My nephew has a 1988 F250 2wd 7.3/ZF5 project truck. The truck only has 95000km/60000miles on it. It's his first truck and we got it for a great price. The issue is that we thought the clutch was shot because it would barely move under it's own power. My buddy who is a heavy diesel mechanic pulled the tranny and found the DMF was shot. The center hub was spinning freely. He said the clutch is in great shape and there are no signs of heat scoring or heavy use. The truck looks in everyway that it was owned by a guy who took care of it but I wonder why the DMF let go with such low mileage.
My nephew is on a tight budget being 16. My buddy has a nice used DMF he will install for free with the original clutch that just has some surface rust he could clean off. Another option he said was I could just get a new SMF and use it with the original DMF clutch from the truck. Is this true and if it is what SMF is recommended? He also has a SMF clutch but no flywheel but he said the DMF clutch from the truck is in better shape. What do you guys recommend? My nephew will not be pulling large loads. Just cords of firewood, dirt bike, boat, etc. but I don't want him to kill the ZF5 by reinstalling a used DMF that may grenade because ZF5's are impossible to find locally. We don't even have a "pick-a-part" here anymore.
Thanks.

 

The odometer reads to 99999.9 then returns to ZERO!

 

Not the Canadian trucks. They have an extra digit on the odometer. It's 123456.7km(CAD) not 12345.6miles(US) So right now it reads 095000.7km It would have to have been 1,095,000km if it rolled over. This truck is clearly low mileage. Engine is spotless, great interior, etc.
We live in northern Canada, if this truck was +1,000,000km it would have rusted to nothing 10 years ago. The body is in great shape, better than trucks 10-15 years newer.

 

The DMFs are prone to failing and often taking out the bellhousing. This is why most upgrade to a SMF setup, and then add 1 extra quart of oil to the transmission to quiet down the gear rollover noise that happens at times(which the DMF would quiet).
This works quite well long-term; ask many of our members who have done this.

 

Thanks Macrobb. You've helped me before. Can the DMF clutch from the truck be used with a SMF and what SMF is recommended? My buddy is a diesel mechanic and said the DMF clutch can be used with a SMF. Or does he have to use a complete SMF kit? My buddy says he has a decent used SMF clutch we can have for free.

 

If I remember correctly, you take the shifter plate off the top of the tranny and fill it up to get the extra fluid in correct?

 

Yup; just 4 hex screws, under the rubber boot. Don't even need to remove the gear shift lever from the plate; the whole thing comes out as one.

 

No, DMF clutches tend to not have any springs on the clutch plate, the DMF contains all the springs.. Normal clutch plates have springs in the middle to help absorb some of the shock of the clutch engaging (at least I believe thats what they are there for).
Now, the DMF clutch that I originally had in my '88 did have some springs on the clutch, but it was like half what the SMF clutch had. There may also be size difference, I can't remember exactly.

I would recommend the Luk SMF conversion. It has a nice pedal feel and has worked great. The '93 had a Southbend SMF conversion done by a PO, it sucks! Feels just the like DMF, a rock hard pedal thats hard to comfortably use and is easy to stall.

If he wants to save some money for the moment, install the used DMF and start saving up for the Luk kit, its only like $350 or so if you search around.

Also, its rather easy to screw up the 'clutch' built into the DMF. Supposedly its there to protect the transmission from excessive torque from the engine. However, if the DMF gets hot, like from slipping the clutch moving around a trailer, or something like that, that safety clutch pack will slip, and from what I've heard once it slips the first time, it will keep getting worse. I had that happen on my '88. So driver error, or heavy use could cause it to slip and go downhill from there.

 

The other cheap solution (since you have an SMF clutch but no flywheel) is the "Lucky mod". Bolting the two halves of the dead DMF together to make it solid and run it with the SMF clutch. Not the best solution but many on a budget have done it...

 

Thanks everyone for the advice. With my buddy having a decent used SMF clutch(and I'm pretty sure he has the pressure plate as well), can we just get the LUK SMF? Or do we have to get the complete kit? If the LUK kit is $350US, thats $450CAD with the crappy exchange rate. That's alot of cash for my nephew who just got a part time job pumping gas.

When I looked on Rockauto, I found the LUK "RepSet" kit #07131 "Solid Flywheel Option; Aftermarket Turbocharger" which is the clutch and pressure plate for $205.32CAD.
More Information for LUK 07131
The LUK Flywheel is $121.27CAD. Part #LFW127. Solid Flywheel Option; Aftermarket Turbocharger. Is this the right one? He has no turbo on the truck
More Information for LUK LFW127

So it would be about $326CAD if these are the right parts to do everything or $121CAD just for the flywheel.

If these aren't the right parts, can someone give me a part number and the cheapest place to get the flywheel or kit.
Thanks.

 

Yes, the Luk LFW127 is the correct single mass conversion flywheel. Factory turbo trucks had heavier connecting rods and a differently balanced flywheel, that is why it specifies aftermarket turbo option. These are naturally aspirated trucks with a turbo kit added and they require the naturally aspirated flywheel. If the SMF friction disc and pressure plate look okay go ahead and use them, but do yourself a favor and get a new throw out bearing They cannot be lubed and you don't want to install an old one that's been sitting.

 

Thanks Ford F834. I'm going to call my buddy tonight to confirm he has the pressure plate and the diameter. I'll order the LUK flywheel and a throw out bearing. I couldn't find a listing for just the throw out bearing on Rockauto. Does it go by another name? Which TOB do you recommend?

 

And do I need to get different bolts??

 

The bolts should be the same, but be aware that the bolt holes in the crank shaft flange go all the way through to the crank case. Clean the bolts well and degrease them. Use thread sealer when you re-install them or oil can leak on to the clutch.

The throw out bearing is also called the clutch release bearing. I like Timken bearings, RockAuto has it... TIMKEN 614062 it's about $30 UDS but they make good stuff. When this bearing fails it can really wreck your day.... and it's not easy to change so to me it's worth the extra cost over the economy bearings.

 

I agree. I'd rather pay more and have it done right. You guys have been a big help. It's much appreciated. We may just put a new clutch and pressure plate to be safe as well. Are those the correct ones I listed above to go with the flywheel?