience guys.
I know I'm asking similiar questions over and over but I want to make sure I get this right so I don't end up with a truck in peices stranded in the driveway.

[b454rat]

I would get the 203 rebuilt, and get the output shaft to convert to part time. If you give ORD a call, they can hook you up on everything. They build doublers out of these cases, so they know what they are talking about.

[willett]

I should have mentioned that my 203 is part time and I have locking hubs already. Part of my original concern about the case is that the 203 diff is shimmed rather than replaced by the $400 milemaker shaft setup. I recon there is one of those in my near future as there is quite a bit of play in my case currently
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