Transmission Help
Thread Starter
5th Gear
Joined: Jan 2024
Posts: 5
Likes: 1
From: New York
Transmission Help
Finally got my first corvette and transmission issue on my way home from dealer. Its a 04 base automatic transmission with 66k miles. Around town no issues but if I get on the highway for 15 to 30 min and then come to a stop I get a really hard slam from 1st to 2nd gear. Now if I restart the car the issue is gone. The only code i get is transmission slipping P0894. Any help or advice would be greatly appreciated.
Burning Brakes
Joined: Dec 2022
Posts: 1,033
Likes: 896
From: Nappytown MD
Fluid level? Fluid color? That would be my first thing I would look at. You could have low fluid and that hard shift could be the symptom of low fluid. There could be other issues as well but I would start there. And if it is low, then I would go back to that dealer and give them some "advice" and ask for a transmission service to make sure all is well.
I have a 02/A4 and the only time I ever felt that (hard shift from 1st to 2nd) is when I had the rear end swapped out to a 3.42 from the 2.73 stocker. I waited 2 months to have the ECU re-programmed since I was sending my car to be boosted and dyno tuned already scheduled. While I could drive the car if I went more than ~half throttle, the shifting was hard (like you describe) and I got the same code, but mine was due to the different physical rear gear ratio versus what was programmed so the speed tables were out of whack and I knew/expected that until I got the re-programming done.
I have a 02/A4 and the only time I ever felt that (hard shift from 1st to 2nd) is when I had the rear end swapped out to a 3.42 from the 2.73 stocker. I waited 2 months to have the ECU re-programmed since I was sending my car to be boosted and dyno tuned already scheduled. While I could drive the car if I went more than ~half throttle, the shifting was hard (like you describe) and I got the same code, but mine was due to the different physical rear gear ratio versus what was programmed so the speed tables were out of whack and I knew/expected that until I got the re-programming done.
Thread Starter
5th Gear
Joined: Jan 2024
Posts: 5
Likes: 1
From: New York
Fluid level? Fluid color? That would be my first thing I would look at. You could have low fluid and that hard shift could be the symptom of low fluid. There could be other issues as well but I would start there. And if it is low, then I would go back to that dealer and give them some "advice" and ask for a transmission service to make sure all is well.
I have a 02/A4 and the only time I ever felt that (hard shift from 1st to 2nd) is when I had the rear end swapped out to a 3.42 from the 2.73 stocker. I waited 2 months to have the ECU re-programmed since I was sending my car to be boosted and dyno tuned already scheduled. While I could drive the car if I went more than ~half throttle, the shifting was hard (like you describe) and I got the same code, but mine was due to the different physical rear gear ratio versus what was programmed so the speed tables were out of whack and I knew/expected that until I got the re-programming done.
I have a 02/A4 and the only time I ever felt that (hard shift from 1st to 2nd) is when I had the rear end swapped out to a 3.42 from the 2.73 stocker. I waited 2 months to have the ECU re-programmed since I was sending my car to be boosted and dyno tuned already scheduled. While I could drive the car if I went more than ~half throttle, the shifting was hard (like you describe) and I got the same code, but mine was due to the different physical rear gear ratio versus what was programmed so the speed tables were out of whack and I knew/expected that until I got the re-programming done.
Fluid looks great, level was perfect. As far as the dealer, they told me if they knew there was a problem they would not have sold it. "Good luck". So im on my own. The glove box option codes says it has the performance option 3.15 gears. I do remember when I under there checking the level that something was written on the diff cover in white maker. You maybe right. Gonna check it soon as i get off work.
Pro
Joined: Jul 2020
Posts: 549
Likes: 132
From: Texas
Fluid looks great, level was perfect. As far as the dealer, they told me if they knew there was a problem they would not have sold it. "Good luck". So im on my own. The glove box option codes says it has the performance option 3.15 gears. I do remember when I under there checking the level that something was written on the diff cover in white maker. You maybe right. Gonna check it soon as i get off work.
Safety Car
Joined: Jan 2012
Posts: 3,956
Likes: 520
From: Da U.P.
It sounds to me like you may have a torque converter lockup issue. That'll throw the slippage code, and ramp up line pressure and cause that harsh 1-2 shift. Of course there's other stuff that can too, but that particular issue comes with both of your observations.
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Instructor
Joined: Dec 2006
Posts: 153
Likes: 0
From: Southern CA
Check the transmission oil at proper temp?
Fluid looks great, level was perfect. As far as the dealer, they told me if they knew there was a problem they would not have sold it. "Good luck". So im on my own. The glove box option codes says it has the performance option 3.15 gears. I do remember when I under there checking the level that something was written on the diff cover in white maker. You maybe right. Gonna check it soon as i get off work.
Last edited by fun_n_sun; Jan 8, 2024 at 12:49 AM.
Race Director
Joined: Oct 2004
Posts: 12,864
Likes: 4,667
It may, or may not indicate your filter is plugged. However, given that you have an issue, and it improves somewhat if you shut it down, and gets better when you restart it, crap blocking the filter may drop away while the engine is off. Then, after restarting, it takes awhile before it plugs again. I'd stop driving it immediately!!! Drain the pan and remove it. There's supposed to be a strong magnet in the pan. If you don't see it, but there is a large clump of metallic fragments in one part of the pan, it's there. This usually means the Torque Converter Clutch has puked. The 4L60E is a decent trans, but it is the grandson of the 700R4. I had a 700R4 in an '85 IROC. The TCC clutch puked in that. It took out the entire transmission. It didn't want to shift from 1st to second, even at part throttle. Finally, at maybe 1/6th throttle at around 4,500rpm, it shifted. The rear tires really chirped as the car banged 2nd, and tried to fishtail!! A pan inspection should tell the tale.......
Burning Brakes
Joined: Mar 2014
Posts: 807
Likes: 239
Have you had the car tuned? I had a email ECS tune after headers and axle back install and it did the same as yours. Seems the tune was commanding full line pressure to the converter lockup when driving at highway speeds but didnt reduce it at slower speed so when I came to my first stop I got the hard 1-2 shift. Sent the ECM back and they reprogrammed it. Worked fine after that. Before the fix while driving on the highway I would pull codes and clear the fault. When I came to my forst stop the 1-2 shift was normal. Hope this helps.