Thanks for all the info and links. Still not clear however, do I have to buy a new flywheel to get a clutch that will work with the ZF 5 speed?
The T 19 jackshaft is 1 1/8 th X 10 spline, the ZF 5 spd. is 1 1/4 X 10 spline so it's a given the clutch disk won't interchange. Same for the throwout bearing, internal diameter is bigger on the ZF, also the clutch fork has to be changed. That I've got covered so far [it's only money at the parts counter, right?].
Question that I still can't answer is, Can I just buy a 12 inch clutch that will fit my present 2 bolt on 3 pattern 6.9 flywheel, or do I ALSO have to now buy a new flywheel [heavier] with the 2 bolt on 4 pattern to fit a 12 inch clutch to the ZF 5 spd?
Yes, you need a new flywheel. The ZF flywheel is the same diameter, but it is almost double the thickness of a T-19 flywheel. Take a look at the first picture I attached. I don't know if a 2 bolt on 3 pattern clutch exists that would fit the ZF, but based on the thickness difference alone, I would
strongly recommend just replacing the flywheel. Besides, this will make it easier to find clutch parts in the future.
Also, regards the rear trans mount on the ZF, is it the same as the T19? Same location and mount? Or is there an issue there that will bite me when I try to put it all back together?
I'm honestly not certain. There IS a difference in how the 4x4 T-19 is mounted to the crossmember, although after looking at the two crossmembers as compared to each other, it looks like the ZF mount COULD have been put on the T-19 crossmember without any difficulty. However, I'm like you in that I wanted to have all my ducks in a row, so I had a ZF crossmember (actually, turns out it was for an E4DOA
but it worked anyways) ready and just went and swapped them without trying to fit anything to the T-19 member. Look at Picture #2...the rubber mounts on the T-19 crossmember are for a second metal piece, that the actual tranny mount goes onto (no picture of that piece, sorry). I didn't measure height differences, and it looks like there ARE slots in the T-19 crossmember that the ZF mount could go onto. Again, I'm not sure...IMHO it'd be best to have a ZF crossmember handy, and if you want to make the T-19 member work, you'll have a backup to keep you from being off the road too long in case it doesn't work. If you can make it work, please report back!
I spoke with a fellow who sells gear vendors a lot and according to him, it's possible to use the rear housing on a 4X4 ZF in a 2 WD and mount the GV unit directly to the back of the ZF, eleminating the GV carrier bearing mounting which is "less than perfect" he says. According to him, the GV unit would then mount directly with the adaptor instead of a transer case.
Anyone ever done this kind of swap? I would have to tear down the trans and rebuild it with the 4X4 rear case housing so more time and money. Would like to hear from someone who has actually done one.
Well, if you're going to do that, the ZF will need to be completely rebuilt...as towcat has demonstrated in past posts, when the ZF is put together, the rear housing is the first thing that goes on...so, if you want to replace it, the tranny has to be completely disassembled. It might be better to sell the 2WD ZF and buy a 4x4 tranny.
I'm wondering if your Doug Nash unit can be modified to work on a 4x4?
BTW, the last three pictures...the first two are an illustration of the differences in the floor pan inserts. In the second picture, the T-19 floor pan insert is sitting on top of the ZF, with about 3/4" left to go before the lip makes contact with the main floor pan. The last picture is of the pilot bearing that was in my T-19...and you can see what condition it's in. And, that's why I recommended the Kevlar bushing instead.