Need Advice Tunning My Truck In - The 1947 - Present Chevrolet & GMC Truck Message Board Network

Hair · 11-11-2012, 05:16 PM

71 GMC 250 Six with powerglide

Transmission would not shift into high gear. Pulled it out and took to transmission shop and had it rebuilt. In the mean time I also put an HEI unit in instead of points. The transmission shifts well now, and the engine runs fine, but here's my problem:

When it's in Drive or Reverse and sitting still with the brakes applied it runs very rough, not a miss, but like its lugging or trying to pull, it's feels like it needs a stall converter (but it don't, its all stock). If I idle it up high enough to run smoother I can REALLY feel it pulling then, like I'm trying to brake torque it and then it's "screaming" in Park.

I'm wondering about two things:
1.) I put Type "F" transmission fluid in it, hoping for a firmer shift.
Do you think that this could be my problem? Maybe someone has experienced this before? Should I drain/suck it ALL out as best I can and put Dexron III back in?

2.) I did not install a new torque converter.
Do you think that maybe the torque conveter could be bad? What does a bad torque converter in a power glide act like... never had a bad one.

Maybe something else?? Any advice appreciated. Thx

**LockDoc** · 11-11-2012, 05:57 PM

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Sounds like you may have a vacuum leak somewhere.

LockDoc

weever82 · 11-11-2012, 06:23 PM

Quote:

Originally Posted by LockDoc

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Sounds like you may have a vacuum leak somewhere.

LockDoc

+1, check the lines on the tranny when they put it back in.

Weev-
Posted via Mobile Device

PanelDeland · 11-11-2012, 09:32 PM

You put Ford type Tranny fluid in it.There is a difference.Dextron is for GM.

hayhauler71 · 11-11-2012, 10:21 PM

type f fluid is fine in that trans will not hurt the trans nor will not cause your problem.
Like said check for vac leak also check your timing and vac advance

11-11-2012, 05:16 PM	#1
Hair Registered User Join Date: Mar 2008 Location: Tullahoma, TN Posts: 406	Need Advice Tunning My Truck In 71 GMC 250 Six with powerglide Transmission would not shift into high gear. Pulled it out and took to transmission shop and had it rebuilt. In the mean time I also put an HEI unit in instead of points. The transmission shifts well now, and the engine runs fine, but here's my problem: When it's in Drive or Reverse and sitting still with the brakes applied it runs very rough, not a miss, but like its lugging or trying to pull, it's feels like it needs a stall converter (but it don't, its all stock). If I idle it up high enough to run smoother I can REALLY feel it pulling then, like I'm trying to brake torque it and then it's "screaming" in Park. I'm wondering about two things: 1.) I put Type "F" transmission fluid in it, hoping for a firmer shift. Do you think that this could be my problem? Maybe someone has experienced this before? Should I drain/suck it ALL out as best I can and put Dexron III back in? 2.) I did not install a new torque converter. Do you think that maybe the torque conveter could be bad? What does a bad torque converter in a power glide act like... never had a bad one. Maybe something else?? Any advice appreciated. Thx

11-11-2012, 05:57 PM	#2
LockDoc The Older Generation Join Date: Aug 2006 Location: Montezuma, Iowa Posts: 25,430	Re: Need Advice Tunning My Truck In - Sounds like you may have a vacuum leak somewhere. LockDoc __________________ Leon Locksmith, Specializing In Antique Trucks, Automobiles, & Motorcycles (My Dually Pickup Project Thread) http://67-72chevytrucks.com/vboard/s...d.php?t=829820 -

11-11-2012, 09:32 PM	#4
PanelDeland I am a Referee of life. Join Date: Jun 2000 Location: Greensboro N.C. Posts: 13,993	Re: Need Advice Tunning My Truck In You put Ford type Tranny fluid in it.There is a difference.Dextron is for GM. __________________ The 47-present Chevrolet and GMC Truck Message Board Network,it's owners,moderators,members,and associates of any type should not be held responsible for my opinion. You can't fix stupid,not even with duct tape. "My appearance is due to the fact that "GOD" does punish you for having too much fun!" Barrett-Jackson has perfected alchemy,they make rust into gold! "You can lead a horse to water but you can't saddle a duck" "Cleverly disguised as a 'Responsible Adult' "Sometimes your Knight in shining armor is just a retard in tinfoil"

11-11-2012, 10:21 PM	#5
hayhauler71 Registered User Join Date: Aug 2009 Location: St. Paul MN. Posts: 1,996	Re: Need Advice Tunning My Truck In type f fluid is fine in that trans will not hurt the trans nor will not cause your problem. Like said check for vac leak also check your timing and vac advance __________________ Fuzzy



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