Was out in my 91 7.3 350 DRW with a ZF5 today doing errands, truck was doing great no noises, no vibrations or anything like that but when I was pulling out onto the road on my way back out of town my ZF5 started slipping like an auto does with a bad TC. Was no noises before or after it started, didn't slip the clutch just took off normally onto the main road using 1/2 to 3/4 go pedal to get up to speed and after 1/2 or so throttle the engine would rev without gaining speed almost exactly like when the TC was bad in the E4OD autos I've owned in the past. I stopped and looked under the truck tried to see if I could see smoke or smell a burning clutch but didn't notice either.

Aside from whatever is wrong the clutch seems to work fine, I can still take off like nothing is wrong and untill I get about 1500RPM+ where the powerband is goin strong or over half throttle-ish it drives like nothing is wrong. The trans goes into every gear 1-5 & reverse just fine and smooth as can be no grinds, no whining, nothing just does it exactly as it should. Hell it even drives fine long as you don't get heavy with the go pedal, when it starts to "slip" if you let off a bit it drives as normal.

Sounds like a clutch issue to me but I don't know for sure, any input would be greatly appreciated.

 

classic symptom of a dual mass flywheel failure. there is a small clutch disc in the flywheel that is doing that to you when the flywheel gets hot.
your best bet is to replace the clutch with a solid flywheel unit like the LUK clutch setup.
you can buy a solid flywheel, clutch disc, pressure plate, throwout bearing, slave cylinder and master cylinder for 1/2 of the cost of a dual mass flywheel alone.

 

Damn thats what I was afraid of, I found a few "kits" but I have no idea what you need to do it completely. Would http://www.ebay.com/itm/LUK-07-225-Clutch-Set-/170866632641?pt=Motors_Car_Truck_Parts_Accessories &fits=Year%3A1991|Model%3AF-350|Make%3AFord&hash=item27c871e7c1&vxp=mtr this have everything I would need to change it from the stock setup it is now and get my truck drivable agian? Thanks man I appreciate the help. In way over my head here.

 

That looks to be nice and complete, and not too terrible of price either

 

that is about all you need.

 

Thanks very much for the replies, put in the order for 1 of those kits.

 

Just wanted to post a quick AAR, finally got around to getting it installed. Apparently my DMF was worse off than I originally thought, with the new SMF kit installed there is less vibration in the driveline than before and no more shake on engine shutdown.

Still at low miles, but very pleased with the clutch so far. Extremely grabby, not a problem just have to get used to it, never had a clutch bite that hard and early in the pedal. Do have some rollover when lugging in gear, but none at idle in neutral. Not an issue at all IMO just added incase anyone was curious.

Would definitely recommend to anyone that was considering going to this setup from a DMF.

 

Sorry, I don't understand what you mean.

 

rollover is a term used to describe the noise you get when using a solid clutch setup in a ZF trans

 

I just converted to smf (12") from an 11" dmf, my clutch pedal effort got noticeably lighter. Did you experience the same?

 

Thanks, TJC.

 

My clutch pedal is extremely easy to push in now, about put a boot sized hole in the floor the first time I drove the truck with the SMF kit installed after being used to how it was previously.

 

I'm sure it was the flywheel, but I'll say this. When my ZF was in the truck, Whenever I would pop the clutch, It would slip and keep slipping until I let of the go pedal. I could floor the pedal when I started easy on the clutch and it wouldn't slip. I had a SMF. When I took the tranny off, I found what I think is the reason it slipped. The clutch/pressure plate, and flywheel where covered in a slick, slimy film of grease. Reason was the rear oil pan cover that goes from the back of the oil pan and around the shaft was leaking oil pretty good. It was a mess. Glad you got her fixed. My LUk clutch is very nice. Very responsive and even easier to push the clutch pedal. Shucks, If I would have spoken sooner, I could have let you have my ZF flywheel.

 

No worries dieselnut, I bought that kit the night I made the first post, pretty small window there lol, there was only 2 left and I wasn't going to miss out on that price. Appreciate the heads up on what was wrong with yours, I checked the oil pan gasket and the seals while everything was apart and easy to get to just incase and aside from a visit from Murphy its GTG. The clutch I took out looks to have alot of life left on it, I'd bet it had been replaced somewhat recently, but the DMF with its $$$$ pricetag was wasn't and thats why I had this problem. Either way I prefer the way it is now compared to how it was so while it sucks to spend the money, I'm happier and better off for it in the long run.

While I always buy used vehicles and that factors in, I hate the way OEM clutches feel even in my other vehicles, get about 1/2 - 3/4 of the way up and they slowly engage and don't bite solid fast, its a pain in the *** when hauling a load and stopping/starting or trying to manuver a trailer around with all the slipping you have to do. Never seen a 10k+ miles after review, so I don't know if the Luk's stay similar to the way they are new or not after you get thousands of miles on it, but it bites hard and fast currently just the way it should IMO and I'm going to enjoy the hell out of it for as long as it stays that way. Without a doubt with the way it engages it was alot easier moving all the stuff around the homestead the storms we've had here lately in WV have torn down, felt like I was actually driving a truck not a really big passenger car with a bed and some POS clutch.

 

Good. I like mine. With mine, I chirped the tires in second gear on dry pavement. That there says something.