78 Step Side 6 cylinder 4 speed - The 1947 - Present Chevrolet & GMC Truck Message Board Network

novapwr · 08-17-2012, 10:14 PM

Hey guys and gals. Just acquired this old 78 4x4 step side with the six cylinder truck, pretty solid but transfer case and tranny look to be both leaking lube pretty good. The guy I bought it from only used it to plow with then it sat. Can you tell me the model transfer case I have and tranny? The transfer case has low and hi range and the tranny has the granny gear. Both are very quiet and work great. How hard is it to replace the seals on these. Tranny looks pretty heavy. Am I looking at a very expensive repair if only seals are bad? Pretty sure they would need removed. I did do a search but did not find the info I needed. Thanks .

**hatzie** · 08-19-2012, 01:24 PM

SM465 Transmission. Really a 3 speed with low gear. Heavier than a dead horse. Plowing with a manual transmission is rough on the clutch.

Check the front axle for manual locking hubs. If it has them then you prolly have an NP205 or a part-time converted NP203.

The NP203 is a massive chain drive transfer case and probably heavier than the transmission. It's full time 4x4 with a range box and a diff.
Stock NP203 shift pattern.

Lo-Loc (Low range, center diff locked)
Lo (Low range, center diff unlocked)
N (No drive to axles)
Hi (Hi range, center diff unlocked)
Hi-Loc (Hi range, center diff locked)

Converted NP203 shift pattern

Lo-Loc (Low range, 4x4)
Lo (Low range, 2wd)
N (No drive to axles)
Hi (Hi range, 2wd)
Hi-Loc (Hi range, 4x4)

The NP205 is part time and gear drive. It's slightly smaller than the NP203 but is still cast iron and full of gears... very heavy.
NP205 Shift pattern

4LO (Low range 4wd)
N (No drive to axles)
2HI (2WD no drive to front)
4HI (High range 4wd)

novapwr · 08-19-2012, 05:13 PM

Quote:

Originally Posted by hatzie

SM465 Transmission. Really a 3 speed with low gear. Heavier than a dead horse. Plowing with a manual transmission is rough on the clutch.

Check the front axle for manual locking hubs. If it has them then you prolly have an NP205 or a part-time converted NP203.

The NP203 is a massive chain drive transfer case and probably heavier than the transmission. It's full time 4x4 with a range box and a diff.
Stock NP203 shift pattern.

Lo-Loc (Low range, center diff locked)
Lo (Low range, center diff unlocked)
N (No drive to axles)
Hi (Hi range, center diff unlocked)
Hi-Loc (Hi range, center diff locked)

Converted NP203 shift pattern

Lo-Loc (Low range, 4x4)
Lo (Low range, 2wd)
N (No drive to axles)
Hi (Hi range, 2wd)
Hi-Loc (Hi range, 4x4)

The NP205 is part time and gear drive. It's slightly smaller than the NP203 but is still cast iron and full of gears... very heavy.
NP205 Shift pattern

4LO (Low range 4wd)
N (No drive to axles)
2HI (2WD no drive to front)
4HI (High range 4wd)

Thank you for the info. I think I will have someone do this for me. I have no lift and they sure do look really heavy.

cory d · 08-19-2012, 05:24 PM

they are, its a giant chunk of iron, i didnt even try to pick mine up when i swapped it in

novapwr · 08-19-2012, 07:02 PM

Quote:

Originally Posted by cory d

they are, its a giant chunk of iron, i didnt even try to pick mine up when i swapped it in

Lol! Well then I dont feel so bad having someone else do it. Sounds like it will be money well spent!

**hatzie** · 08-19-2012, 08:07 PM

Don't be scared of it unless you don't have a concrete pad/floor to do it on. It's no heavier than an automatic transmission and transfer case just smaller.
Transmission jacks are $150-$200.

novapwr · 08-21-2012, 07:51 AM

Quote:

Originally Posted by hatzie

Don't be scared of it unless you don't have a concrete pad/floor to do it on. It's no heavier than an automatic transmission and transfer case just smaller.
Transmission jacks are $150-$200.

Well I stopped by the tranny shop and he said it looked to him like just the transfer case leaking and he or I could replace the seals without dropping anything. But I will be watching for a transmission jack now that I looked at them. Save a guy a lot of grief wrestling those things in and out. Thanks for all the help.

novapwr · 09-09-2012, 09:45 PM

Well I took some advice from here and changed out the front transfer case seal myself yesterday. Did a good pressure washing under there first. Wasn't as bad as I thought and the leak is gone! Just wanted to thank those who gave me advice and some answers. Appreciated. Now on to adjusting that one barrel carb...lol.

Keith Seymore · 09-10-2012, 06:56 AM

Good job!

Sounds like you learned something and maybe saved a few bucks in the process.

K

08-17-2012, 10:14 PM	#1
novapwr Registered User Join Date: Feb 2009 Location: Morrisdale, PA Posts: 9	78 Step Side 6 cylinder 4 speed Hey guys and gals. Just acquired this old 78 4x4 step side with the six cylinder truck, pretty solid but transfer case and tranny look to be both leaking lube pretty good. The guy I bought it from only used it to plow with then it sat. Can you tell me the model transfer case I have and tranny? The transfer case has low and hi range and the tranny has the granny gear. Both are very quiet and work great. How hard is it to replace the seals on these. Tranny looks pretty heavy. Am I looking at a very expensive repair if only seals are bad? Pretty sure they would need removed. I did do a search but did not find the info I needed. Thanks .

08-19-2012, 01:24 PM	#2
hatzie Moderator Join Date: Oct 2008 Location: Wentworth, NH Posts: 4,932	Re: 78 Step Side 6 cylinder 4 speed SM465 Transmission. Really a 3 speed with low gear. Heavier than a dead horse. Plowing with a manual transmission is rough on the clutch. Check the front axle for manual locking hubs. If it has them then you prolly have an NP205 or a part-time converted NP203. The NP203 is a massive chain drive transfer case and probably heavier than the transmission. It's full time 4x4 with a range box and a diff. Stock NP203 shift pattern. Lo-Loc (Low range, center diff locked) Lo (Low range, center diff unlocked) N (No drive to axles) Hi (Hi range, center diff unlocked) Hi-Loc (Hi range, center diff locked) Converted NP203 shift pattern Lo-Loc (Low range, 4x4) Lo (Low range, 2wd) N (No drive to axles) Hi (Hi range, 2wd) Hi-Loc (Hi range, 4x4) The NP205 is part time and gear drive. It's slightly smaller than the NP203 but is still cast iron and full of gears... very heavy. NP205 Shift pattern 4LO (Low range 4wd) N (No drive to axles) 2HI (2WD no drive to front) 4HI (High range 4wd) __________________ 1959 M35A2 LDT465-1D SOLD 1967 Dodge W200 B383, NP420/NP201 SOLD 1969 Dodge Polara 500 B383, A833 SOLD 1972 Ford F250 FE390, NP435/NP205 SOLD 1976 Chevy K20, 6.5L, NV4500/NP208 SOLD 1986 M1008 CUCV SOLD 2000 GMC C2500, TD6.5L, NV4500 2005 Chevy Silverado LS 2500HD 6.0L 4L80E/NP263 2009 Impala SS LS4 V8 RTFM... GM Parts Books, GM Schematics, GM service manuals, and GM training materials... 1973-1991 GM Light Truck Service, Unit/Overhaul, Wiring Manuals, Parts Books and Some 1968-1999 GM Service Training textbooks in PDF 1988-1998 GMT400 CK service manual project 1988-1993 GMT400 CK parts books. 1967-1972 GM Light, Medium, & Heavy Truck Service Manuals in PDF Please include at least the year and model in your threads. It'll be easier to answer your questions. And please let us know if and how your repairs were successful.

08-19-2012, 05:24 PM	#4
cory d Registered User Join Date: Dec 2011 Location: Arlington WA Posts: 1,728	Re: 78 Step Side 6 cylinder 4 speed they are, its a giant chunk of iron, i didnt even try to pick mine up when i swapped it in __________________ GMC C15 355 SM465 3.73 80 C10 cruiser build thread 79 short stepside crew cab. big and ugly. build thread

08-19-2012, 08:07 PM	#6
hatzie Moderator Join Date: Oct 2008 Location: Wentworth, NH Posts: 4,932	Re: 78 Step Side 6 cylinder 4 speed Don't be scared of it unless you don't have a concrete pad/floor to do it on. It's no heavier than an automatic transmission and transfer case just smaller. Transmission jacks are $150-$200. __________________ 1959 M35A2 LDT465-1D SOLD 1967 Dodge W200 B383, NP420/NP201 SOLD 1969 Dodge Polara 500 B383, A833 SOLD 1972 Ford F250 FE390, NP435/NP205 SOLD 1976 Chevy K20, 6.5L, NV4500/NP208 SOLD 1986 M1008 CUCV SOLD 2000 GMC C2500, TD6.5L, NV4500 2005 Chevy Silverado LS 2500HD 6.0L 4L80E/NP263 2009 Impala SS LS4 V8 RTFM... GM Parts Books, GM Schematics, GM service manuals, and GM training materials... 1973-1991 GM Light Truck Service, Unit/Overhaul, Wiring Manuals, Parts Books and Some 1968-1999 GM Service Training textbooks in PDF 1988-1998 GMT400 CK service manual project 1988-1993 GMT400 CK parts books. 1967-1972 GM Light, Medium, & Heavy Truck Service Manuals in PDF Please include at least the year and model in your threads. It'll be easier to answer your questions. And please let us know if and how your repairs were successful.

09-09-2012, 09:45 PM	#8
novapwr Registered User Join Date: Feb 2009 Location: Morrisdale, PA Posts: 9	Re: 78 Step Side 6 cylinder 4 speed Well I took some advice from here and changed out the front transfer case seal myself yesterday. Did a good pressure washing under there first. Wasn't as bad as I thought and the leak is gone! Just wanted to thank those who gave me advice and some answers. Appreciated. Now on to adjusting that one barrel carb...lol.

09-10-2012, 06:56 AM	#9
Keith Seymore Registered User Join Date: May 2009 Location: Motor City Posts: 9,177	Re: 78 Step Side 6 cylinder 4 speed Good job! Sounds like you learned something and maybe saved a few bucks in the process. K __________________ Chevrolet Flint Assembly 1979-1986 GM Full Size Truck Engineering 1986 - 2019 Intro from an Old Assembly Guy: http://67-72chevytrucks.com/vboard/s...d.php?t=342926 My Pontiac story: http://forums.maxperformanceinc.com/...d.php?t=560524 Chevelle intro: http://www.superchevy.com/features/s...hevy-chevelle/



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