The 1947 - Present Chevrolet & GMC Truck Message Board Network







Register or Log In To remove these advertisements.

Go Back   The 1947 - Present Chevrolet & GMC Truck Message Board Network > 47 - Current classic GM Trucks > The 1967 - 1972 Chevrolet & GMC Pickups Message Board

Web 67-72chevytrucks.com


Reply
 
Thread Tools Display Modes
Old 08-09-2018, 11:05 PM   #1
Tkrysl
Registered User
 
Join Date: Jul 2018
Location: FESTUS, MO
Posts: 22
Engine Revs Up but doesn't move truck any quicker

Total newbie to my truck but I'm learning everything I can.

72 C15 250inline.

Finally got her rolling and licensed! When I am driving down the road, she rides and drives great BUT when I get on the gas pedal good, the truck sounds as if it is revving up to take off but doesn't.

I'm assuming this isn't normal? Apologize in advance for ignorance!

Thanks,
Tkrysl is offline   Reply With Quote
Old 08-09-2018, 11:08 PM   #2
yuccales
Registered User
 
yuccales's Avatar
 
Join Date: May 2011
Location: Northern Calif.
Posts: 3,580
Re: Engine Revs Up but doesn't move truck any quicker

If manual trans, is your clutch slipping?
yuccales is offline   Reply With Quote
Old 08-09-2018, 11:10 PM   #3
Tkrysl
Registered User
 
Join Date: Jul 2018
Location: FESTUS, MO
Posts: 22
Re: Engine Revs Up but doesn't move truck any quicker

Sorry. It is a 3speed manual. I can't answer the question I guess because I wouldn't know what a clutch slip felt like?

Nothing seems out of the ordinary except the reving.
Tkrysl is offline   Reply With Quote
Old 08-09-2018, 11:14 PM   #4
truckster
Senior Member
 
truckster's Avatar
 
Join Date: Jan 2001
Location: Orem, Utah
Posts: 7,791
Re: Engine Revs Up but doesn't move truck any quicker

On a manual transmission the engine speed and the transmission output (vehicle speed) are directly related. If the engine revs and the speed doesn't increase it means your clutch is slipping. You may be able to adjust it if it's not too worn.
__________________
I have sworn upon the altar of God, eternal hostility against every form of tyranny over the mind of man. - Thomas Jefferson
truckster is online now   Reply With Quote
Old 08-09-2018, 11:16 PM   #5
LockDoc
The Older Generation

 
LockDoc's Avatar
 
Join Date: Aug 2006
Location: Montezuma, Iowa
Posts: 25,320
Re: Engine Revs Up but doesn't move truck any quicker

Quote:
Originally Posted by Tkrysl View Post
Sorry. It is a 3speed manual. I can't answer the question I guess because I wouldn't know what a clutch slip felt like?

Nothing seems out of the ordinary except the reving.
Clutch slipping is exactly what you are feeling. It may be adjustable, if not you will need a new clutch. Take it to a good mechanic and get his opinion....

LockDoc
__________________
Leon

Locksmith, Specializing In Antique Trucks, Automobiles, & Motorcycles

(My Dually Pickup Project Thread)

http://67-72chevytrucks.com/vboard/s...d.php?t=829820

-
LockDoc is offline   Reply With Quote
Old 08-09-2018, 11:18 PM   #6
Tkrysl
Registered User
 
Join Date: Jul 2018
Location: FESTUS, MO
Posts: 22
Re: Engine Revs Up but doesn't move truck any quicker

Gotcha. Assuming a clutch adjustment isn't for the shade tree mechanic?
Tkrysl is offline   Reply With Quote
Old 08-09-2018, 11:18 PM   #7
yuccales
Registered User
 
yuccales's Avatar
 
Join Date: May 2011
Location: Northern Calif.
Posts: 3,580
Re: Engine Revs Up but doesn't move truck any quicker

I don't have any pics of the clutch linkage and throwout fork to show you what to look for. Someone will help out soon. If you do a search for "clutch adjustment" that should head you in the right direction.
yuccales is offline   Reply With Quote
Old 08-10-2018, 01:00 AM   #8
Coley
Registered User
 
Coley's Avatar
 
Join Date: Oct 2011
Location: Victoria, B.C
Posts: 3,794
Smile Re: Engine Revs Up but doesn't move truck any quicker

If might be your clutch is slipping.
.....or did you buy a Ford by mistake?...recheck the registration.

all good
Coley
__________________
....for some men, there is experience, skill and effort....for the others...there is visa and UPS LOL
1966 Chevy 1/2 ton (Florida- Red/white)
1972 Chevy 1/2 ton (California- Blue/white)
2005 Chevy Silverado HD2500/Duramax
2000 Dodge Ram 1500
Coley is offline   Reply With Quote
Old 08-10-2018, 06:51 AM   #9
Grumpy old man
Senior Member
 
Grumpy old man's Avatar
 
Join Date: Dec 2013
Location: Gods country East,Tn
Posts: 8,545
Re: Engine Revs Up but doesn't move truck any quicker

Easy clutch check .

In a safe parking spot start your engine and set the emergency brake and keep your foot on the brake ,with the truck idling shift to 3rd gear and slowly release the clutch . If the truck continues to run you need clutch repair or replacement if the truck stalls you likely just need an adjustment
Grumpy old man is offline   Reply With Quote
Old 08-10-2018, 07:40 AM   #10
A1971Blazer
Senior Member
 
A1971Blazer's Avatar
 
Join Date: Nov 2013
Location: East Tennessee
Posts: 2,107
Re: Engine Revs Up but doesn't move truck any quicker

clutch adjustment is relatively easy....clutch replacement....not so much.
If you aren't too mechanically inclined...take it to a mechanic that you trust...
__________________
1967 C10 Step side
1968 C10 Step side
1970 Chevrolet K/5 Blazer
1972 Chevrolet K/5 Blazer
.............
A1971Blazer is online now   Reply With Quote
Old 08-10-2018, 08:10 AM   #11
special-K
Special Order

 
special-K's Avatar
 
Join Date: Nov 2004
Location: Mt Airy, MD
Posts: 85,862
Re: Engine Revs Up but doesn't move truck any quicker

I think Loc Doc suggested having it looked at by a shop because it sounds like you need someone more familiar with mechanical operations to evaluate. We are only guessing by what you describe. Also, a slipping clutch doesn't happen overnight. If that is what the problem is, we need to know how long it was slipping. The long it is allowed to slip the more damage done. The clutch surface could be glazed or worse, material worn away. Once the surface gets glazed you will not get proper clutch performance even after the simple process of adjusting the clutch.
__________________
"BUILDING A BETTER WAY TO SERVE THE USA"......67/72......"The New Breed"

GMC '67 C1500 Wideside Super Custom SWB: 327/M22/3.42 posi.........."The '67" (project)
GMC '72 K2500 Wideside Sierra Custom Camper: 350/TH350/4.10 Power-Lok..."The '72" (rolling)
Tim

"Don't call me a redneck. I'm a rough cut country gentleman"

R.I.P. ~ East Side Low Life ~ El Jay ~ 72BLUZ ~ Fasteddie69 ~ Ron586 ~ 67ChevyRedneck ~ Grumpy Old Man ~
special-K is offline   Reply With Quote
Old 08-10-2018, 09:00 AM   #12
Tkrysl
Registered User
 
Join Date: Jul 2018
Location: FESTUS, MO
Posts: 22
Re: Engine Revs Up but doesn't move truck any quicker

I'll get it up on the rack and have a look. It's at 64k but I just got it. Sat in a barn since 1993.
Tkrysl is offline   Reply With Quote
Old 08-10-2018, 09:21 AM   #13
bill3rail
Registered User
 
bill3rail's Avatar
 
Join Date: Jul 2013
Location: LI, NY 11801
Posts: 1,140
Re: Engine Revs Up but doesn't move truck any quicker

Where does the clutch grab when pushing the pedal down? Top or bottom?
If it grabs at the bottom, you may just need to adjust it to grab higher to get more engagement with the clutch. This is very simple to do and remember, a few turns makes a huge difference in the pedal.

Bill
__________________
1970 C10 8' Fleetside, L6 250, 3 on the Tree.
The most basic of pickup trucks!

Last edited by bill3rail; 08-11-2018 at 07:11 AM.
bill3rail is offline   Reply With Quote
Old 08-10-2018, 09:27 AM   #14
A1971Blazer
Senior Member
 
A1971Blazer's Avatar
 
Join Date: Nov 2013
Location: East Tennessee
Posts: 2,107
Re: Engine Revs Up but doesn't move truck any quicker

Quote:
Originally Posted by Tkrysl View Post
I'll get it up on the rack and have a look. It's at 64k but I just got it. Sat in a barn since 1993.
check the linkage to be sure it moves freely....sitting that long...it could be a bit sticky....have someone push the pedal down and watch the fork on the bellhousing to see if it's moving freely back and forth...
__________________
1967 C10 Step side
1968 C10 Step side
1970 Chevrolet K/5 Blazer
1972 Chevrolet K/5 Blazer
.............
A1971Blazer is online now   Reply With Quote
Old 08-10-2018, 12:04 PM   #15
special-K
Special Order

 
special-K's Avatar
 
Join Date: Nov 2004
Location: Mt Airy, MD
Posts: 85,862
Re: Engine Revs Up but doesn't move truck any quicker

Another possibility is the rear main is leaking from sitting and you have a wet clutch. You'll see the mess before going into it. Depends on how much it's been run since sitting. You have the inspection pan for visual inspection.
__________________
"BUILDING A BETTER WAY TO SERVE THE USA"......67/72......"The New Breed"

GMC '67 C1500 Wideside Super Custom SWB: 327/M22/3.42 posi.........."The '67" (project)
GMC '72 K2500 Wideside Sierra Custom Camper: 350/TH350/4.10 Power-Lok..."The '72" (rolling)
Tim

"Don't call me a redneck. I'm a rough cut country gentleman"

R.I.P. ~ East Side Low Life ~ El Jay ~ 72BLUZ ~ Fasteddie69 ~ Ron586 ~ 67ChevyRedneck ~ Grumpy Old Man ~
special-K is offline   Reply With Quote
Old 08-11-2018, 02:18 AM   #16
mike16
Registered User
 
Join Date: Dec 2009
Location: bisbee, arizona
Posts: 1,529
Re: Engine Revs Up but doesn't move truck any quicker

I remember when Motor Trend did a report on a 72 vega with an automatic. They also said that when you stepped on the gas to accelerate it made more noise but didn't move any faster. I drove one for 3 years and that is very much the truth.

but when a clutch slips there is also an unmistakable smell. like very hot brakes. dead give away. If the cause is related to oil on the disc, then you will smell hot brakes smell and burning oil smell too.

dont play around with it too much or you could ruin the flywheel too.
mike16 is offline   Reply With Quote
Old 08-11-2018, 10:31 AM   #17
Tkrysl
Registered User
 
Join Date: Jul 2018
Location: FESTUS, MO
Posts: 22
Re: Engine Revs Up but doesn't move truck any quicker

Quote:
Originally Posted by mike16 View Post
I remember when Motor Trend did a report on a 72 vega with an automatic. They also said that when you stepped on the gas to accelerate it made more noise but didn't move any faster. I drove one for 3 years and that is very much the truth.

but when a clutch slips there is also an unmistakable smell. like very hot brakes. dead give away. If the cause is related to oil on the disc, then you will smell hot brakes smell and burning oil smell too.

dont play around with it too much or you could ruin the flywheel too.
I don't smell anything. Here is a picture of what I believe is the adjustment rod. My manual doesn't say to tighten or loosen. Any advice?
Tkrysl is offline   Reply With Quote
Old 08-11-2018, 04:04 PM   #18
Tkrysl
Registered User
 
Join Date: Jul 2018
Location: FESTUS, MO
Posts: 22
Re: Engine Revs Up but doesn't move truck any quicker

Sorry. Here's the pic.
Attached Images
 
Tkrysl is offline   Reply With Quote
Old 08-11-2018, 04:05 PM   #19
Tkrysl
Registered User
 
Join Date: Jul 2018
Location: FESTUS, MO
Posts: 22
Re: Engine Revs Up but doesn't move truck any quicker

Quote:
Originally Posted by Grumpy old man View Post
Easy clutch check .

In a safe parking spot start your engine and set the emergency brake and keep your foot on the brake ,with the truck idling shift to 3rd gear and slowly release the clutch . If the truck continues to run you need clutch repair or replacement if the truck stalls you likely just need an adjustment
Ok thanks. It died.
Tkrysl is offline   Reply With Quote
Reply

Bookmarks


Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump


All times are GMT -4. The time now is 02:30 PM.


Powered by vBulletin® Version 3.8.11
Copyright ©2000 - 2024, vBulletin Solutions Inc.
Copyright 1997-2022 67-72chevytrucks.com