New to square bodies. Th400

[K203295]

Hi guys,

I’m new to these trucks. I bought one for the simplicity of them. However, I’ve run into an issue that is stumping me. I have an 84 K20 with the turbo 400 transmission. It was rebuilt a year ago by the previous owner. I recently developed an issue where once the trans heats up about 15 min into my drive, I develop a ticking noise in the transmission. It sounds exactly like an exhaust leak. Once I come to a stop and sit for a few minutes, it goes away. At first it was just the ticking but the other day, after it started ticking, smoke started pouring in the cab. I pulled over and saw my front driveshaft and belly of the transmission was dripping with trans fluid. I couldn’t find any obvious areas on the side or bottom of the transmission where it was leaking. It looked like the top of the transmission was wet. Almost like it was coming from the vent tube. The trans lines run into the radiator so I’m sure the lack of a cooler isn’t my issue. The flex plate is new in it as well and doesn’t seem cracked. Any ideas or suggestions? This thing has me stumped.

Thank you for the help!

 

[Charlie]

 

[1985c20]

What's the fluid level on the dipstick? It should only read full when the transmission is fully hot like 200 fluid temp. If its to the full mark when you first start the truck it will come out the vent as the fluid heats up. No idea on the ticking noise sorry.

 

[idahovette]

Does it have a cover on the bottom of the converter? Is it metal or plastic? Sometimes the cover will shift and come into contact with the converter especially if it is plastic

 

[Shorty81]

Welcome David, I'm just 10 miles South of you.

 

[QBuff02]

More than likely if it was rebuilt properly, it's over full. Had similar issue on mine, and when I drove it and the fluid got hot it would push out the vent on top of the transmission and get on the right exhaust pipe and make a smoke screen. It was about 2 qts over filled. Once I drained a little off I haven't had a problem since. The other place to look at is the sealing grommet at the base of the dipstick tube, if it's cracked/dryrotted or deteriorated it will develop a leak out of it as well. Or if someone didn't put the bolt in on the bellhousing that holds the dipstick in place it could be working loose also. As for the ticking, it is quite possible that the bolts on the flexplate are loose or it has developed a crack and is starting to come apart. Just a couple things for you to check.