Long story short, swapped the t-19 to zf5 in my 460 truck. First time around, front seal went south and poured synthetic atf all over the brand new luk clutch. Pulled trans and replaced seal, reinstalled, cleaned clutch with a couple cans of brake cleaner.

clutch is slipping like crazy still, almost like it’s not fully engaged. I did notice the luk throw out bearing was taller than the t-19 unit. I re-used the t-19 clutch fork, had to enlarge the opening to accommodate the larger diameter throwout bearing. Had to compress the clutch fork quite a bit to reinstall slave cylinder.

Clutch adjustment rod has no affect on the clutch engagement, just where the pedal feel is.

i ordered the correct zf5 clutch fork the other day, hoping it is tapered back somehow that allows the slave cylinder to relax fully and hopefully engage the clutch fully. Any experts know for sure? Anything else I should check or I did wrong?

 

Having to squeeze the slave back to get it in place is normal, the new slaves come with a plastic retainer that holds them back till you get it installed and then you cut the retainer straps. The correct fork is a good idea. After you install it I would drive it and see if it gets any better on it's own.

If everything starts working except you get a lot of clutch chatter, you may end up getting another clutch disc, they are sort of like brake shoes, once they get soaked they sometimes never recover.

 

Clutch fork done the trick, thanks!

 

Was your ZF sitting for a long time? Or was there another reason the front seal went bad?
The one I have has been sitting for 2 years and seeing your post has me wondering if I should replace the seal before installing it.
If I had the money I think I would just have a trans shop break it open and go over it.