92 gmc 3500 4l80e 7.4l tbi
 

I have 92 had 3500 454 tbi with a recently rebuilt 4l80e. I was getting trans fluid blown out the dipstick tube. So I cleaned the vent on top of the transmission. I blew through the cooler in the radiator. It was clean. Now even on a cold startup it will puke all of the fluid out the top vent. I added a large aftermarket cooler. But it still does it any ideas. The vent on top doesn't have any rubber hose at all just the metal vent new remain torque converter. What would cause this. The fluid smells slightly burnt.

Re: 92 gmc 3500 4l80e 7.4l tbi
 

Check the fluid is not too full.
Mine has a piece of rubber tube about 18" long that goes up next to the distributor.

Re: 92 gmc 3500 4l80e 7.4l tbi
 

Thanks and GOD BLESS

Re: 92 gmc 3500 4l80e 7.4l tbi
 

The C trucks have the little round vent directly on the transmission. The K trucks had the rubber hose.

Can we get some more info? Why did you replace the torque converter? Did you have anything done to the transmission when you had it out?

Re: 92 gmc 3500 4l80e 7.4l tbi
 

Well, curiosity finally got to me. I crawled under all three of my pickups on the weekend. 1x93 dually, 1x 98 RCLB, 1x 97 RCLB. All three have about 18" of rubber tube attached to the breather line. It may be because all of these are imports to Australia, I don't know.

Re: 92 gmc 3500 4l80e 7.4l tbi
 

Thanks for the info. I found a blown cooler line. I jumped to conclusions.