4 speed transmission help - The 1947 - Present Chevrolet & GMC Truck Message Board Network

**burb71** · 01-21-2020, 07:14 AM

I recently acquired another truck, this one is a 1968, C/20 Custom Camper, 327, 4 speed.
Reverse doesn't work, does anyone have any idea what the likely problem could be ?
Also where can I buy a rebuild kit for an original 68, 4 speed?

Astro-Balls · 01-21-2020, 08:17 AM

What transmission do you have?

**burb71** · 01-21-2020, 11:49 AM

I don't know how to tell what 4-speed I have, can you tell me an easy way to find out?

palallin · 01-21-2020, 12:01 PM

What is the shift pattern?

**Sheepdip** · 01-21-2020, 12:05 PM

Should be a SM 465

https://upload.wikimedia.org/wikiped...ransmition.jpg

It's predecessor was the SM 420

http://www.novak-adapt.com/images/pi...21_adapter.jpg

**A1971Blazer** · 01-21-2020, 12:06 PM

www.torqueking4x4.com
has parts for manual transmissions
you could have a SM420...NP435...or SM465 in that year
https://torqueking.com/category/1967...transmissions/

**kwmech** · 01-21-2020, 12:22 PM

PTO cover on drivers side only---420
PTO cover on both sides---465
PTO cover on pass side only---435...........the 435 also has an aluminum top shifter tower

projectking · 01-21-2020, 03:18 PM

If you have a 435 would you please tell me which frame holes the frame stands are in and post a pic of your high hump transmission cover?

Willys_MB · 01-21-2020, 04:14 PM

Quote:

Originally Posted by projectking

If you have a 435 would you please tell me which frame holes the frame stands are in and post a pic of your high hump transmission cover?

I saw your post a while back, but didn't realize you didn't get the answer. I'll take a look tonight and get you some pics if the wifey/kiddos let me

projectking · 01-21-2020, 04:21 PM

Quote:

Originally Posted by Willys_MB

I saw your post a while back, but didn't realize you didn't get the answer. I'll take a look tonight and get you some pics if the wifey/kiddos let me

Thanks, I got close...his is a big block though

**burb71** · 01-21-2020, 07:06 PM

Here's a picture of the shift pattern along with the shifters position on the high hump.
Also it does have an inspection cover on both driver and passenger side, passenger side shown in picture.

Willys_MB · 01-22-2020, 12:36 PM

Quote:

Originally Posted by projectking

Thanks, I got close...his is a big block though

I posted my pics in your other thread to help keep this one relevant to the OP.

projectking · 01-21-2020, 07:26 PM

I’d say it’s a 465. The date code is what you cleaned off 3/19/6x the GM number is below it

Mike C · 01-21-2020, 08:35 PM

I agree, SM465. The NP would not say GM on it. The NP435 and SM465 have same shift pattern with reverse down and to the right. The SM420 has reverse down and to the LEFT.

**burb71** · 01-21-2020, 09:39 PM

Okay thanks guys that date code the last digit is "8 " it's a 68

projectking · 01-21-2020, 09:51 PM

Quote:

Originally Posted by burb71

Okay thanks guys that date code the last digit is "8 " it's a 68

Your welcome!

01-21-2020, 07:14 AM	#1
burb71 Active Member Join Date: Oct 2002 Location: Ft. Myers, Fl Posts: 1,716	4 speed transmission help I recently acquired another truck, this one is a 1968, C/20 Custom Camper, 327, 4 speed. Reverse doesn't work, does anyone have any idea what the likely problem could be ? Also where can I buy a rebuild kit for an original 68, 4 speed?

01-21-2020, 08:17 AM	#2
Astro-Balls Registered User Join Date: Feb 2019 Location: Nor Cal Posts: 822	Re: 4 speed transmission help What transmission do you have? __________________ 1968 C20 Fleetside 396 4sp PS PB AC CST . https://www.youtube.com/watch?v=RWK8GgWD4uA

01-21-2020, 11:49 AM	#3
burb71 Active Member Join Date: Oct 2002 Location: Ft. Myers, Fl Posts: 1,716	Re: 4 speed transmission help I don't know how to tell what 4-speed I have, can you tell me an easy way to find out?

01-21-2020, 12:01 PM	#4
palallin Registered User Join Date: Jul 2002 Location: St. James, MO Posts: 1,238	Re: 4 speed transmission help What is the shift pattern? __________________ '69 Longstep K-10: 327/SM465/T-221/Closed Knuckle Dana44/12-bolt.

01-21-2020, 12:05 PM	#5
Sheepdip Senior Member Join Date: Nov 2018 Location: Waterford California Posts: 2,587	Re: 4 speed transmission help Should be a SM 465 https://upload.wikimedia.org/wikiped...ransmition.jpg It's predecessor was the SM 420 http://www.novak-adapt.com/images/pi...21_adapter.jpg

01-21-2020, 12:06 PM	#6
A1971Blazer Senior Member Join Date: Nov 2013 Location: East Tennessee Posts: 2,185	Re: 4 speed transmission help www.torqueking4x4.com has parts for manual transmissions you could have a SM420...NP435...or SM465 in that year https://torqueking.com/category/1967...transmissions/ __________________ 1967 C10 Step side 1968 C10 Step side 1970 Chevrolet K/5 Blazer 1972 Chevrolet K/5 Blazer .............

01-21-2020, 12:22 PM	#7
kwmech Senior Member Join Date: Mar 2003 Location: Colfax-California Posts: 8,595	Re: 4 speed transmission help PTO cover on drivers side only---420 PTO cover on both sides---465 PTO cover on pass side only---435...........the 435 also has an aluminum top shifter tower

01-21-2020, 03:18 PM	#8
projectking Registered User Join Date: Oct 2006 Location: Orland Park Il Posts: 2,041	Re: 4 speed transmission help If you have a 435 would you please tell me which frame holes the frame stands are in and post a pic of your high hump transmission cover? __________________ 68 GMC C3500 Longhorn DRW 67 Chevy C10 LWB 90 Mustang Gt 90 Mustang Notchback

01-21-2020, 07:06 PM	#11
burb71 Active Member Join Date: Oct 2002 Location: Ft. Myers, Fl Posts: 1,716	Re: 4 speed transmission help Here's a picture of the shift pattern along with the shifters position on the high hump. Also it does have an inspection cover on both driver and passenger side, passenger side shown in picture. Attached Images

01-21-2020, 07:26 PM	#13
projectking Registered User Join Date: Oct 2006 Location: Orland Park Il Posts: 2,041	Re: 4 speed transmission help I’d say it’s a 465. The date code is what you cleaned off 3/19/6x the GM number is below it __________________ 68 GMC C3500 Longhorn DRW 67 Chevy C10 LWB 90 Mustang Gt 90 Mustang Notchback

01-21-2020, 08:35 PM	#14
Mike C Registered User Join Date: Dec 1999 Location: Austin, TX, USA Posts: 7,723	Re: 4 speed transmission help I agree, SM465. The NP would not say GM on it. The NP435 and SM465 have same shift pattern with reverse down and to the right. The SM420 has reverse down and to the LEFT. __________________ 44 Willys MB 52 M38A1 64 Corvette Coupe 68 Camaro 'vert LT1 & TH700 69 Z/28 355 12.6's @110 69 Chevy Short Step 4 1/2"/7" drop 72 Jimmy 4WD 4spd 4" & 35's 02 GMC 2500HD 4x4 Duramax

01-21-2020, 09:39 PM	#15
burb71 Active Member Join Date: Oct 2002 Location: Ft. Myers, Fl Posts: 1,716	Re: 4 speed transmission help Okay thanks guys that date code the last digit is "8 " it's a 68

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