My tow vehicle has a 700R-4 (1989 Chevy C1500). Today I went to start it up and heard a loud clank. In first and Overdrive there is a loud clanking noise that varies in pitch with rpm. Second and third I hear no audible noise. I know it's something internal in the tranny, any idea what I'm looking at?

Thanks!

 

Well if it goes away in 3rd its likely a planet

 

Drove it home in third and it was fine......does a planetary require a full rebuild? I have 35K on this tranny but it seems that this truck eats transmissions! I looked on your site for a possible replacement, I'll keep that in mind if it comes to that..........

 

Requires total disassembly of trans and likly a rebuild

 

first thing to do is ck converter/flywheel bolts, then if their ok, get out the checkbook, lol

 

I've had that problem before. It was my Drum both times. The weld gets broke. But I went ahead and did a complete rebuild on it.