6.9 zf5 swap
- Thread starter Jaker12367
- Start date
Every time I get on here I see someone wanting to use a 4 speed flywheel for the 5 speed zf. You can't do it, it won't work. Think about it. Why would they make special conversion smf flywheels for the zf if you could just bolt a 4 speed smf instead? Because the 4 speed flywheel won't work.
It would work, it would just self destruct. Search long enough one could find a disk with the correct splines, probably not cost effective though. Problem is the dampening springs are smaller and arranged in a smaller diameter to fit the t-19 flywheel. The smf conversion flywheels allow for the use of a larger dampening mechanism, allowing the aluminum case zf to survive behind a diesel. The other reason is t-19 were behind 6.9 and the flywheels are not correct for a 7.3, close but not correct. If your an aftermarket manufacturer and need to make a flywheel might as well make it for the application then copying a design thats would be full of comprimises.
Old Goat
Full Access Member
So true.
Think a year ago last Oct I replaced the Clutch assy with a Luc.
I had a spare FW, so took it down and had it resurfaced, so I had every thing for the R&R.
Get the old Clutch assy/FW removed from the truck , and notice
there is a difference when I set the new Disk/PP on the FW. I went to the 12" one, and checking the difference with the 11" or what ever was in it.
Then The light came on. The FW I had resurfaced was for a ZF-5
spd. and I have T-19 Trans. I forgot several years ago I bought
a 6.9 from a Forum Member that blew a head gasket, was going to fix that problem, but found a 7.3. Then put in an auto trans so his Wife could drive it.
I got the 6.9, FW and all the Turbo related stuff for $250.
So I did the wrong FW and then had to get the FW for the T-19
resurfaced. Think they charged $65 for ea one.
Not too many shops around anymore that resurface FW`s, as
now 99% of all new vehicles are auto trans.
Our society is becoming more shiftless all the time.
Goat
Will not work. I have never tried it, but I seem to remember the thickness of the two flywheels are different.
Nothing to do with the diameter. I did the Lucky Mod years ago and it is still running. That was taking the original DMF, taking it apart, and then drilling and bolting it together solid. At that time years ago Autozone sold a disc for the zf that happened to have springs in it. So that is what I used. Been over 15 years now.
Sammy
Registered User
Does work. I have done it with 6.9 flywheel. Clutch and pp came from the local rebuilder who’s been doing clutches for over 40 years now. Only part I don’t remember is what t/o bearing I used.
I would not recommend this route. Looks like a dmf pressure plate and clutch bolted to the 6.9 flywheel A smf conversion disk has a lot more springs.
http://www.randomthoughts.fyi/2012/07/adding-overdrive-bw-t-19-to-zf-5.ht
if any one could find archives on this link and it the one I am thinking of it would be enlightening. Hate when good info disappears on the internet.
http://www.randomthoughts.fyi/2012/07/adding-overdrive-bw-t-19-to-zf-5.ht
if any one could find archives on this link and it the one I am thinking of it would be enlightening. Hate when good info disappears on the internet.
If you used a different throwout bearing to compensate for the different depth, then yes it might work.
Lots of travel on a throw out bearing, may be enough to compensate. Also could just use a different disk with the t19 pressure plate.
Linctex
Registered User
1) The flywheel setback depth is different (about 1/4”?) , so the throwout bearing travel would be changed. You could modify a ZF5 clutch fork to make it work, but WHY bother.
2) The spring hub on the ZF5 clutch disk is larger, so the springs on the clutch disk would hit the 6.9 flywheel - because the relief is smaller. You could have a custom clutch disc manufactured, but what would that cost?
3) The pressure plate bolt patterns are different.
4) The ZF5 has a larger input shaft, so you would have to machine the 6.9 Flywheel center hole larger to take the larger pilot bearing
5) Quit messing around already.
All of the hassle is NOT worth it.
Just get the LuK 07-225 kit and be done with it.
2) The spring hub on the ZF5 clutch disk is larger, so the springs on the clutch disk would hit the 6.9 flywheel - because the relief is smaller. You could have a custom clutch disc manufactured, but what would that cost?
3) The pressure plate bolt patterns are different.
4) The ZF5 has a larger input shaft, so you would have to machine the 6.9 Flywheel center hole larger to take the larger pilot bearing
5) Quit messing around already.
All of the hassle is NOT worth it.
Just get the LuK 07-225 kit and be done with it.
IDIBRONCO
IDIBRONCO
No. Both flywheels take the same pilot bearing. The difference is in the splines that go through the clutch disc. At least as far as clutch swaps go.
Linctex
Registered User
OK - - - thanks for the correction
