Modifying a worn out DMF

[MUDKICKR]

the only problem i see with welding it in the trk is that the flywheel will not be straight. if anyone has had a dmf flywheel in frt of them they know it bounces a little bit. if you weld it in the trk without bolting it down then you could weld it off center and have one hell of a viberation. i did this "lucky mod" without knowing that is what it is called. i just ran out of money and had a bad dmf flywheel. well i have had the non spring clutch disc in it and it works, but id rather have a spring clutch disc, if only i knew a part number for it id put one in.

 

[Mat J]

franklin pm rldsl i think hes the one with the 30wt atf i believe its synthetic i dont know how cold it gets, i think he also sells it, but big truck shops should carry it.

i think the reason alot of people dont weld it in the truck is because they wont have any springs in the clutch disk.

 

[65sixbanger]

Oh, in that case I'm down for it . I know the clutch was already replaced when I got the truck, but when I replaced it this time, I noticed the old disc had springs. It an LUK.

 

[65sixbanger]

Oh, in that case I'm down for it . I know the clutch was already replaced when I got the truck, but when I replaced it this time, I noticed the old disc had springs. It an LUK disc.

What do you mean by "It bounces"? Mine had no play other than circular?

 

[franklin2]

.....well i have had the non spring clutch disc in it and it works, but id rather have a spring clutch disc, if only i knew a part number for it id put one in.

Autozone carries it. Just look up your truck(mine is a 89) and look under clutches. Down at the bottom they list a disc only 10 1/2" and it's the one with the springs in it.

 

[Alex S]

Go for it, your going to have to replace it anyways if you dont. weld er up and let us know

 

[65sixbanger]

Ok I will probably do it either this weekend, or the one after that. Heck I could it at school tomorrow....

 

[RLDSL]

The only thing I think I would try next is a synthetic oil. They say it's not as thick when it's cold.

The thicker oil and overfilling it is to reduce the noise from the SMF(I have the Lucky Mod SMF). It does a fine job when it's all warmed up, still a little bit of noise, but tolerable. But it's a real struggle to shift when the oil is cold. The 30w oil is all but impossible to shift, and it was around 25f the other day. The truck would probably not even be functional if it got really cold with the 30w oil in it.

I don't know where to get 30wt tranny fluid, and if it's 30wt, it will probably still be too thick in cold weather. I am not sure of the official wt rating of the dexron that the zf calls for, but it looks pretty thin.

One other option I thought of was overfilling with dexron. I wonder how much that would reduce the tranny noise at idle?

What I'm running is 30 wt synthetic ATF and it shitfs in freezing weather way better when cold than the original atf( which is a 20 wt) did but it was not synthetic. The synthetic gives you the best of both worlds it's heavier, but it doesn't thicken up when it gets cold, it stays fluid, so you aren't grinding gears the first few blocks in the morning anymore.

 

[65sixbanger]

Ok I am going to do it either tomorrow or thursday, Anybody have any last minute suggestions? Or disagreements? I just wanna know whats best, However, the clattering is getting worse and tiresome

 

[65sixbanger]

Ok, well I just dont have the time or the want, to pull the tranny to do the lucky mod, otherwise I would. Any body else ever done this? Or have you ever heard of anyone doing this?
Anything will be considered..
Thanks,
-Lance

 

[TWeatherford]

If it were me, I would probably wait a few weeks until I could pull it out and do the lucky mod. However, if you feel that its going to fly apart tomorrow at 70 mph and split your bellhousing, you don't have much to lose by welding. If it does have a bad vibration after you weld it (because its unbalanced, not because its now a SMF), you'll want to park it until you can get another flywheel, whether it be new or someone's old DMF which you can then bolt together. My father had a subtle vibration after a clutch swap (97 PSD with ZF), and it destroyed the front bearing on the transmission in short order. You'll probably be fine welding if you do it carefully (but you better be better at welding than I am).

 

[65sixbanger]

I understand what you mean about the vibration, as it could lead to engine problems if it was bad enough, but I am going to be as smooth and consistent as usual. It should be fine, and if I notice more build up in some spots I can always grind on it.

 

[franklin2]

Someone who knows more about welding may be able to comment, but one problem I know with welding would be the stress build-up in the part. I don't know what would be the best method for welding it. Would you weld on it about 1 inch and then run it around 180 degrees and weld another 1 inch bead? And keep going back and forth till you filled it all in?

 

[Fordsandguns]

Someone who knows more about welding may be able to comment, but one problem I know with welding would be the stress build-up in the part. I don't know what would be the best method for welding it. Would you weld on it about 1 inch and then run it around 180 degrees and weld another 1 inch bead? And keep going back and forth till you filled it all in?

That is pretty much what my bil did on their service truck.

 

[sassyrel]

ANDDDDDD, when welding it--use real short beads--so create near no heat---you can weld grader wear blades--with 7018 DRY rod. with no cracking--but very short beads are required--------