Synchro NP205 Transfer Twin Stick Mod???

[BeXtreme]

By looking at bearing cover. Plus, it used to be "full time 4wd" and I added the locking hubs.

Vettepilot

Auto locking hubs didn't become an option until ~84'. All 4wd trucks in 1980 got an NP205. Mine was selectable front hubs(I still have the original spicer locking hubs on mine) and has the same cover that ORD says is for a Synchro 205(it isn't). If you still have your original figure 8 NP205 installed, it is almost assuredly not a synchro 205. The only squarebodies that got a synchro NP205 after 1981 are K30's that were optioned with auto locking hubs. All 1/2 ton and 3/4 ton squarebodies got NP208's after 81 and they are all synchronized.

 

[BeXtreme]

never heard of a 205 that was full time are you shore that it is a 205 and not a 203 they are both cast iron 205 is part time gear driven case 203 if a full time chain drive case with a removeable range box

He's using the wrong terminology. Someone must have retrofitted his Blazer with Auto Locking Hubs. All 4wd trucks in 1980 came with NP205's. You could not get a full time 4wd truck in 1980. Auto locking hubs were also not an option in 1980... so none of them came synchronized.

 

[BeXtreme]

https://www.gm.com/content/dam/comp...tion-kits/chevrolet/1980-Chevrolet-Blazer.pdf

You'll see by looking at the Vehicle Information Kit from GM in 1980. Only the NP205 was available and there was No available RPO option for auto locking hubs.

 

[Vettepilot]

I may be mixing up some of what I am stating with the 1976 Blazer I also had. It's a 69 year old memory to deal with here. The truck is stored 6 hours away at the moment.

So, here's what I know for certain:

1980 GMC Jimmy with 350 V8 and 205 transfer case.
Turbo 350
Locking hubs. (I thought I had installed these, but maybe not...)

So to clarify, are you saying this cannot be a synchro 205?? That would be great news.

The memory thing is bad. I actually rebuilt this transfer case and tranny, but that was 25 years ago and I cannot remember the details!! I do remember that unfortunately the truck has 3.08 gears...

Thanks so much for the answers!!

Edit to add: How do I verify it's non-synchro??

Vettepilot

 

[99xcss4]

Auto locking hubs didn't become an option until ~84'. All 4wd trucks in 1980 got an NP205. Mine was selectable front hubs(I still have the original spicer locking hubs on mine) and has the same cover that ORD says is for a Synchro 205(it isn't). If you still have your original figure 8 NP205 installed, it is almost assuredly not a synchro 205. The only squarebodies that got a synchro NP205 after 1981 are K30's that were optioned with auto locking hubs. All 1/2 ton and 3/4 ton squarebodies got NP208's after 81 and they are all synchronized.

I think 81 was the first year for auto lock hubs at least according to this it is

xc_hide_links_from_guests_guests_error_hide_media

i wonder what the difference is between the auto hubs and the drive flanges/slugs used on the full time 4x4s other then the fact that one is permanently locked I can not find the difference

 

[b454rat]

If the drivetrain is all original, then its not a synchro. As already mentioned, every 1980 4wd got a 205. Auto hubs didn't come out till 81 IIRC, and that is when the synchro 205 came out. Take a pic of the back aluminum cover. Make sure it's clean so we can see lol..

 

[Vettepilot]

Ok, thanks guys. I will update when I go pick it up out of storage, but it will be a bit.

Vettepilot