Auto Trans Slipping-Help!!!
Thread Starter
Intermediate
Joined: Jul 2007
Posts: 40
Likes: 0
From: Springfield MO
Auto Trans Slipping-Help!!!
My first vette is a 1977 L48 Turbo 400 auto. Been running great, has been leaking a very small amount of trans fluid in the garage, fluid looks clean and no smell, took it out for a spin and wouldn't shift out of first.
It will shift manually through the three gears but not on it's own. Fluid okay no odor. Tried to slide under to look and almost knock myself out>
Can"t identify exact leak point. Modulator? (looks like a fuel pump) hose is cracked. I don't know much about this beast.....but I love it. Would appreciate the brothers here giving me some ideas! I am hessitate going to a transmission shop, for obvious reasons, but will probably do that. Please advise a newby brother here. Thanks so much!
It will shift manually through the three gears but not on it's own. Fluid okay no odor. Tried to slide under to look and almost knock myself out>
Can"t identify exact leak point. Modulator? (looks like a fuel pump) hose is cracked. I don't know much about this beast.....but I love it. Would appreciate the brothers here giving me some ideas! I am hessitate going to a transmission shop, for obvious reasons, but will probably do that. Please advise a newby brother here. Thanks so much!
Team Owner
Joined: Jan 2006
Posts: 37,637
Likes: 3,116
From: Crossville TN
Fix the hose and seal up the vacuum leak. Chances are that will fix it. If you find that tranny fluid is getting into that line, the vacuum modulator has ruptured its diaphragm and it needs to be replaced.
Drifting
Joined: Jul 2005
Posts: 1,562
Likes: 2
From: Spring Texas
Ought to be a Turbo 350 if original. Leak may be from the fill/dip stick tube. If you let them sit, the converter may dump fluid. Shifting issues may be fluid related (full? or not?). Hope its the vacuum servo.
Thread Starter
Intermediate
Joined: Jul 2007
Posts: 40
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From: Springfield MO
Safety Car
Joined: Oct 2000
Posts: 3,593
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From: Southern Indiana
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Race Director
Joined: Sep 2001
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From: Wellington, FL
St. Jude Donor '11 thru '25
M40 is just the RPO number; it does not mean the tranny is a 400. I have a '76 and the sticker says M40 but it's a 350 tranny. M40 is the RPO all the way back to '68 according to Black Book. 
Thread Starter
Intermediate
Joined: Jul 2007
Posts: 40
Likes: 0
From: Springfield MO
AAAHH HHAA! I simply don't know. I asked about the identifier in an earlier thread which was identified as the turbo 400. Sounds like it is probably the 350, which sounds right. Thanks.
Team Owner
Joined: Aug 2006
Posts: 24,125
Likes: 15
From: Columbia Missouri
Hey Burner, do you get up to Columbia very often?
I also had a modulator problem a few days ago. My trans wouldn't shift out of first at all, and the hose was cracked and slid off.
It's running great now with a new hose.
I also had a modulator problem a few days ago. My trans wouldn't shift out of first at all, and the hose was cracked and slid off.
It's running great now with a new hose.
Thread Starter
Intermediate
Joined: Jul 2007
Posts: 40
Likes: 0
From: Springfield MO
Mathew, I was really happy my first new corvette didn't have a big problem. Runs great now. Don't get to Columbia since my daughter went to school there (short time), you ever in Springfield, we could have a good time. Back on thread, forum brothers have been real helpful and helpful. Thanks and stay in touch.
