I know, I know, toss it in the trash. That is the intent. but until I do, If need to know what to do if this occurs again.
1985 C4

A while back I took the car to get the oil pan gasket replaced. I drove it to the shop and all was working ok except for reverse. However reverse is not the issue here. The next day the shop called me and said that the transmission was locked up. Though they could put the stick-shift in gear, The car was locked up and would not roll. It would not roll in neutral or in gear. The car would start with the clutch pushed in but it would die as soon as the clutch was released. It felt like the tranny was locked up or the emergency brake was engaged. Nothing forward or reverse. So I had it towed to the corvette shop. He said,"I think I know what it is" and that is it. He didn't tell me but the next day I drove it home. No charge.

Never did get the oil pan gasket replaced. Kinda got distracted.

SO, What is happening? What would cause it to "lock up" but be an easy fix for no charge if one knows what it is?


Any thoughts? Yeah Ill probably toss out the tranny later.
I appreciate your time.

 

Its a planetary set with clutch packs... can't really see it locking up... and if it did you certainly wouldn't be able to drive it after...

 

Most likely there is enough slop in the shifter that the first shop got the transmission stuck in two gears at the same time. Easy fix when you have a lift.

 

There is also a possibility that there is excessive wear in shifter shaft cams and palls, so with a sloppy shifter and worn palls it is sometimes possible to get two gears at once.

Normally the pall ***** and plug don't allow two gears but wear can allow enough room for this to happen.

to get car moving again raise up car manually move levers to the neutral position.

 

That seems more reasonable.

 

There is also a possibility that there is excessive wear in shifter shaft cams and palls, so with a sloppy shifter and worn palls it is sometimes possible to get two gears at once."

time for more of my ignorance to show. UGH...here goes -"shifter shaft cams and palls" Are tehy inside or outside the transmission?

I build radio towers not transmissions. be kind

 

Its your shifter that’s worn out.
the trans is probably just fine.
i put a 4+3 in my 57 chevy truck and it works great!
but every once in a while the shifter leaves it in the last gear, and lets me try put it In Another gear, and usually, i can tell , pull over, play with the shifter, and its good for a long time.
the key is to grease the shifter once in a while.
but since nobody did on your car, the shifter has worn.
on my truck, i used a Hurst competition plus. Its been in there about 20 years, and 200,000 miles.
But because of how your car is designed, u don’t get that option.
BUT!
I have an 84 shifter for sale with linkage arms and a boot for $175.
sorry, when your shifter starts missing shifts, no amount of grease is going to replace the metal that has worn away.
try greasing your shifter to see what happens. It might just fix it.
where the metal sections are stacked together, try putting grease on the end of a screwdriver, and move the stick back and forth while sort of pushing the grease between the levers That slide together.
also, on Amazon, they sell a universal drain plug.
i drilled a hole in my pan and installed it.
i can change fluid in about 30 minutes start to finish.
you can’t clean all the sediment out of the pan, but my fluid is always clean.
when the fluid is clean, you’re not pushing Dirt through your overdrive. It will last longer.

 

It's possible it's something inadvertently caused by repair shop. The 4 +3 has a unique (B.S.) situation the shifter mounts to the floor/ tunnel and not the transmission. When engine is raised to remove pan it can stress shifter assembly and rods. Something to look at.

 

Did you ever figure out what happened exactly? I’m having the same problem with my 4+3. I tried disconnecting the shifter linkage and manually put it in neutral but unless I’m doing it wrong, it’s still locked up.

 

It's pretty much a you can't screw it, as long as the forward gear arms are in the 12:00 position with the rods above and the reverse coming up from the bottom with the arm pointing +- 7:00 your good.

Now if from the outside your good and still locked up and you dont feel the notches when moving the arms (and you should)because I have seen a few broken shifter arm shafts over the years, which requires the side cover to come off to take a look at things and that's not a big deal it's just a smelly job with the gear oil.

 

Thanks for the response! I got up underneath of it today and moved the forwards to 12 and the reverse to 7 and still had no luck freeing it up. I drained the gear oil, which looked good, and removed the side cover. Everything looks fine. I’m at a loss. I would have to pull the transmission if I don’t have to. The engine starts fine and before messing with it, it ran through all gears as smooth as normal (with the clutch in). Do you have any other ideas? You’re the only person who I’ve got any information from INCLUDING local dealers!lol so I thank you again for your time and response!

 

Thanks for the reply. It was in neutral before taking the cover off. I accidentally moved that selector lever when taking it off. I had both forwards at the 12 o’clock position. Inspecting it, everything looks fine. I literally have no idea where to go next. Could it be something in the overdrive unit?

 

I didn’t see that second part. I will give it a try and get back to you! Thanks again man

 

Okay I got you now.



Like this? All four golden rings are now visible. If so, I still cannot get it to rotate.

 

I can see al least 1 chip out of a gear shouldn't be enough to lock up, with all the Brass's showing it should move. Try playing with the reverse and I'm sure that's a redundant statement.

Now I'm sure the next step is a trans pull so once you get the drive shaft pulled we can rule out if the rear is whats locked up

 

Thanks man! Actually, the first thing I did was remove the drive shaft from the differential. It was hell but it was the only way I could get the car to roll in order to push it into the garage. It’s the crazy it’s thing. The car starts, runs fine, goes through gears with no grinding, but just won’t move. Release the clutch just kills it. I guess out the trans shall come!

 

Hold on when you let out the clutch does it stall the motor like your in fourth gear on a mountain or does it not move at all in any gear and engine runs
either way out it comes something isn't happy

 

Thanks for the response to all you. So there was plenty of gear oil. There was a tad bit of metal dust that I collected with a magnet. I mean just a very small portion. However, sitting on the bottom of the gear case was a full sized washer. It wasn’t torn, beaten or broken. A full size washer about 3/4 inch in diameter. It blows my mind how it got there unbroken or not chewed up lol I pulled the transmission today and is in neutral. The gears spin perfectly while turning the input shaft. However, the output shaft is completely locked up. It has to be an issue with the overdrive unit. I bought the car a couple of months ago and the overdrive never worked. I wasn’t too concerned as I just planned on short distant drives. I wish I would’ve inspected it more thoroughly in hindsight. Could a failed overdrive unit literally lock the transmission up that you know of?

 

I guess a if a piece of reckage could find its way into the pump case and that would stop the shaft dead, but on the other side the power of the driver line would shatter the pump.

Since the trans is on the ground separating the Box from the OD is not a big deal.

 

thanks for the info. I’m having a hard time finding a replacement overdrive. There is one full trans on eBay but it will be about 2k with shipping. I’m in a bit of a pinch financially and 2k is a bit out of my price rang. Does anyone know where I could find one? Here are a couple of pics of the case separated. I really don’t have any knowledge as of what my next step should be. Any info is greatly appreciated. (Whether or not it’s repairable). The picture with the washer is what I found sitting on the bottom of the gear case. I’m curious if anyone knows just what it is. Thanks in advance