Author Topic: What Transmission and Tansfer Case do I have???  (Read 24964 times)

Offline Bobs85PU

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What Transmission and Tansfer Case do I have???
« on: March 14, 2012, 06:35:06 AM »
Recently, I obtained a 1980, 3/4T 4x4.

This is only the second Chevy Pickup I've owned, that I'm going to have to "build" back to highway condition.

I viewed a number of posts about transmission and Transfer Cases and am totally confused...I have no idea what components are present in my truck's drive line...Other than it has a manual floor shift transmission and manual transfer case...It also has locking hubs.

As this vehicle has sat unused for a number of years, I want to go through the drive line and replace all gaskets and seals, as it has been my experience that once I start driving the truck, every gasket and seal will start leaking...besides, I'd like to ensure the components are usable, or in need of a rebuild.

Right now, I feel I'm in over my head, but with the help of a year specific Service Manual and help from members of this website, I'll overcome my ignorance and the learning curve, and have a dependable vehicle when I'm done.

Here's a picture of the Transmission and Transfer Case:



By the by, the original cab was burned in an electrical fire...So, I have a real do-it-yourself project on my hands!!! :-\
« Last Edit: March 14, 2012, 06:36:46 AM by Bobs85PU »

Offline ehjorten

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Re: What Transmission and Tansfer Case do I have???
« Reply #1 on: March 14, 2012, 09:14:58 AM »
The transmission is a Muncie SM465.  It is a 4 speed with a compound first gear (gearing: 6.55, 3.58, 1.70, 1.00, 6.09R).  First gear is unsynchronized, but the rest do have synchros.

The transfer case looks to be a NP 205 due to what looks like the 'figure 8' adapter pattern.
-Erik-
1991 V3500 - Gen V TBI 454, 4L80E, NP205, 14 bolt FF, D60, 8" Lift on 35s
1977 K20 Silverado - 350, THM350, NP203, 14 bolt FF, D44, Stock Lift on 31s
1969 Chevelle Malibu Sport Coupe - EFI350, THM350
1968 Chevrolet Step-side Pickup - 300HP L6

Offline Engineer

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Re: What Transmission and Tansfer Case do I have???
« Reply #2 on: March 14, 2012, 06:48:21 PM »
Yup. SM465/NP205.

The strongest combo available for our squarebodys. :)

Should have a GM Corporate 10-bolt front axle, and the GM Corporate 14-bolt, 10.5", full float rear axle.
2002 Chevy 2500HD 4x4 8.1/ZF6sp RC/LB
2001 Chevy 2500HD 4x4 6.0/4L85E EC/SB
1997 Chevy Blazer 4x4
1994 Chevy K-2500 4x4 C6P 5.7/4L80E
1979 Chevy K-30 4x4 4sp 4.10
1977 Chevy K-30 4x4 4sp 4.10 454

Dad of an Eagle Scout, and a Life Scout

Offline Jason S

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Re: What Transmission and Tansfer Case do I have???
« Reply #3 on: March 14, 2012, 09:03:28 PM »
Welcome to the site. 

The SM465/NP205 you have are a very stout combination.

1973 GMC K2500, Super Custom, Camper Special, 350, TH350, NP203, 4.10's
1974 Chevrolet K10, Custom Deluxe, 350, SM465, NP203, 3.73's

"1) Peace through strength; 2) Trust but verify; 3) Beware of evil in the modern world"

Offline Bobs85PU

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Re: What Transmission and Tansfer Case do I have???
« Reply #4 on: March 15, 2012, 08:43:02 AM »
Yup. SM465/NP205.

The strongest combo available for our squarebodys. :)

Should have a GM Corporate 10-bolt front axle, and the GM Corporate 14-bolt, 10.5", full float rear axle.

It looks like that's what I have!!! Here's some pics:

Front manual hubs:



10-bolt front axle:



Rear axle end view:



Rear axle:



Another view of the Transfer Case:


Offline heavychevy91

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Re: What Transmission and Tansfer Case do I have???
« Reply #5 on: March 16, 2012, 05:16:23 PM »
Front axle is a Dana 44 with the factory Dana-Spicer locking hubs, Rear is a Corp. 14 Full Floater. If I had to guess you probably have 4.11 gears. As said you also have a NP205 transfer case and SM465 transmission. IIRC the transfer case is 1979-80 vintage due to the slip yoke of the 205. Someone will chime in if I am wrong.

Offline Engineer

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Re: What Transmission and Tansfer Case do I have???
« Reply #6 on: March 16, 2012, 06:01:37 PM »
That's a 10-bolt F/A. No doubt about it.
2002 Chevy 2500HD 4x4 8.1/ZF6sp RC/LB
2001 Chevy 2500HD 4x4 6.0/4L85E EC/SB
1997 Chevy Blazer 4x4
1994 Chevy K-2500 4x4 C6P 5.7/4L80E
1979 Chevy K-30 4x4 4sp 4.10
1977 Chevy K-30 4x4 4sp 4.10 454

Dad of an Eagle Scout, and a Life Scout

Offline heavychevy91

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Re: What Transmission and Tansfer Case do I have???
« Reply #7 on: March 16, 2012, 08:02:27 PM »
That's a 10-bolt F/A. No doubt about it.

Darn i posted too quick without looking. So should an 80 K20 have had a 44 and maybe someone swapped it out?

Offline Irish_Alley

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Re: What Transmission and Tansfer Case do I have???
« Reply #8 on: March 17, 2012, 02:06:30 AM »
i think 80 was the changing year where the early trucks got 44s while the new trucks got 10s
If you can’t tell yourself the truth, who can you tell it to?~Irish_Alley

When you have eliminated the impossible, whatever remains, however improbable, must be the truth ~Sherlock Holmes

Offline Engineer

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Re: What Transmission and Tansfer Case do I have???
« Reply #9 on: March 17, 2012, 05:24:25 PM »
If your '80 has a D44 then it was a swap.

Up to 1978, 1/2, 3/4 trucks had the D44. 1979~1987(91) had the 10-bolt.

Additionally, all 1980 4x4 trucks had the NP205, with spicer lockouts.
2002 Chevy 2500HD 4x4 8.1/ZF6sp RC/LB
2001 Chevy 2500HD 4x4 6.0/4L85E EC/SB
1997 Chevy Blazer 4x4
1994 Chevy K-2500 4x4 C6P 5.7/4L80E
1979 Chevy K-30 4x4 4sp 4.10
1977 Chevy K-30 4x4 4sp 4.10 454

Dad of an Eagle Scout, and a Life Scout

Offline Irish_Alley

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Re: What Transmission and Tansfer Case do I have???
« Reply #10 on: March 18, 2012, 01:44:09 AM »
lol i was off by a couple years but it could still be around in other stock setups
If you can’t tell yourself the truth, who can you tell it to?~Irish_Alley

When you have eliminated the impossible, whatever remains, however improbable, must be the truth ~Sherlock Holmes

Offline junkman.

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Re: What Transmission and Tansfer Case do I have???
« Reply #11 on: April 01, 2012, 04:02:45 PM »
Its a good drive train not the best or worst  we don't know what gear ratio you have but no problem using 33 inch tires and with 10 bolt front axle 36 inch max  if you run an open diff
maybe 38's  light foot

I have a friend that runs 38's with 1/2 tone axles and when it brakes he pays to have it fixed