Transmission Tansfercase Questions

[82 Silverado 4X]

This much I do know. I have an 82 Chevy 1/2 ton 4x4 with the NP208 transfer case and auto hubs. The transmission in my truck is a manual with granny low gear (465 right?).
I have what has been identified as a 1980 NP205 with the slip yoke rear output that's mated to a 465 manual transmission that's been laying out in my garage for over 5 years.
I would like to install the NP205 in my 82. The front driveshaft output plates are the same on both. The 208 has the similar design slip yoke rear driveshaft output like the one on the 205. The only obvious difference is the overall length of the transfercases and the adapters. The 208 with adapter is approx. 6-8 inches longer than the 205 with adapter. This I know would mean lengthening the rear driveshaft to make up the difference.
Am I missing something else or would this be a relatively simple changeover? Anyone done it?
If this can be done, my next move would be changing out the 1/2 ton axles and springs for some 3/4 or 1 tons.

Thanks for any and all input on this one.

[Pont]

I wish I could be more help George but I just don't know much about the newer style slip yoke t-cases. It sounds like a direct swap other than driveshaft length but I don't know for sure. You might check with Blazer1970, it seems like I remember him being really knowledgeable on the newer applications. I could be wrong about that also. LOL, sorry I'm not much help........

[82 Silverado 4X]

That's Ok. Hopefully someone will come up with an answer. I'd really like to pull off this swap.

[6869704X4]

Couple of questions.
Are you planning on doing this in two stages? If your truck is driveable keep driving it while you look for axles.
Are you going to keep the slip yoke on the 205? Since you have to get a new driveshaft now is a good time to convert to fixed yoke with bigger u-joints for your planned bigger axles. Get the front drive shaft setup for the bigger u-joints too.
Im suggesting doing this all at once to minimize the down time.
Make sense?
Good luck.

[HeavyK20]

One minor issue is the hole location for the shifter. Another thing to check is the cross member and mounts. I would think they are the same but I don't know for sure

[82 Silverado 4X]

6869704x4:
Now that you mention it, I do like your idea of doing it all in one stage instead of doing it in two. If I'm going to go for it, I'll get the axles, springs and everything else I"ll need before I begin tearing it down. I still have my van to drive and a trailer to pull it with as long as there is no snow. A 1 month summer down time wouldn't be a problem.
I would first like to try to look for axles, springs and driveshafts from a 1980 3/4 or 1 ton 4x4 LWB to eliminate as many of the conversion differences as possible.

HeavyK20:
I have the crossmember/mount for the 1980 setup. Relocating holes in the frame shouldn't be a problem. If I can't get the hump cover from a 1980 when I get the axles and springs, I'll probably need to modify my 82 cover plate for the NP205 shifter. I have metal working tools and a mig if I need to cut and patch.

3 More questions:

1. If I can't find a complete 1980 axles, springs and driveshaft setup, can my 1980 slip yoke NP205 be converted to accept the straight yoke set-up from other years or would it be more trouble/expense than it's worth?

2. Did GM use different types of axles in 1980 3/4 and 1 ton 4x4 trucks and if so which type is more preferable (heavier) over the others?

3. My truck is a "very solid" daily work driver but will never be a show truck. When I bought it I never planned on dong anything more to it than just use it to get to and from work in the snow. Since then it has taken on a few extra duties. I don't do any hill or rock climbing but I do take it off road. Quite often I go back in the woods to haul out logs or use it tow a heavy utility trailer with my Bobcat off the pavement. In this capacity the 1/2 ton with the NP208 setup isn't heavy enough. That's why I'm looking into this change over. With that in mind is the 1980 slip type yoke output heavy enough for this "general purpose use" or is it considered weak like the NP208?

All opinions on this are greatly appreciated.

[twistedmetal]

dana 44 front diff that came on 3/4 tons is the same as the 1/2 ton one i do believe the spindles and hubs were the only change(8 bolt hub).the one tons came with the much heavier dana 60 front diff.am unsure but just what i heard from some avid off-roaders when i asked the question of heavy diffs for my truck.Up here we have run one of our trucks with 208 and 1/2 ton diffs.we've torchered the hell outa this truck in the sand hills and many mudbogs the transfer case had a quite a few miles on it when we threw it in.we are running 44's on this truck with too high of gearing,and a 520 hp 454 ,we've never touched the transfer case but keep going through diff housings axels and carriers from jumps catwalking and coming down hard.i'd probably change diffs but not worry about transfer case,unless you are gonna have a 750 hp alcohol burner under the hood.This is all just our experiences,might just have a rare good t-case from the factory.

If I had a dollar for every Dana 44 i blew,I'd have my locker right now and not my welded gears

[6869704X4]

Originally posted by 82 Silverado 4X
1. If I can't find a complete 1980 axles, springs and driveshaft setup, can my 1980 slip yoke NP205 be converted to accept the straight yoke set-up from other years or would it be more trouble/expense than it's worth?

Thats what I was asking about. Ive seen kits to do it but didnt pay close attention. I dont know if its stronger but if you were to break a rear u-joint for example you could take the rear driveshaft off and get home in front wheel drive.
Have you been to http://coloradok5.com/ ? Those guys do this stuff a lot.

[1969 GMC]

If you want to upgrade to heavier axles, your best bet would be to set your truck up like a factory 1-ton 4x4. Get the dana 60 frontend, this might be hard to find and pricey, but worth it. Perhaps even a dana 70 frontend, but these are even rarer, and if you see one with closed knuckles just pass it by. For the rear, the corp. 14-bolt is probably the best way to go, it is very popular, and easy to find parts for. Of course, you could also go with a dana 60 or 70, depending on if you could locate them. corp 14 bolt and dana 70 are comparable in size and toughness, dana 60 is "weaker" than those two but still plenty strong. It's also a good thing to check spline count, too.

[Blazer1970]

The only issue besides driveshaft lengths as you have already noted, would be the tranny output and t-case input. I am not sure whether they match or not. I think the 1980 205 still used the old 10 spline connection with male shafts on both tranny and t-case, and a sleeve connecting the two. This is easy for you to tell because you have the t-case already loose. At some point, they went to a 32 spline output on the 465 trannies, which would mate to a 32 spline female input on the t-case. I am not sure what your '82 truck will have. If you have the 32 spline now, the swap becomes a little more complicated.

[82 Silverado 4X]

Tim
The NP 205 and the 465 I have in my garage came out of the same 1980 truck and it does have the 10 spline sleeve between the trans and T.Case. I have no idea what the spline count is on the 4 speed that's in my 82 truck. But even if my 82 setup had a different spline I could always use both the 1980 transmission and transfercase when I do the change-over.
I've printed out axle information and will use it when I go in search for my new set-up.
Thank You "Everyone" for the advice. Hopefully I'll have everything ready for the changeover before the end of summer.
I'm sure that's when I'll have some "really hard questions" for you guys.

[ozarkhippie]

wish you were closer I could fix you up with all 1 ton axles and drive shafts and trans and transfer parts, frame, 82 1 ton title, ect.

[82 Silverado 4X]

Wish I were closer too. It would be alot easier than scouting out the parts at all the hornet infested boneyards.