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Discussion Starter #1
Hi everyone. Just picked up an 81 corvette. When I test drove it everything seemed great. I noticed it shifted nice and firm and i thought it had a nice shift kit in it. I bought it and had a 3 hour drive home. It drove great until i got off the highway. as i was going to slow down the tranny really "clunked" hard into the gears as I was coming to a stop. It felt like the tranny was gonna fall right out of the car. Got it in the drive and parked it for the day. The next day i drove it around and it seemed fine until it really warmed up and started to really shift hard. it has enough tranny fluid and seemes to get worse the hotter it gets. Any ideas or suggestions will be greatly valued.
 

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Firstly.. Welcome to DC.. :thumbsup:

Here are a few things I learned along the way..


  1. Heat is your Transmissions worst enemy. Try getting and installing a Tranny cooler (Costs about 60 bucks)
  2. Second, Check that the transmission mount is not broken and that the transmission is secure..
  3. I had the same problem with my tranny when I bought my car... When going from Drive to neutral or park and back the whole car was shaken by a THUD.. or THUNK !! A bit unnerving yes.. I had the Transmission rebuilt and also put in a shift kit. Now it is very smooth. Cost me about 900 bucks including labor, but it was worth it.
  4. Also check your U joints and rear end. The Thud that comes when you shift might be due to slack in any of these to your rear end.
  5. Luckily you are on DC. I have recieved the best , most sound advice from members here, who, I'm sure will chime in shortly.. :thumbsup:

PS: Here's how transmission cooler installation works.. It will help reduce heat and the damage it does to your tranny..

 

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Discussion Starter #3
Thanks for the welcome and response e tar. First off, I'm no mechanic, lol, so I need all the help I can get. When I start the car it goes in gear nice and firm but after it heats up it turns into bone jarring thuds. Its so hard I'm worried I will snap a u joint or rear end. I'm hoping its something cheap and easy to change with limited mechanical know-how. Lol. Someone said it might be a vacuum line????? No idea
 

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Thanks for the welcome and response e tar. First off, I'm no mechanic, lol, so I need all the help I can get. When I start the car it goes in gear nice and firm but after it heats up it turns into bone jarring thuds. Its so hard I'm worried I will snap a u joint or rear end. I'm hoping its something cheap and easy to change with limited mechanical know-how. Lol. Someone said it might be a vacuum line????? No idea
Are the exhaust pipes coming from the headers touching your transmission? Look underneath and let us know.. Heat seems to be a factor here..

If you are not technical, I would suggest you take it to a reputable transmission shop. Drive it there and back. Don't let them pick it up on a flatbed and take it for diagnosis.. I know many tranny shops offer this service, but then they have your car and they can milk you for work on it...

Drive it there and back. Select a shop that's close by..
They should be able to diagnose it. Or explain the symptoms to them over the phone and ask them what it could be..
 

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Well thanks for the advice E TAR. I drove the car to my local tranny shop for a free estimate. I figured they could at least tell me what was wrong. I wasn't even 100% sure it was the transmission, thought it could also be the rear end. Well it turned out to be both! The guy before me just put in a shift kit that was WAAAAYYY to big for the stock motor. After I drove the car for a three hour trip home the tranny really heated up and everything settled in. The shift kit was causing it to hit so hard that it wore out the u-joints in the rear end. The guys at the tranny shop put in a stock valve body and new u-joints and the car shifts fine. Thanks again for your help.
 
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