trans prob or not? please help

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Dec 26, 2006 | 07:31 PM

74vette454

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From: Orlando Florida

trans prob or not? please help

I have a 74 with a 454 when i hit the gas at about 50 the the tranny will downshift (auto). my tach doesnt work so I dont know at what rpm it shifts at but when I floor it until I hit 80 the trans will slam into the final gear and spin the tires for about 1 second... does this seem right? the car from what im told is stock the rear end is a 3.08... it does have headers on it and it sounds at an idle like it has a small cam even though the owner told me the engine and trans were just rebuilt (stock)? Does this seem right for a car with around 300 hp? at 80 with one person in the car it chirps the tires???? when driving normal the trans does not shift like this... it shifts nice and smooth... but when you floor it.. it slams into gear like power shifting a manual???? (first automatic sports car)????

Dec 26, 2006 | 07:38 PM

63mako

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From: Millington Illinois

St. Jude Donor '08-'09

Quote:

Originally Posted by 74vette454

No problem! Sound just like what you want it to do!

Dec 26, 2006 | 08:49 PM

74vette454

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From: Orlando Florida

so are you saying that a 74 vette should be able to spin the tires at 80? or are you saying that they must have done some mods ie shift kit or engine mods or both to the car????

Dec 26, 2006 | 09:02 PM

63mako

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From: Millington Illinois

St. Jude Donor '08-'09

Quote:

Originally Posted by 74vette454

so are you saying that a 74 vette should be able to spin the tires at 80? or are you saying that they must have done some mods ie shift kit or engine mods or both to the car????

Yes. A properly tuned 454 with headers, a small cam and stock sized tires should break them lose a little on the 2 to 3 shift at 80with your foot in it. Could have a shift kit, hard to say from here.

Sound like a nice ride!

Last edited by 63mako; Dec 26, 2006 at 09:04 PM.

Dec 26, 2006 | 10:41 PM

7T1vette

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From: Crossville TN

A lot of folks who have only driven Corvettes with manual transmissions think that automatics are for "sissies". Actually, the THM 400 is one of the best, strongest and best shifting automatics ever made. Some of the fastest strip cars have TMH 400's (some modified...some not). To have a lot of fun, put the shift lever in low range, stomp on it...and leave it there until it shifts to 2nd range on it's own. There is a low range shift inhibitor built in so it can't overrev....but, it's a hoot when it shifts. If you are chirping at 80mph [going into 3rd], you'll fishtail the he&& out of it when it slams into second. Oh, with a 454 & cam, you'd better have good quality, solid U-joints (no zerks) for that shift or you could throw a half-shaft or two.

Dec 26, 2006 | 10:49 PM

ETM

Melting Slicks

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From: Folsom Ca

I wish I had that problem.

Dec 26, 2006 | 10:56 PM

Pusher

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From: Arizona

Dec 27, 2006 | 05:48 PM

74vette454

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From: Orlando Florida

thanks for the info... i had better replace the u joints all around.. I think they are pretty old the left side clicks a little while taking a slow corner... I wouldnt want to brake an axle loose... as for driving with a manual.. ive always been one to like a sports car in a manual.. but the older cars like this i prefer the automatic because i drove a few of the manuals and its just not as smooth and quick as the newer cars...