Hello everyone!
I've had problems with my 1990 K1500 6.2 diesel with 700r4. The truck shifts from 1-2 and 2-3 nice, but on third gear the transmission shifts weirdly to "neutral". It's not right after the 3rd gear engages but when i'm going 50kmh/30mph it suddenly pops to neutral. Downshifting works fine. I've replaced the TV- cable and it should be adjusted correctly and i've replaced the governor also and changed the oil and filter. I guess the next part would be to check the clutches if they are burnt but the old ATF was bright pink, it didn't smell bad/burnt and the transmission didn't make any weird noises. ATF level is correct and there wasn't any major particles in the transmission oil pan. Do you guys have anything in mind to help me out with this problem?
Thanks to all!

 

I am not an expert at all with automatic transmissions, but at 30 years of age, your Chevrolet 700R4, if original, has outlasted many other automatic transmissions. They were built to last back then, with few overseas-manufactured defective parts. Since you've replaced the governor and installed a new TV-cable and adjusted it properly, my only guess is that the 3-4 clutch pack might be the issue that is causing this problem. I would not wait long to repair it. As a professional driver, I am aware that a "neutral" condition, particularly at high speeds, could result in an accident if you need to move out fast when things go south.