Hey guys, any help with this problem would be greatly appreciated. My buddy just bought a 84 F-250, 6.9, and a C6. I went to look at this truck a couple weeks ago and the guy told me it locks up in first gear, we took it for a ride and it started out in second and shifted into 3rd fine, no slipping, reverse worked fine. He made it very clear he had no idea what was wrong and that somebody told him it could be the planetary gears. What are those?

Anyway I decided not to buy it and told my buddy about it and we picked it up thursday. Only now it shudders, slips, first gear works and doesn't lock up anymore when you put it down in first. Reverse doesn't hardly work at all. Once you get it into 3rd it works fine until it has to downshift. So he changed the filter and fluids. It didn't make much difference, was really dirty in the pan though. Have also heard that the vaccuum pump could cause this problem possibly?

Also, what are the differences in the gas C6 and the diesel C6. Will they interchange, and how hard iis it to change the shaft from a 2wd to a 4wd, might have another tranny out of a gas 2wd, so the shaft would have to be changed to bolt to the transfer case I believe.

Alot of questions here, any info is greatly appreciated

Thanks, Dan

 

Thread moved to appropriate technical forum.

 

So does anybody have any info on this problem?

 

The direct clutches could be siezed up. This will cause a lcok up in first gear.
The transmission will have to be taken apart to convert it to a 4wd.
The output shaft must be replaced.