So a few weeks ago I went to take my 80 Corvette that I purchased a few months ago on its first "long" drive to go get it inspected. I get about 6 miles into my trip and the transmission starts slipping out of 3rd into 2nd. At first I shrug it off as it went back to 3rd and drove fine. Then 2 miles later it did it again. So I started looking for a place to turn around. Then after I got turned around, it would no longer shift to 3rd and then about 6 miles from my house I only had first so I limped it to a friends house for a little less than a mile after that. I wasn't going to leave that car on the side of the road. I towed it home the day after and load/unloaded it under it's own power.

I let it idle when I got it into the garage and discovered the transmission fluid was way overfilled. I neglected to check the fluid before my take off. I should've been more through going over the car. The transmission had been flushed a few years ago by some Corvette shop according to the PO.

So fast forward to where I am at now. I did some research on the forums and came up with some possible causes of my problems, other than the overfilling. Came up with a Stripped Governor Gear and a failed Vacuum Modulator. I am pretty certain the Vacuum Modulator is gone since when I stopped at my friends house, the car was smoking (white smoke) from the exhaust. So I believe its sucking tranny fluid from the Vacuum Modulator.

So with my information, I pulled the Governor Cover off and about 2.5 quarts of fluid came out. Confirmed the overfilled theory. And I pulled out my governor. It checks out.

My predicament now is when I decided to get the parts to go ahead and do a filter, pan, and gasket replacement as well as a new Vacuum Modulator. When I dropped the pan and saw what was settled on the bottom and the color of the fluid is more like Strawberry Juice than clear red fluid. I am now concerned that the tranny is junk. I really don't want to rebuild this transmission as I am planning on going to a 2004r next year. I was initially planning on running the TH350C for at least next summer after I got my built Vortec 350 in.

Sorry for the long post. Just looking for any insight if my transmission is junk or not. I also discovered that the connector for the lockup is unplugged. I have yet to locate it in the car either. I'm attaching the picture of the inside bottom of my pan.

 

I see a lot of money laying in your pan. Looks like clutch material.

 

Looks like someone rebuilt it in the past with the good RED Alto clutches.

 

Sounds like I'll be swapping a new transmission in with my Vortec build then. More money. I was hoping to drive it until it got too cold to see if it needed anymore work done to it.

 

No expert on TH350s but, it doesn't seem likely the tranny was overfilled three yrs ago. It would have burped quit a bit out on the ground during winter storage. Instead, I suspect the pump is no longer building pressure. So you have excess fluid in the pan, burned & slipping bands and a tranny that refuses to shift. Basically, most of the fluid is in the pan instead of up in the valve body and torque converter perhaps.

 

I didn't give that a thought. I didn't have the opportunity to see if there was any ATF on the ground since the guy had it outside for me when I went to look at it. The battery was junk so I couldn't drive it either.

 

Check the coolant in the radiator. Looks like the cooler in the radiator leaked. I wouldn't be surprised if the coolant looked pink too.

If you'd caught it right away it might have been able to be flushed. But, looking at that pan picture, i see too much clutch material to expect it to still be good. But, you might want to try a flush anyways and see what it does.

 

Went to 350 school the first year they came out and forgot all I learned. But handled a problem such as yours where it down shifted and seemed to hit passing gear. I had a talk with a pro and we decided it was the direct clutch drum worn where the rings seat. That was it! The wear was very little but with a good used drum all worked good.
I would have to agree with the comment on the material in the pan. I think your going to rebuild that one.

Dom

 

So I think lionelhutz is right about my transmission. I haven't drained the coolant yet, but given that the ATF looks likes Strawberry Juice. I think the transmission cooler in the radiator is leaking and got coolant in my transmission. So I am gonna dump some ATF back into it and move the Corvette to my other bay in the garage and the transmission will be coming out. I probably won't be rebuilding the TH350C. I'm just gonna swap it out for a 2004R. I guess this is what happens when you buy a "cheap" C3 Corvette that sat for 4 years. I'll have it on the road next summer. I can take my time with the motor swap and transmission swap over what appears to be another long winter.

 

In 2013 I went after my TH350c tranny leak that turned out to be the large pump O-Ring was rock hard.
I pulled it and fully rebuilt it myself because; I was leery of a shop messing something else up and of course they say, "it was already like that"
Good thing I pulled it as one of the planetary gears was eating into the housing.
A local trans shop (I know the guy) had all the used/very usable hard parts I needed...I did install new clutches and a few steel disks along with a high quality rebuild kit, Oh and a rebuilt TC.
I would encourage anyone to do a little research; I actually got an excellent DVD with a step-by-step instructions showing detailed inspection, what to look for, how to properly take measurements and reassemble.
I saved thousands and had pride in my work too.