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-   -   Is there a way to tell DMF or SMF without removing trans? (http://www.ford-trucks.com/forums/1326908-is-there-a-way-to-tell-dmf-or-smf-without-removing-trans.html)

MackGuy 07-23-2014 11:52 PM

Is there a way to tell DMF or SMF without removing trans?
 
I'm in the process of buying a 1996 PSD 5-speed, and I've heard a lot about this dual mass flywheel. Current owner has not had the truck long and doesn't seem to know much about it. Is there a way to check if the flywheel was changed other than removing the trans and clutch?

Can the flywheel be changed without removing the engine?

Does the clutch have to be replaced with the flywheel (the last owner put a new clutch in it)

Thanks!

Chris56ford 07-24-2014 02:13 AM

You can remove the 3 bolts on the flywheel cover and you can see the flywheel and clutch. If it is the dual mass it will be thicker. The ring gear and clutch surface of the flywheel will move separate of each other a little.

The dual mass flywheel has a spring system to absord shock. The springs are in between the clutch face and the ring gear portion.

Don't have to remove the engine to do the flywheel.

If going to a single mass flywheel, yes the clutch would need to be changed. The clutch on the SMF is bigger than the stock one.

MackGuy 07-24-2014 09:46 AM

Thanks so much for the good info. Is there a way to tell by inspection if a DMF is "going bad" or do the tend to be fine until they explode?

A shame you have to do clutch and flywheel together, since the truck has a relatively new clutch, the ~$300 for the flywheel wouldn't be too bad, but $1k for clutch+flywheel is quite a hit. Maybe I'll be lucky and it's already got a SMF in it.

DIYMechanic 07-24-2014 09:59 AM

The sound is the best way to tell is a DMF is on nits way out. Generally when they're starting to get loose they will exhibit a distinctive "clack, clack, clack" sound when you shut off the engine. What it is, is that the back half (Flywheel portion) of the DMF is getting sloppy and bouncing back and forth against the dampener springs when the engine stops abruptly. If you're hearing that, then now would be a good time to get it taken care of before it comes apart and wrecks the trans.

If the truck is more or less stock, you don't need to spend that much on a SMF conversion. A very nice LUK setup (which I highly recommend for a stock truck) will only run you about $275 on Rockauto. And it includes a new SMF, the disk, the throwout bearing, pilot bearing, pressure plate, and all the hardware. A great deal on a good clutch and as long as you're at or near stock power levels it will work really well.

More Information for LUK 07226

farmert 07-24-2014 10:03 AM

If you can rotate the DM flywheel back and forth more than 5/8 of an inch rather easily, it is on it's way out. Also it will have a vibrating rattle on shut down of the engine. It has a bearing in the center of the flywheel that can go bad, and it will give you a terrible vibrating shake from the tranny while driving. If that is the case, the tranny isn't long for this world, as it will crack the bell housing on the tranny. The conversion kit should be had for less than 1k for the kit. IIRC they run around 675 depending on the kit.

MackGuy 07-24-2014 10:41 AM

Quote:

Originally Posted by DIYMechanic (Post 14530468)
The sound is the best way to tell is a DMF is on nits way out. Generally when they're starting to get loose they will exhibit a distinctive "clack, clack, clack" sound when you shut off the engine. What it is, is that the back half (Flywheel portion) of the DMF is getting sloppy and bouncing back and forth against the dampener springs when the engine stops abruptly. If you're hearing that, then now would be a good time to get it taken care of before it comes apart and wrecks the trans.

If the truck is more or less stock, you don't need to spend that much on a SMF conversion. A very nice LUK setup (which I highly recommend for a stock truck) will only run you about $275 on Rockauto. And it includes a new SMF, the disk, the throwout bearing, pilot bearing, pressure plate, and all the hardware. A great deal on a good clutch and as long as you're at or near stock power levels it will work really well.

More Information for LUK 07226

Quote:

Originally Posted by farmert (Post 14530478)
If you can rotate the DM flywheel back and forth more than 5/8 of an inch rather easily, it is on it's way out. Also it will have a vibrating rattle on shut down of the engine. It has a bearing in the center of the flywheel that can go bad, and it will give you a terrible vibrating shake from the tranny while driving. If that is the case, the tranny isn't long for this world, as it will crack the bell housing on the tranny. The conversion kit should be had for less than 1k for the kit. IIRC they run around 675 depending on the kit.

Thanks for the link on that LUK... seems like a good way to go. Truck I'm looking at has an aftermarket exhaust but I don't think any crazy mods, and for the time being my trailer is probably <5klb so it wouldn't get worked too hard anyway.

Did not notice any unusual clatter at shutdown, and no vibration up to at least 45mph, so hopefully it's either SMF or not an immediate problem, but I will try to inspect once I can get it in my shop.

helifixer 07-24-2014 01:24 PM

LUK clutches can handle big loads. they might not be the best for sled pulling or drag racing but if driven nice they can handle the load. I am over 100,000 on mine and it tows all the time. my signature pic to over 30,000 lbs. I am leaving tomorrow night to get that same load and than another next week. over 400 miles and a lot of 6 to 7% grades.


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