Hydraulic vs. Mechanical clutch -- when did the change happen? - The 1947 - Present Chevrolet & GMC Truck Message Board Network

kipps · 01-11-2022, 04:10 PM

The debate keeps surfacing on Facebook from time to time. Was there a specific model year change in the clutch pedal design? Was it a running change that happened in the middle of a model year? Did some factories change before other factories did?

Hopefully Keith Seymour or someone else with factory experience can chime in here.

**kwmech** · 01-11-2022, 04:53 PM

1985

kipps · 01-11-2022, 10:39 PM

Quote:

Originally Posted by kwmech

1985

Some folks say they've seen hydraulic clutches as early as 1984 model year. Other folks declare up and down that their 1985 truck came with a mechanical clutch from the factory. Was there possibly some variation in the assembly plants?

**kwmech** · 01-12-2022, 01:55 AM

Possibly, from left over orders or inventory

Axle · 01-15-2022, 10:14 AM

How many different manual transmission where offered? Weight rating of the truck may also play into year difference disputes.

**kwmech** · 01-15-2022, 12:37 PM

Only 1 that I know of which was the SM465

kipps · 01-17-2022, 11:06 PM

Quote:

Originally Posted by kwmech

Only 1 that I know of which was the SM465

There were a couple others. There was a 833 transmission with four speeds, overdrive, a floor shifter, and was a side loader.

There was also at least one side-loader three-speed that was column shifted. I've never learned for sure if there was a second three-speed available or not.

**kwmech** · 01-18-2022, 10:26 AM

3 on the tree in 85?? never seen one of those

**hatzie** · 01-18-2022, 01:09 PM

I believe it was 1985. My 1985 C10 came with a hydraulic setup and I had a 1984 with the old Z-bar setup.
Can't forget what a pain in the neck it was to bleed the hydraulic clutch on that truck.

Mike C · 01-19-2022, 11:56 PM

I have an ‘83 crew with 4 speed that is mechanical and an ‘85 C20 and ‘85 C30 that are both hydraulic SM 465 setups. So after ‘83 and for sure by ‘85 but can’t speak to ‘84. Only one of those I’ve owned an auto.

**1957 Chief** · 01-21-2022, 05:04 PM

I have an 84, its a Z-bar like Hatzie mentioned.
Also have an 85 and 86, they are both hyd with the sm465 transmissions.

Bubba

**jlmerie** · 01-22-2022, 12:59 PM

I agree with the consensus. I got this out of a 1984 Blazer a few weeks ago. I do wish it had been an 85.

01-11-2022, 04:10 PM	#1
kipps Registered User Join Date: Jul 2014 Location: North-central Virginia Posts: 1,104	Hydraulic vs. Mechanical clutch -- when did the change happen? The debate keeps surfacing on Facebook from time to time. Was there a specific model year change in the clutch pedal design? Was it a running change that happened in the middle of a model year? Did some factories change before other factories did? Hopefully Keith Seymour or someone else with factory experience can chime in here. __________________ 1987 C6P V20 truck, 2010 LMG 5.3, AFM delete, 2010 Camaro exhaust manifolds, 1997 nv4500, 1991 np241c, hydroboost, 2005 14bff axle & driveshaft, drop-n-lock gooseneck, 4.10 gears, stock suspension, rims, and tires. Still a work in progress. Any questions or suggestions are welcome!

01-11-2022, 04:53 PM	#2
kwmech Senior Member Join Date: Mar 2003 Location: Colfax-California Posts: 8,649	Re: Hydraulic vs. Mechanical clutch -- when did the change happen? 1985

01-12-2022, 01:55 AM	#4
kwmech Senior Member Join Date: Mar 2003 Location: Colfax-California Posts: 8,649	Re: Hydraulic vs. Mechanical clutch -- when did the change happen? Possibly, from left over orders or inventory

01-15-2022, 10:14 AM	#5
Axle Registered User Join Date: Jul 2011 Location: SW Ontario Posts: 1,212	Re: Hydraulic vs. Mechanical clutch -- when did the change happen? How many different manual transmission where offered? Weight rating of the truck may also play into year difference disputes.

01-15-2022, 12:37 PM	#6
kwmech Senior Member Join Date: Mar 2003 Location: Colfax-California Posts: 8,649	Re: Hydraulic vs. Mechanical clutch -- when did the change happen? Only 1 that I know of which was the SM465

01-18-2022, 10:26 AM	#8
kwmech Senior Member Join Date: Mar 2003 Location: Colfax-California Posts: 8,649	Re: Hydraulic vs. Mechanical clutch -- when did the change happen? 3 on the tree in 85?? never seen one of those

01-18-2022, 01:09 PM	#9
hatzie Moderator Join Date: Oct 2008 Location: Wentworth, NH Posts: 4,977	Re: Hydraulic vs. Mechanical clutch -- when did the change happen? I believe it was 1985. My 1985 C10 came with a hydraulic setup and I had a 1984 with the old Z-bar setup. Can't forget what a pain in the neck it was to bleed the hydraulic clutch on that truck. __________________ 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.

01-19-2022, 11:56 PM	#10
Mike C Registered User Join Date: Dec 1999 Location: Austin, TX, USA Posts: 7,728	Re: Hydraulic vs. Mechanical clutch -- when did the change happen? I have an ‘83 crew with 4 speed that is mechanical and an ‘85 C20 and ‘85 C30 that are both hydraulic SM 465 setups. So after ‘83 and for sure by ‘85 but can’t speak to ‘84. Only one of those I’ve owned an auto. __________________ 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

01-21-2022, 05:04 PM	#11
1957 Chief Senior Member Join Date: Jun 2016 Location: Beebe, AR Posts: 462	Re: Hydraulic vs. Mechanical clutch -- when did the change happen? I have an 84, its a Z-bar like Hatzie mentioned. Also have an 85 and 86, they are both hyd with the sm465 transmissions. Bubba

01-22-2022, 12:59 PM	#12
jlmerie Registered User Join Date: Sep 2005 Location: Colorado Posts: 1,077	Re: Hydraulic vs. Mechanical clutch -- when did the change happen? I agree with the consensus. I got this out of a 1984 Blazer a few weeks ago. I do wish it had been an 85. Attached Images __________________ James



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