No 4th gear.
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Race Director
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From: Sunshine Coast, Queensland, Australia
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No 4th gear.
I have a 84, Box stock. With a 700R4 Auto trans. Just changed the pan gasket and filter. Topped it up with new fluid, ran the car and put in into reverse and drive a few times. Held it in drive while running, Checked the fluid level and topped it up a bit. Drove the car and it wont shift into fourth gear. Checked the vacuum line at the back of the manifold. It is hooked up. There is a "T" with a filter just about an inch behind the manifold fitting, the line that go's off to the cruise control and vacuum tank was squished shut, however the hard plastic line heading down to the trans looks fine. This is all I know at this time, And yes it shifted fine before the fluid and filter change. Any Ideas as to what to look for?
Race Director
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I have a 84, Box stock. With a 700R4 Auto trans. Just changed the pan gasket and filter. Topped it up with new fluid, ran the car and put in into reverse and drive a few times. Held it in drive while running, Checked the fluid level and topped it up a bit. Drove the car and it wont shift into fourth gear. Checked the vacuum line at the back of the manifold. It is hooked up. There is a "T" with a filter just about an inch behind the manifold fitting, the line that go's off to the cruise control and vacuum tank was squished shut, however the hard plastic line heading down to the trans looks fine. This is all I know at this time, And yes it shifted fine before the fluid and filter change. Any Ideas as to what to look for?
No 4th upshift is odd.
Is it shifting from 3rd to 4th and 4th is acting like neutral?
Or is it simply staying in 3rd and not attempting to upshift?
Did you use sealant such as silicone on the pan gasket?
If yes, you likely plugged the servo dump hole in the pan rail.
Thread Starter
Race Director
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From: Sunshine Coast, Queensland, Australia
2025 C3 of the Year Finalist - Modified
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Yes I did use silicone on the pan gasket. There is a "Dump" hole in the pan gasket surface?. If so I did not see it. It is simply staying in 3rd, no 3-4 up-shift.
Le Mans Master
Joined: May 2005
Posts: 5,214
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From: Queensland, AUSTRALIA
No vacuum line goes to the trans on them mate. The lines from that T fitting go to the cruise and the other goes to the dash A/C vent control. That filter isnt a filter, its a one way valve.
What was the coolant temp up to? are you sure its not going into 4th and its un noticed cause the TCC isnt locked?
What was the coolant temp up to? are you sure its not going into 4th and its un noticed cause the TCC isnt locked?
Race Director
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Never use sealant on a trans gasket, for this reason. Vaseline is what I normally use.
If you are lucky, a small amout of trash was stirred up and the 3-4 upshift valve is sticking. I am heading out to work now, but will investigate it a bit when I return.
Thread Starter
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From: Sunshine Coast, Queensland, Australia
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Casey lives! Haven't heard from ya in a while, Yes I am sure it's not shifting up. Tach tells the whole story. I drove the wife's car for the first time last night to a small car show and it wasn't shifting into 4th. When I talked to the Her about it, I got the standard answer, "I thought it wasn't". However she never said anything prior. No It is not up-shifting. Also I put sealer on the gasket as I had no choice. Vendor had folded it in 4 to make it smaller for shipping. I have a new non-folded gasket. I can pull the pan and change, but why no 4th gear? Anything else I can look for when I have it apart? I hate to take it in to a auto-trans guy as the family budget cant handle it right now.
Le Mans Master
Joined: May 2005
Posts: 5,214
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From: Queensland, AUSTRALIA
Yeah mate, ive been quite busy of late, been doing the maintenance man job at work instead of the kitchen. Heaps better job!! The amount of things ive fixed that id never pulled apart or even looked at before (i had to even make a tool to fix a part from a 3 foot stick blender) Been having a great time.
That is pretty insane of the vendor to fold a cork gasket!!! Im shocked he/she would be so stupid.
I spose while the pan is off check and see that the valve body is tight, check that the shifter cable is set correctly, and make sure there is no blockages you can see anywhere.
If you have the old filter, get it and open it up if you havent done so, it can tell alot about the internals
Here is a pic of mine out of the 94 before i rebuilt it, full of clutches (and you might even be able to make out a couple little sparkles of the metal where one of the gears was losing the hard facing). Hard to see, but if you save the pic on your computer then blow it up abit youll be able to see more
That is pretty insane of the vendor to fold a cork gasket!!! Im shocked he/she would be so stupid.
I spose while the pan is off check and see that the valve body is tight, check that the shifter cable is set correctly, and make sure there is no blockages you can see anywhere.
If you have the old filter, get it and open it up if you havent done so, it can tell alot about the internals
Here is a pic of mine out of the 94 before i rebuilt it, full of clutches (and you might even be able to make out a couple little sparkles of the metal where one of the gears was losing the hard facing). Hard to see, but if you save the pic on your computer then blow it up abit youll be able to see more
Last edited by Casethecorvetteman; May 11, 2007 at 10:29 AM.
Thread Starter
Race Director
Joined: Nov 2006
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From: Sunshine Coast, Queensland, Australia
2025 C3 of the Year Finalist - Modified
2024 C3 of the Year Finalist- Modified
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I am sure I dont have the old filter anymore. I am also not very knowlageable on auto tranys. If the 3-4 up-shift valve thing has junk in it were do I find it? Photo's anyone?
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Racer
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From: Anniston BAMA
I was scopin out corvette action center for some info on my shifter and ran across a couple of articles regarding recall fixes on the no 4th gear scenario. look in the knowledgebase under clutch and transmission. hope it helps.
Le Mans Master
Joined: May 2005
Posts: 5,214
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From: Queensland, AUSTRALIA
Im not sure where that item is mate, do you have a GM service manual for either of the 2 C4s youve got there? If you do it should have a full tear down in it, and will also have quite a few pages of trouble shooting. Ive got one here, but i wont be able to get to it til probably tomorrow.
Thread Starter
Race Director
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From: Sunshine Coast, Queensland, Australia
2025 C3 of the Year Finalist - Modified
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Short answer; No. I still do not have a manual for the C-4's. I keep waiting to get a good deal on a factory manual. so far all I have is the electrical one for the 84. These things are so new there not supposed to break yet!