trans slipping/?? - The 1947 - Present Chevrolet & GMC Truck Message Board Network

jasonroman · 01-20-2011, 08:41 AM

well not sure if it is slipping or if problem is elsewhere.
from time to time, ill be driving at a steady speed. be it 40/45/55...either way, at a certain speed and maintaining that speed. and out of no where the truck revs up.
i know bad explination.
but when it does rev out of the norm, its quick. seconds.
for example if im doing 45 and if i had a tach, lets say it was at 3k at 45mph.
when the change comes about, i think i stay at 45 mph, but sounds as if rpms would go from 3k to 35-4k
agian, i know my explination is not too good. but thats what i notice happening.
not sure if its some sort of trans slippage or bad carb or what?

now reason id like to know problem is because i was recentley hit pulling into my driveway.
insurance only gave me 1800 to fix.
id like to take money and put into truck. but if i have a faulty trans or some major probs headed my way, i think i might look to buy another truck and put this one out back for slow but steady work.
thank for any kind of imput or suggestions

silvereagle07 · 01-20-2011, 11:01 AM

It could be slipping or the governor is sticking. I have seen this on a TH350 before. The next time it revs up "slips" put truck into neutral then back into drive. If the trans engages it's probally the governor. Good luck.

James McClure · 01-20-2011, 11:11 AM

Jason, What trans, what year? We need more info. Is fluid level ok and in good condition? Did it happen before you got hit? Could be several things from a minor detent or downshift cable issue (downshift switch\wireing on a 400) all the way up to major trans repair. jim

jasonroman · 01-20-2011, 11:55 AM

sorry to sound stupid here.
not sure trans.
not sure about fluid levels.
yes it did this prior to accident. got hit on the passenger side of bed.
damage is to bed side panel.
year is 1985
motor 5.7
trans maybe 700
square looking one.

mooseknuckles · 01-20-2011, 12:04 PM

check tranny fluid level,colour, and smell.

Keith Seymore · 01-20-2011, 04:30 PM

Do you have a fan clutch on the engine driven cooling fan?

You could be hearing the fan engaging and disengaging as it maintains engine cooling (sounds like an airplane going by) - which is pretty normal operation. Engine rpm might not actually be changing.

Can you install a tach temporarily to verify that the engine rpms are actually flaring up?

K

jasonroman · 01-20-2011, 10:25 PM

not sure about fan. but im pretty sure its not fan related.
ill look to see if i can find a cheap tach and figure out how to hook it up.

01-20-2011, 08:41 AM	#1
jasonroman Registered User Join Date: Jul 2008 Location: sayreville nj Posts: 1,072	trans slipping/?? well not sure if it is slipping or if problem is elsewhere. from time to time, ill be driving at a steady speed. be it 40/45/55...either way, at a certain speed and maintaining that speed. and out of no where the truck revs up. i know bad explination. but when it does rev out of the norm, its quick. seconds. for example if im doing 45 and if i had a tach, lets say it was at 3k at 45mph. when the change comes about, i think i stay at 45 mph, but sounds as if rpms would go from 3k to 35-4k agian, i know my explination is not too good. but thats what i notice happening. not sure if its some sort of trans slippage or bad carb or what? now reason id like to know problem is because i was recentley hit pulling into my driveway. insurance only gave me 1800 to fix. id like to take money and put into truck. but if i have a faulty trans or some major probs headed my way, i think i might look to buy another truck and put this one out back for slow but steady work. thank for any kind of imput or suggestions

01-20-2011, 11:01 AM	#2
silvereagle07 Registered User Join Date: Sep 2008 Location: Bailey, NC Posts: 2,462	Re: trans slipping/?? It could be slipping or the governor is sticking. I have seen this on a TH350 before. The next time it revs up "slips" put truck into neutral then back into drive. If the trans engages it's probally the governor. Good luck. __________________ Jeramy '84 GMC project truck '85 Chevy 4X4 SOLD '07 Chevy Trailblazer SS 5th Annual SHPHC Car/Truck Show Pics http://67-72chevytrucks.com/vboard/s...d.php?t=543605 UPDATED PICS! CHECK 'EM OUT

01-20-2011, 11:11 AM	#3
James McClure One shot, one kill. Join Date: Dec 2007 Location: Saratoga Springs NY Posts: 859	Re: trans slipping/?? Jason, What trans, what year? We need more info. Is fluid level ok and in good condition? Did it happen before you got hit? Could be several things from a minor detent or downshift cable issue (downshift switch\wireing on a 400) all the way up to major trans repair. jim __________________ 1984 K20 350M engine with 465,000 miles. Well, it's finally done!! Almost 2 years of work, but it was really worth the effort. Little stuff left to do is mount winch, wet sand & buff out and build belly pan\running boards. Body work takes lots and LOTS of beer!!!! God, Guts and Guns made America and God, Guts and Guns will preserve it! The worst thing you could do is get into my sights, but that don't matter, you'll never know it, cause you'll never hear the shotJim or Paladin whichever you choose.

01-20-2011, 11:55 AM	#4
jasonroman Registered User Join Date: Jul 2008 Location: sayreville nj Posts: 1,072	Re: trans slipping/?? sorry to sound stupid here. not sure trans. not sure about fluid levels. yes it did this prior to accident. got hit on the passenger side of bed. damage is to bed side panel. year is 1985 motor 5.7 trans maybe 700 square looking one.

01-20-2011, 12:04 PM	#5
mooseknuckles Registered User Join Date: Sep 2009 Location: ottawa,canada Posts: 4,550	Re: trans slipping/?? check tranny fluid level,colour, and smell. __________________ my build threads '86 C10 http://67-72chevytrucks.com/vboard/s...d.php?t=415628 '67 C10 http://67-72chevytrucks.com/vboard/s...d.php?t=635078 '63 GMC http://67-72chevytrucks.com/vboard/s...d.php?t=674682

01-20-2011, 04:30 PM	#6
Keith Seymore Registered User Join Date: May 2009 Location: Motor City Posts: 9,226	Re: trans slipping/?? Do you have a fan clutch on the engine driven cooling fan? You could be hearing the fan engaging and disengaging as it maintains engine cooling (sounds like an airplane going by) - which is pretty normal operation. Engine rpm might not actually be changing. Can you install a tach temporarily to verify that the engine rpms are actually flaring up? 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/ Last edited by Keith Seymore; 01-20-2011 at 04:31 PM.

01-20-2011, 10:25 PM	#7
jasonroman Registered User Join Date: Jul 2008 Location: sayreville nj Posts: 1,072	Re: trans slipping/?? not sure about fan. but im pretty sure its not fan related. ill look to see if i can find a cheap tach and figure out how to hook it up.



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