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9/25/10 1:50pm - Original Message: 'auto trans does not engage'
74-454 Lifetime Member
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, - Canada

Vette(s):
Coupe 74 - 454 Drive it like you stole it!

Joined: 8/6/2004
Posts: 533
After sitting 2 years; I just replaced all the u-joints, so I manually rotated the shafts if it makes a difference.

Was going for my first drive and after the engine warmed up; I noticed that it does not get into any gear.  I moved the lever almost 20 times between all the gears (and sometimes gave gas at different gears).

Nothing is happening.

I have all my books opened and looking through the web, but I'm not finding much.  There's a lot of info to digest.

In the meantime, if anyone has any idea of where to start; I would appreciate.

I have a transmission filter and gasket here, so I don't mind replacing the fluid (which I haven't looked at to see if it's still red or burnt).

Other info: while replacing the u-joint; I was able to move the trans. between park & neutral to rotate or block the axle and that worked fine.

It is the original automatic THM400 in a '74 big block.

Thanks,

Steph.
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9/25/10 2:14pm - Reply: 'auto trans does not engage'
dskopp
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Oak Creek, WI - USA

Vette(s):
1981 Great White Shark. Red Interior, 350/190hp. PS, PB (SS), A/C CC, T-Tops, Going to remain as Stock as possible. Served three years in Active Duty Army, then Retired Air Force after 34 years! Badger State Vetts Car Club. 175,000 Original miles!!

Joined: 5/21/2008
Posts: 1956
I would look at and change the fluids Steph !!  You have no "pull" from the engine to the transmission??  Could be a tranny problem.  I wish you luck!!
Dan


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9/25/10 7:32pm - Reply: 'auto trans does not engage'
Adams' Apple Lifetime Member
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Duncanville, TX - USA

Vette(s):
#1-1974 L-48 4spd Cp Med Red Metallic/Black deluxe int w/AC/tilt/tele./p/w-p/b/ Am-Fm/map light National/Regional/Chapter NCRS "Top Flight" #2-1985 Bright Red/Carmine Cp.L-98/auto Member: NCRS, NCRS Texas, Corvette Legends of Texas

Joined: 11/8/2003
Posts: 19447
OuchRuh Roh!!!Shocked
When you moved it from park to neutral while doing the u-joints, did you use the shifter, or manually move the linkage underneath?
First thing is to check the fluid, of course. Make sure it is full.
I assume it was working OK when ya parked it?
Only a few things that can cause the trans to not engage...all but a couple of them are bad news.
Check the fluid.
Check the shifter linkage at the trans to make sure it is actually moving when you move the shifter on the console.
If the fluid is full(regardless of condition), and the shift linkage/cable are working properly, the next step is to pull the pan, and have a look-see. With the pan off, move the shifter linkage and see if the internal linkage is moving the valve on the valve body. The 400 has a nail-shaped pin(on the internal linkage) that sits into a slot on the manual valve, and moves the valve as the shifter is moved. The nail/pin must be in the groove of the valve...if it isn't the trans will be stuck in whatever gear the manual valve is positioned in. Chances are, if the trans was working when it was parked, then the linkage is gonna be ok, but it does need to be verified.
IF the fluid is full, the external linkage is good, and the internal linkage is good....the sad prognosis is that the trans will need to be pulled and rebuilt. The rubber seals in the trans will dry up/shrink over time, especially if just sitting. Once the seals shrink, and become hard, they just will not seal, and the fluid pressure will just blow right past them, and you get no movement.

One thing you might try to verify a hard seal issue is to let the car run for 30 minutes or so at idle, then try to see if it will engage. If it does after running, then the seals are hard, and it will still need a rebuild. If you let it run, and it's up to normal operating temps, and the thing will still not move, then it may be more serious than just seals, but will still need to come out for repair.
Basically, if it's full of fluid, the linkages are all good, and it still won't move, it will have to come out for repair...no other way around it...
Even if you pull the pan, and see some gunk in it, that in itself would not keep it from moving forward AND reverse...it would have to be totally burnt to a crisp for that....which means it would have been like that when it was parked.
Wish I had better news, but...it is what it is...


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Joel Adams
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9/26/10 10:06am - Reply: 'auto trans does not engage'
yostusota
Former Member
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York, PA - USA

Vette(s):
1969 daytona conv. all original 350 350 380 4 sp w/air..and hard top

Joined: 5/18/2010
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I was hopeing you would see this one Joel !!!  Hopefully it's just the linkage out of adjustment!!!
Rich
 


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9/26/10 12:15pm - Reply: 'auto trans does not engage'
74-454 Lifetime Member
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, - Canada

Vette(s):
Coupe 74 - 454 Drive it like you stole it!

Joined: 8/6/2004
Posts: 533
I moved from park to neutral (back and forth quite a few times) from the shifter; not the linkage (didn't know you could do that...).

I looked at the fluid right 15 minutes after the engine was shut off (after idling for almost 10 minutes).  Since the engine was shut off; I don't know if the level is correct; but from a color/residue/thickness and taste perspective; it looks really good.  Unless I have to remove the pan, I don't see a reason to replace the fluid at this stage.

I am also hoping it is "just" the linkages; but what Joel said about the seals makes a lot of sense; the car sat for a while; so I am expecting a few surprises here and there because of it.

I won't be able to look into it until tomorrow night.  I'll keep you guy's updated.

Thanks again!

Steph.
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