Have a friend who found a super rare Chevy CC, dually, 4x4 with a ZF-6 behind a Duramax.
4th gear pops out when coasting, and he's trying to get a line on parts before he takes out the trans and opens it up.
Dealers keep telling him parts are no longer available through GM.
Does anyone know if the Duramax ratios are the same as the Powerstroke. So he could possibly go through Ford for internal parts.
Thanks

 

The ratios shouldn't matter as the drive gears likely are not the problem. Source parts using the part/model numbers on the tranny through a ZF parts distributor rather than GM.

 

Try Rockland standard gear for parts.

 

Google this secret code: ZF 6 spd tranny parts

 

Try Midwest Transmission https://www.midwesttrans.com/zfs_650.html