Driveshaft Adapter MK4

[rsbrillhart]

My MK4 driveshaft adapter hole pattern seems slightly (~1/64th) larger than that of the pinion flange. I'm running 2015 IRS with a Ford 3.55 center section and a manual Tremec 600 transmission. My adapter is clear zinc and I just realized that the installation manual says that I should have received a yellow zinc for my set up, which I'm assuming may be my problem but wanted to confirm here before contacting FFR. Are the bolt pattern diameters on the two adapters indeed just barely different?

[GTBradley]

I received both but it was the clear zinc (silver) that worked. I have the same setup as you. I think I remember the holes being slightly bigger, but they matched up okay.

https://thefactoryfiveforum.com/attachment.php?attachmentid=108401&d=1559830663

[Jim1855]

Yup, it is. I have a yellow chromate (zink maybe), it was tight on two IRS flanges. I measured the two IRS flanges and the adapter multiple times. The adapter fits the driveshaft yokes but not the IRS input. I still have the adapter.
I've got all of the measurements somewhere.
Jim

[rsbrillhart]

Thanks for the replies. I was initially just trying to attach the adapter to the flange. I hadn't looked at matching up the driveshaft yoke to the adapter, until now. The four bolts holes are not even close. So I definitely need a different adapter and I hope the yellow zinc (chromate?) will do the trick. The 6 hole pattern to the diffy needs to be almost the same, but the 4 bolt to the driveshaft will need to be completely different. Guess I'll need to wait until the world settles back down and call FFR when they get back to work.