4by4 conversion

QUestion to anyone who may help.
We have a 1980 chevy 4by 4. It came with a 203 transfer case. It has a turbo 350 trans. we converted it to a 208 transfer case. The transfer case
fits ok as we had to buy spacer to make it fit as the tailshaft was to long. We had the long tail shaft put in when we had it rebuilt antisipating putting in the 208.
The problem we have now is mounting the tranfer case to the frame. The adapter is for a 704 trans.
Is there a crossmember that I can hunt for that will bolt up, or do we have to have one made.
Also we have a 3 inch body lift on it, and a a 8inch frame lift on the front, 4 in spacers on the rear.. We are concerned about the angles of the driveshaft's
Thanks for any ideas...
Joseph snipped-for-privacy@cfl.rr.com
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I'm a little confused at what you're asking. Well, what are you asking is what I mean. Are you converting a 1980 2wd to a 4wd? or just modifying an existing 4x4? But I do know that all GM/Chevy 4x4's came with a NP205 transfercase from the factory. So it's either not an '80 or not the original transfercase.
The lift, do you mean suspension lift, rather than frame lift? are they 8" lift springs or 8" drop shackles. And a 4" block in the rear. If it were me I'd equal the amount of lift front to rear, or else It'd just look funny. The body lift doesn't affect that measurement as it's above the frame. If the truck rides level now, it's likely you've just got a 4" lift in the suspension. That should be fine for the drive shafts, there should be enough in the slip joints to lengthen out the difference. But If you've actually got 8" of lift in the front, you'll need to have your drive shaft lengthened.
The transmission should have a crossmember under it where it's rubber mounted. There is no crossmember for the transfercase, it hangs off the back of the transmission Unless you've got a divorced setup, then you'll have to fabricate a crossmember and mount for the transfercase.
Hope this helps out some.

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WRONG!!!
NP205's disappeared from being in all capacity and all trans application trucks in '72! NP203 cases were the dominant case of the 70's. NP205's being mostly 1T and manual trans applications. The NP208 was an 81 or 82 introduction with the 205 still in the HD wings. These are not absolutes...
The cross member is supporting the plate that joins the trans and the t-case. Their is a 'riser' extending from the cross member to the points where the trans and 'case mate and is matched to the 'case. THAT is where the cross member needs to originate from...If its an NP208 'case, get the cross member from a donor vehicle that had an NP208!
As for whatever setup you have for a lift... If you are concerned about driveline angles, drop the drive train! Lower the trans/t-case cross member and lower the engine mounting points! Lowering the engine mounting points is by FAR the more difficult of the two.
I am sure at least SOME of this will be corrected by a few Gurus in this NG, but I hope I am at least close...Doc, Gary...have at it!!!
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I dunno what your gonna run for a powerplant, but I would stick with the NP203!!! Its stronger, in my oppinion!

applications. The NP208 was an 81 or 82

absolutes...
t-case. Their is a 'riser' extending

matched to the 'case. THAT is where

cross member from a donor vehicle

Ok you are correct, as I knew I was on the 203. It did come with a 203 Cast Iron unit.. Also the Rear driveshaft that was on it did have a slip yoke, but now that I have the 208 I cannot use that one as the 208 has a tail shaft, where as the 203 required the slip yoke type. I will have to modify the existing rear shaft, or get a different one..
We don't know what the T-case came out of..

driveline angles, drop the drive

points! Lowering the engine mounting

We put an 8" lift on the front end. Meaning we installed taller springs, and wedges under them the angle the differential upwards toward the rear.
We lifted the drive line manually from underneath with a bottle jack and 2x4's in order to get the driveline fairly even to give it a look see and to see what we were gonna need to mount it, and to at least have it horizontal to the frame as it was before, and it looks like we are lacking 4" or so. We have another 1980 4x4 UNmodified to look at the angles.
We knew going into this that we had to make Mods, we just are stuck at the moment as to what to do short of bringing it to someone to make a mount & crossmember.
Thsi vehicle has 38x1250x15 tires. Also this will be for Mud racing only.
I appreciate any replies and ideas. Thank you,
Joseph

this NG, but I hope I am at least

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Ah yes, I was thinking about the mounts on a 2wd being under the tranny. Still doesn't change the fact that all 4wd's in 1980 had a 205. A 203 is chain driven and inherently weaker than the gear driven 205.

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IN 1981 OR 1982 AND UP INTO 88(I think, then the 241) THE NP208 TRANSFER CASE WAS ALMOST SOLELY USED!!! THE NP 205 WAS ALMOST EXTINCT IN THE 80's!!! GET YOUR FACTS STRAIGHT BEFORE YOU POST AGAIN!!!
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CASE WAS ALMOST SOLELY USED!!! THE NP

<SNIP>
Shades, you are right about 1981-on but 1980 is a different thing. I have a 1980 and have found out that what Demon said is true. All of that year with 4X4 have the 205 tc regardless of transmission etc. At least I have never heard of any exeptions. Dale K.
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Shades, pull your head outta your ass.
I know the different applications. The 203 on autos and 205 on stick till '79 and 208s from '81 to '88 which was the crossover year into the 241's. But IN THE YEAR *1980* the 205 was used across the board, K5's inclusive.
You gettin' aggressive for any particular reason? How about you get all the facts before you post again. And have a nice day.

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If it's of any help:
I did an 8 K20 P/U with a TH400 that had a NP205 transfer case. It needed a trans rebuild, then the internal splines on the input drive gear in the transfer case wiped out. One day they will wipe out again, and the tranny shop will listen to me and replace the output shaft.
Also, replaced the clutch on:
A 1980 K20 P/U with a dump box on it, a 4 speed trans and a New Process 205 transfer case.
Just my devaluated $0.02
Refinish King

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ALRIGHTY!!! I will be calling my proctologist this morning!!! I was missing the all so important, and all so small part that you were talking **1980** ONLY!!!
My SINCERE apologies Demon!!!
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Maybe small, but seemingly most important, as thats what the OP said he had, which is why I brought it up. And I've had 2 '80 K25's 1 previously with a TH350/NP205 and 1 currently, SM465/NP205.

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I'll give you $10+$5 shipping for your SM465/NP205 :-) I want the linkage too.
~KJ~

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It's pointless to lift a truck to drop components. They make drive shafts that can handle insane angles, if he has problems he should look into shafts with double cardians joints on at least one end, and slip joints built into the shaft. He should also shorten his NP208/NP241 and put a yoke on it, (not slip yoke) so if he ever needs to pull the drive shaft & drive it, T-case fluid isn't pouring out of it.
~KJ~

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