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Shiftless Automatic in a C4

Joined
Dec 27, 2001
Messages
160
Location
Matthews, NC USA
Corvette
1984 Coupe
While out driving around this weekend, my tranmission in my 84 stopped shifting into 3rd gear. Manually shifting would not work either.

Has anyone else encountered this problem before and if so, what was the prognosis?

I dread trying to find a "reputable" transmission shop here in Charlotte, NC.

I'm hoping that someone could give me suggestions on what to check.

Fluid level was low (about 2 quarts) and fluid is brown. After putting in the 2 qts. No change. (Unless you count the ignition going out too and leaving me stranded on the side of the road)

Ken
 

vigman

Motor head!!!!
Joined
Feb 13, 2001
Messages
3,471
Location
Valencia, CA,USA
Corvette
88 Convert ( SOLD ) /1973 coupe 4 speed/1964 Vert!
3rd or over drive?

How many miles???

and what about the ignition?

Mike
 
Joined
Dec 27, 2001
Messages
160
Location
Matthews, NC USA
Corvette
1984 Coupe
It's third. Arround twenty MPH, the trany shifts once and then never shifts again into 3rd. It seems to downshift ok when I come to a stop.

When trying to shift manually it doesn't seem to have a positive detent in 1st gear. Can't seem to pull the sifter back far enough in to first.

My son seems to think that the linkage may be screwed up and I may be starting the car in the 2nd gear position an not drive.

I don't know how driving could have done that.

Don't know about the ignition yet.

While trying to sort out the trany problems, the engine simply died and would not start. NO gas problems, cranks like it not even trying to fire.

when it rains, it pours.

Ken
 

vigman

Motor head!!!!
Joined
Feb 13, 2001
Messages
3,471
Location
Valencia, CA,USA
Corvette
88 Convert ( SOLD ) /1973 coupe 4 speed/1964 Vert!
This happend to me

Is reverse weird?
like the shifter dosen't line up correctly when you engage reverse & park is off as well

( park car on flat surface put car in park ) push backwards.. then see how far you have to pull it to get it out of park..I'll bet it's bearly engaged.


If you lift the car and have somebody inside shift,
and you assist underneath... you will see it's not
1 to 1.

The FWD part of my cable came apart.. and that was the problem the shifter would not go to the correct detent.

As far as your tranny.

Dump the pan..look inside.. change filter add fluid
& try again. AFTER verifying your cable is not working correctly...

Mike
 

c4c5specialist

Technical Advisor
Joined
May 29, 2001
Messages
3,682
Location
New Haven, Ct. USA
Corvette
Nope, but someday.
Hi there,
questions, what is your first to second shift like???
Does it occur very high in the rpm range?????
Please answer these questions, and we can proceed.
Besttoyou, c4c5:hb
 
Joined
Oct 30, 2001
Messages
2,273
Location
Glen Burnie, MD, USA
Corvette
1986 Bright Red Coupe
kmcewan said:

While trying to sort out the trany problems, the engine simply died and would not start. NO gas problems, cranks like it not even trying to fire.
Ken

Does it seem to crank faster than normal? Could be timing chain- not sure how often one will actually BREAK on a Vette, but I've known other GM owners who have had broken chains between 100 and 110k miles.

My old Subaru actually slipped its belt a couple of notches. Would fire maybe one crank in 50. Non-interference engine, though, so no damage even though it happened at speed.
[RICHR]
 

Jack

Well-known member
Joined
Dec 27, 2000
Messages
1,825
Location
Florence, SC (Timmonsville SC)
Corvette
71 War Bonnet Yellow VERT 71 BH Blue CPE (SOLD)
Broken Timing Chain

I've not seen a timing chain break either ... BUT ... many sbc's have PLASTIC-shrouded teeth on the cam gear. The plastic teeth will break off (got that t-shirt) and will give same effect as though chain has broken. Simply remove the remove the distributor cap and have a helper crank the motor ... while watching the ditributor's rotor. If the distributor's rotor does NOT rotate smoothly, then you probably have a timing gear/chain problem. If gears/chain are bad ... replace with set known as a "true roller."
JACK:gap
 

Jack

Well-known member
Joined
Dec 27, 2000
Messages
1,825
Location
Florence, SC (Timmonsville SC)
Corvette
71 War Bonnet Yellow VERT 71 BH Blue CPE (SOLD)
Plastic cam gear teeth in pan/screen

BTW, if plastic cam gear teeth break away ... they WILL find their way into oil pan:eek & oil pump pickup screen:eek. If so, do drop pan & clean out ... replace (don't clean, but replace) the screen.
JACK:gap
 

vigman

Motor head!!!!
Joined
Feb 13, 2001
Messages
3,471
Location
Valencia, CA,USA
Corvette
88 Convert ( SOLD ) /1973 coupe 4 speed/1964 Vert!
One thing at a time

The linkage is a PUSH style so on the tranny the furthest position FWD is park, 1 click back rev etc etc.

So the failure is the cable comes out ( on the backside of the clamp) and you cannot push as far fwd as you need to .

When you in PARK your bearly out of reverse etc.The pointer on the center console will reflect this.

To test the linkage cable,Remove the cable from the tranny and push it back HARD..I'll bet the sheath pops out of the crimp where the clamp is.

The shifting into O/D might be related to this problem ( or a contributing factor).

The two quarts low & brown is a killer though, remove pan clean & inspect.

The no start condition.
Check to see if you have spark.. you know how to do this, right?

Remove the MAF & wires.
Squirt some quick start down the throttle boby hole, if it fires, then you have a fuel problem.

If it doesn't fire but you have spark.

Get a timing light & crank, if you can't see the line up pointers anywhere in the timing zone
(and the strobe is firing) you,ve got a timing chain problem.

Mike
 
Joined
Dec 27, 2001
Messages
160
Location
Matthews, NC USA
Corvette
1984 Coupe
The shift from 1st to 2nd takes a little longer than normal and shifts fairly hard. Not neck snapping, but noticably harder that I would consider normal.

RPM at shift does sound higher than normal but I don't have a number.

Gear positions on the console appear to be lined up properly and reverse dosen't seem to be in a weird position.

Timing Chain problems is possible I guess, but I think unlikely in this case. I've driven a car years ago that jumped time and the results were quite noticable. Back firing, and all sorts of nasty noises.

This died very quietly. I didn't even know it had died until there was no throttle response. Not even a hint of firing when the engine is turned over. I'm assuming that a fuse was blown or something electrical came loose.

Transmission shops are notorious around here for ripping people off so the more I can diagnose myself, the better off I'll be.

Thanks for all the help
 

Jack

Well-known member
Joined
Dec 27, 2000
Messages
1,825
Location
Florence, SC (Timmonsville SC)
Corvette
71 War Bonnet Yellow VERT 71 BH Blue CPE (SOLD)
Mine died just like yours

Ken:
Mine died quietly & quickly at low rpm's with no hint of a problem ... in my case it was plastic gears. Worth taking a look into.
JACK:gap
 

vigman

Motor head!!!!
Joined
Feb 13, 2001
Messages
3,471
Location
Valencia, CA,USA
Corvette
88 Convert ( SOLD ) /1973 coupe 4 speed/1964 Vert!
Timing gear description

It dosent say in the book if it's a plastic covered gear or not, and no good pictures.

Anybody know for sure what's in there?

I'll check a Sport Imports tommorow...George has a passel of partially disassembled engines and have a look.

So no progress???

Bummer

Mike
 

vigman

Motor head!!!!
Joined
Feb 13, 2001
Messages
3,471
Location
Valencia, CA,USA
Corvette
88 Convert ( SOLD ) /1973 coupe 4 speed/1964 Vert!
Shift point adjust

When the car is running again

You can adjust the shift FEEL & point by adjusting the TV ( Throttle valve ) cable that goes up to the
throttle body. the tighter you make the cable the more pressure internaly happens ( well it's a lot more than that but,) and the shifts become harder.

If you back off, the more prone to slipage you are..in a older tranny..thats death!

And DO NOT power flush the tranny!!!! Under any circumstances.

Mike
 
Joined
Dec 27, 2001
Messages
160
Location
Matthews, NC USA
Corvette
1984 Coupe
No progress yet unfortunatelly. The car sits outside right now and the weather isn't that great for diagnostics.

I do feel a sick day coming on though.

I plan to take the vette (once running) to a place where I get the oil changed. The offered to do a trans service two weeks ago and I didn't have time. Looks like I have time now.....

What exactly is a power flush?


Ken
 

vigman

Motor head!!!!
Joined
Feb 13, 2001
Messages
3,471
Location
Valencia, CA,USA
Corvette
88 Convert ( SOLD ) /1973 coupe 4 speed/1964 Vert!
Power flush

A way to get money out of your wallet.

When you service the tranny it loses about 4-5 quarts ( depending on make...etc) of tranny fluid.

You clean the pan ( getting ALL that junk out of the bottom ) and clean the fliter, new gasket... and off you go.

This only changes 5 out of the 12 quarts in the tranny.

Some brain surgeon decided to tap into your tranny cooling line and use the tranny to pump ALL it's fluid out and feed new fluid in at the same time.

Sounds good on paper ...right...

But you havent changed the filter ( which is still partially clogged ) and you don't know whats lurking in the pan.

And you have nice fresh fluid going around loosening MORE slime.

The fluid turns Brown for 2 reasons.
1) The dye is heat sensitive so it changes color with temp.

2) If you have friction material shedding (clutch packs) that releases microscopic stuff in the fluid
also changing it's color AND viscosity (thickness).

If you change the friction of the fluid, thing will slip easier... now we all know that PRESSURE compresses the clutch packs but, if the material is gone,and clearences are larger it's not going to take much to get it to break away.

If that wasn't enough... the little bits of stuff floating around gum up the shift servos,valves & passages.

THE POINT IS less is more... do a little at a time
disturb as little as possible or go for a full rebuild

Mike
 

Jack

Well-known member
Joined
Dec 27, 2000
Messages
1,825
Location
Florence, SC (Timmonsville SC)
Corvette
71 War Bonnet Yellow VERT 71 BH Blue CPE (SOLD)
convertor fluid

I agree with Mike ... forego the powerflush.

The convertor's holding a lot of the fluid ... and it's a major PITA to pull it. The convertor in my 71's TH400 does not have a drain plug. I've seen some cars (can't remember which) that had a removable factory plug. After you've changed filter, you might keep adding fluid while running engine with a line loose at cooler ... sort of a continuous dilution process ... did it on a RX7 one time ... it worked. Many years ago, I saw a convertor that'd been drilled and a small self-tapping screw put in it for draining ... haven't a clue if it held up or affected balance significantly. Anyone else have knowledge of the convertor screw trick?
JACK:gap
 
Joined
Dec 27, 2001
Messages
160
Location
Matthews, NC USA
Corvette
1984 Coupe
After the ignition died this weekend, I left the vette alone until this evening.

I cranked it up and it started, but ran very rough. I ran it for about 3 minutes at about 2000 RPM. Let off the gas to go to idle and the engine died. Couldn't restart it.

I'm not sure now what to blame this problem on.

Any ideas out there?

Ken
 

vigman

Motor head!!!!
Joined
Feb 13, 2001
Messages
3,471
Location
Valencia, CA,USA
Corvette
88 Convert ( SOLD ) /1973 coupe 4 speed/1964 Vert!
You mean aside from the other suggestions?

Did it throw a check engine light?

Take off the air cleaner.. when it's cranking do you see a fuel spray down the throttle bodies?


How's the cap & rotor... when did you change em last?

Try removing the fuse for the ECM for a few minutes
( reseting the ECM ) and put it back.. the car will have to relearn all the engine parameters.


When you first turn the ignition on the check engine light does work... correct?

Mike
 
Joined
Dec 27, 2001
Messages
160
Location
Matthews, NC USA
Corvette
1984 Coupe
Mike,

Remember, this is a different motor than the original, and I'm dealing with a Holley Carburator and Edelbrok intake.

Check engine light is always on and has been since I got the car.
I'm not sure that the ECM is sensing anything on the Engine at this point.

I got all the tune up parts this weekend but haven't done the tuneup yet. I have cap, rotor, plug wires & plugs. The failure seems heat related and may very well be in the cap. I seem to remember that HEI ignitions easily find flaws in the ignition system when warmed up.

I'm starting to think seriously about finding a complete 84 engine somewhere and not dealing with this crap anymore.

Ken
 

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